Month: April 2024

Maier et al. also reported similar retention of total anthocyanins in gels stored for 24 weeks at 6 ◦C and 24 ◦C. The lower amount of anthocyanins recovered in the gummies stored at 4.4 ◦C compared to the same product stored at 21 ◦C may be explained by reduced extraction efficiency due to the hardening of the gel at low temperature, as opposed to degradation late during storage. Changes in the major individual anthocyanins in the gummy product stored at 4.4 ◦C and 21 ◦C over eight weeks of storage are shown in Figure S5. At 4.4 ◦C, all the individual anthocyanins decreased with storage time with retentions <50%, except for the two co-eluting anthocyanins galactoside + cyanidin-3- galactoside and malvidin-3-glucoside . The percent retentions of the rest of the anthocyanins at this storage temperature ranged from 29.3% to 49.2%. When stored at 21 ◦C, two anthocyanins did not significantly decrease with time, namely the unknown delphinidin derivative and the two co-eluting compounds galactoside + cyanidin-3- galactoside. For the rest of the anthocyanins, percent retentions ranged from 40% to 71% glucoside. In all the products, the individual anthocyanin loss did not appear to be impacted by the anthocyanidin structure or the type of sugar moiety attached .The distribution of the products according to their individual anthocyanin profile as affected by storage time can be visualized on a PCA scores plot . The first principal component explained 83.9% of the variation with all the individual anthocyanins being positively loaded on PC1. Therefore, PC1 represents the amount of individual anthocyanins.

The juice and ice pop samples had high scores on PC1 . The oatmeal bar samples also had positive scores on PC1 for the earlier storage times,blueberry plant pot whereas the oatmeal bar samples stored at 21 ◦C for eight weeks were the only oatmeal sample to havea negative score. Except for the control samples , all the graham cracker cookie samples had negative scores on PC1, regardless of the storage temperature. Finally, all gummy samples had negative scores on PC1, with scores becoming smaller with storage time. The PCA figure confirmed higher values of anthocyanins in the juice and ice pop samples, as well as, to a lesser extent, the oatmeal bars. The graham cracker cookie and gummy samples did not demonstrate high values for anthocyanins, with a clear loss of anthocyanins with storage time for the gummy samples.Percent polymeric color values typically show an inverse correlation with total anthocyanins during storage of blueberry products , and inverse correlations with each individual anthocyanins in all the products and storage temperature . Higher percent polymeric color values indicate that a higher percentage of anthocyanins are resistant to bleaching in the presence of potassium metabisulfite. Since the sulfonic acid adduct attaches at C4 on the middle heterocyclic ring, it is thought that anthocyanin–procyanidin polymers are formed via a direct condensation reaction, resulting in a C4–C8 anthocyanin–procyanidin linkage as the major polymers formed in blueberries during storage. Hence, it is possible that declines in anthocyanins during storage of the blueberry products are not true losses due to degradation, but the conversion of monomeric anthocyanins to anthocyanin–procyanidin polymers. Anthocyanins can be degraded via a hydration reaction, where the flavylium ion is converted to a hemiketal structure, which is rapidly converted to cis-chalcone, which slowly arranges to a trans-chalcone structure.

The trans-chalcone structure is highly unstable and rapidly degrades to hydroxybenzoic acid derivatives. However, we do not consider that this reaction was responsible for anthocyanin losses in the blueberry products over storage since we did not observe an increase in phenolic acid derivatives in our HPLC chromatograms at 280 nm . The stability of chlorogenic acid in the four blueberry products stored at 4.4 ◦C and 21 ◦C is shown in Figure 5. Chlorogenic acid was stable in all products over storage regardless of storage temperature,except for the juice and oatmeal bar stored at 4.4 ◦C, where levels significantly decreased . At 4.4 ◦C, the chlorogenic acid content decreased from 4.3 to 3.6 mg/g WBB powder in the juice and from 3.0 to 2.6 mg/g WBB powder in the oatmeal bar. At 21 ◦C, chlorogenic acid in the juice showed a slight increasing trend; however, this change was not statistically significant . Chlorogenic acid was also stable in the ice pop over eight weeks of storage at −20 ◦C , with an average value of 6.5 mg/g WBB powder over storage . Initial levels of chlorogenic acid were higher in all products stored at 21 ◦C compared with 4.4 ◦C storage, which may be due to the variation in processing the two sets of samples for the storage study, or possible the degradation of chlorogenic acid in the WBB powder used to prepare the products. The WBB powder used to prepare samples for the refrigerated storage study was stored at 15.5 ◦C for three months prior to preparing the samples. Blueberries contain polyphenol oxidase, which can readily oxidize chlorogenic acid. Chlorogenic acid was previously found to be stable in blueberry juice, puree, and canned berries stored for six months at 25 ◦C, but blueberry jams lost 27% of chlorogenic acid over six months of storage at 25 ◦C. Leaf footed bugs in the genus Leptoglossus Guérin-Méneville are large phytophagous insects native to the Western Hemisphere. At least 61 species are known, and several species are pests in forests or agricultural systems.

Many Leptoglossus spp. are multivoltine, which allows them to exploit multiple hosts per year. Direct damage to crops is caused when Leptoglossus spp. feed by probing their stylets into fruits and seeds, and secondary damage can occur through the transmission of pathogens at the feeding site. Field studies assessing the feeding damage of insects can provide information about the phenology of the pest and pinpoint when during the growing season insect feeding occurs, as well as determine when the crop is susceptible to damage or losses. Two species of Leptoglossus, Leptoglossus clypealis Heidemann and Leptoglossus zonatusare occasional pests feeding on almond and pistachio crops in the Central Valley of California. L. clypealis was considered to have a more limited distribution in the western United States, but is now reported to occur through the Midwest into Illinois,plastic gardening pots with some additional records from the east coast. While L. clypealis is noted in California for infesting almonds and pistachios, it has been recorded from at least twenty host plants throughout its range. L. zonatus is found in much of the Western Hemisphere ranging from Brazil into the southern United States on a wider range of host plants including citrus, pomegranates, almonds, and corn, among others. In California, Leptoglossus spp. are reported to overwinter in adult aggregations. As temperatures warm up in the spring, the adults disperse from aggregations and can be observed in almond orchards. Feeding by L. zonatus and L. clypealis on almonds results in clear sap exuding from developing fruit, known as gummosis. Early season feeding by these two species in March and April can result in almond drop, while feeding later in the growing season can directly damage almond kernels and result in losses. Both L. zonatus and L. clypealis are reported to be more abundant in the last few years, perhaps due to increased plantings of almonds in California. Approximately 1.36 million acres of almonds were cultivated in California in 2017, with an estimated value of $5.6 billion. Determining the level of damage from feeding L. clypealis and L. zonatus during the growing season in a field experiment will help determine the relative damage from each of these insects, and demonstrate when the almond crop is most vulnerable to Leptoglossus feeding, which in turn will help to determine the timing of prevention and control measures.

The objectives of this work were to determine the level of almond drop from feeding by adult L. clypealis and by L. zonatus, compare how almond drop varies during the growing season, consider almond size and its relationship to feeding damage, and quantify the final damage to almonds at harvest time from feeding by L. clypealis and L. zonatus. The effect of adult L. clypealis and L. zonatus feeding was evaluated on four almond varieties during the growing season from the end of March untilmid-August. The four experimental treatments included controls, mechanical damage to the developing almonds, feeding by adult L. clypealis and feeding by adult L. zonatus. All four treatments included an almond branch with approximately 20 almonds, covered by a sleeve cage consisting of a 5-gallon organdy mesh paint strainer closed with a large binder clip. Control branches with almonds served to determine the natural level of almond abscission during the growing season. The second treatment consisted of branches with almonds which were mechanically punctured to mimic feeding damage caused by the insect stylet probing into developing nuts. Each developing almond was punctured 4–5 times with a #1 insect pin . Puncturing almonds served an additional purpose, which was to provide an estimate of the time of shell hardening; shells typically became resistant to puncture by the end of April. The third treatment consisted of 5 adult L. clypealiswhich were allowed to feed for 4–6 d and were then removed. The fourth treatment was similar to the third but used 5 adult L. zonatus . For these treatments, insects were taken from the lab colony, and were first isolated with only water for 24 h before placing them into an experimental sleeve-cage. Each week in each almond variety, four branches were setup as controls, four were setup with punctured almonds, one branch each was setup with L. clypealis, and one with L. zonatus. For approximately eight weeks, the four treatments were replicated in the same manner on new trees in each of the four almond varieties. For Monterey and Carmel varieties in 2014, fields could not be entered on two weeks due to flood irrigation, and this resulted in six weeks of observations rather than 8. In 2015, the same experiment was repeated on the same four varieties, with the exception that feeding damage was assessed for L. zonatus but not for L. clypealis, due to an insufficient numbers of adult L. clypealis to complete the experimental replicates. Each week, data were recorded on the number of almonds fallen from branches within all cages that were setup in previous weeks. These data were used to determine the mean percent almond drop in each of the four treatments for each of the four varieties. An analysis of variance test was considered to compare means, but data were not normally distributed, even after log transformation. Thus, nonparametric Kruskal–Wallis tests were used as they do not assume a distribution for the data. Post-hoc pairwise comparisons were by Steel–Dwaas tests and were considered significant if p < 0.05. In 2015, similar comparisons were made for the mean almond drop for three treatments within each almond variety. To examine when almonds were most susceptible to almond drop from feeding by each Leptoglossus species, the mean percent almond drop was compared among the experimental weeks within each bug feeding treatment. A Chi-square goodness of fit test was used to first examine whether the percent almond drop from a Leptoglossus species was equal among the weeks of the study for each almond variety. If almond maturity had no impact on insect feeding damage, the percent drop would be equal among weeks of the study. When a significant difference among weeks was observed, subsequent tests were by Fisher’s Exact tests to compare pairs of weeks . Just before harvest, the almonds remaining in field cages were removed to conduct a final damage assessment. For each control and each branch with mechanically damaged almonds, a sub-sample of four almonds was used to assess several damage parameters. For branches caged with L. clypealis or L. zonatus, all remaining almonds were removed and used for the final damage assessment. Four parameters of feeding damage were determined, hull strikes, almond kernel necrosis, strikes on the kernel, and shriveled kernels. A strike on the hull was characterized by a black or brown spot. A strike on the kernel was the third type of damage. The fourth and final damage type was whether or not the almond kernel was shriveled. Damage was recorded for each category as presence or absence.

Decreased extraction despite crop intensification was largely enabled by increases in irrigation efficiency, including decreased water losses during transport to fields and basin-wide implementation of drip irrigation . Drip irrigation is known to produce much less off-field sediment transport during the irrigation season than sprinkler and furrow irrigation techniques. Thus, large scale conversion from furrow to drip irrigation led to decreases in irrigation water use, and may have also played a role in decreasing Salinas River suspended sediment concentrations in the latter 20th to early 21st centuries.Decreasing trends in suspended sediment concentration-discharge relationships were observed in the lower Salinas River from 1967-2011 despite increasing activities of wildfire and agriculture in the watershed over this period. Increases in effective burn area and total crop area have been generally found to increase sediment production at the watershed scale. Shifts in crop structure were dominated by a rise in row crops over this time period, which would also have been expected to increase sediment production. Row crop fields of are often left bare over the winter, rendering them prone to rainfall/runoff driven erosion, and degradation of the necessary drainage networks of earthen ditches can result in further increases in sediment export . With the exception of changes in irrigation practices, potential control of decreasing suspended sediment loads from other anthropogenic activities can be discounted due to limitedareal extent or timing. Urbanization increased,blackberries in containers but only to approximately 2% of the Salinas River watershed area.

While urbanization can lead to decreases in discharge-corrected CSS values by increasing the production of runoff from precipitation without concomitant increases in sediment production , no shift in the P–Q relationship was observed in the Salinas River between 1967 and 2011 . Conversely, the damming of Salinas River subbasins and attendant sediment trapping has been estimated to have significantly decreased sediment flux relative to pre-dammed conditions . However, dam emplacement in the Salinas Watershed occurred before the period of suspended sediment record, and the trapping characteristics of their reservoirs are not expected to have changed significantly over the intervening years . Wildfire activity was insufficient to counteract the negative inter-decadal trend in suspended sediment load, even though the years with the highest effective burn areas in the Salinas River watershed fell toward the end of the record. There was some indication that the large fires preceding the 1978 water year, coupled with the high Q-producing storm events of that year, may have increased suspended sediment load in agreement with the findings of Warrick et al. . However, other years with high effective burn areas and relatively high Q-intensities did not express consistent increases in CSS. The lack of wildfire control on inter-decadal scale trends in sediment loads may be due to issues of scale and the areal extent of burning. Often findings of dominant wildfire control come from studies of small, headwater catchments that have experienced burning over a high proportion of land area . Indeed, the suspended sediment flux from the Arroyo Seco subbasin was found by Warrick et al.to be highly controlled by the coincidence of wildfire and large storms on the basis of two instances of nearly complete burning of the watershed’s oak and chaparral shrublands.

The role of fire in maintaining chaparral vegetation communities and dominating sediment production in the semi-arid foothills and low mountains typical of coastal central and southern California has been extensively reported . In contrast, the undammed Salinas River watershed is an order of magnitude larger than the Arroyo Seco, with about half the average relief, and extensive agricultural development consisting of irrigation agriculture in lowlands and extensive grasslands on lower foothill slopes. As a result, even the largest EBA calculated for the Salinas River were only 10% of the undammed watershed . Thus the larger land area of the Salinas River watershed with numerous tributary drainages and divides and attendant mosaics of vegetation and microclimates has resulted in a mosaic of small wildfires relative to watershed size during any given fire season. Disconnected fire patches would be expected to produce less effective transfer of fire generated hillslope sediments to channels, in contrast to that of a completely burned watershed. Lowlands in the mainstem drainage network of the Salinas River also likely present a sink that moderates the signal of hillslope sediments produced from burned land surface, further obscuring the signature of more extensive burn years . Lavé and Burbank found a similar disappearance of wildfire control on inter-decadal scale sediment production when scaling up from small, 10-1 to 101 km2 scale headwater subbasins to 102 km2 scale watersheds in the San Gabriel Mountains of the southern California. Furthermore, semi-arid systems with intermittent flow and high discharge losses to groundwater recharge like the lower Salinas River tend to have longer residence times for suspended sediment due to increased incidence of in-channel deposition, particularly during flows into dry channels . Previous and continuing alterations to the Salinas River and its watershed may have exacerbated the attenuation of hillslope sediment production signals by destabilizing the channelized system of the lower Salinas and drawing down the ground water table.

Widespread deforestation along the banks of the lower Salinas River in the 19th century seemed to have decreased bank strength and led to a transition from a single meandering channel to a disorganized sandy active corridor, with localized and incipient braiding, which persists today. Intensive groundwater pumping remains above replacement , which could further exacerbates this scenario of lowland moderation of highland sediment production signatures by increasing the proportion of channelized flow abstracted to groundwater recharge . Indeed, early wet season flows have been observed to completely attenuate before reaching gauges S1 and S2, and thus completely depositing their suspended sediment loads into the channel . A more direct human cause of the overall negative trend in CSS, and the period of low CSSf that has persisted since the mid-1990s, is the conversion of agricultural operations to drip irrigation. Previously dominant methods of irrigation, particularly furrow, were known to produce large amounts sediment from off field transport and irrigation canal erosion . Drip irrigation has been shown to result in much lower off-field transport of sediment than sprinkler and furrow methods , and was introduced to California in the early 1960s. Large scale shifts in agricultural practices toward drip irrigation was contemporary with the decrease in suspended sediment concentration-discharge relationship observed for fine and sand sized sediment in the lower Salinas River. Although drip irrigation was used for only ~ 14% irrigated land coverage by 1993, over the next 17 years land area under drip irrigation quadrupled, replacing sprinkler and furrow methods as the primary irrigation practice in the Salinas Valley. This change in irrigation technology may be the dominant driver of not only the decreasing fine and sand sediment production trend found from 1967-2011, but also the timing of the departure from the hydrologic and climatic controls that Gray et al.found for fine sediment in the late 1990s to early 2000s. Drip irrigation has largely replaced older methods of irrigation for certain crops throughout California and other semi-arid or dry-summer climatic regions over recent decades, primarily due to increases in yields of high value row crops such as tomatoes . Widespread adoption of drip irrigation for such crops could have the unintended side-effect of reducing the entrainment of agricultural sediments into fluvial systems in these regions, which may have beneficial water quality consequences. Fluvial sediments are the greatest single impairment of rivers and streams in California,blackberry container many other parts of the U.S. and the world . Furthermore, agricultural sediments are often exposed to surface reactive nutrients such as phosphates, and multiple pesticides, many of which are hydrophobic and primarily transported off-site in association with fine sediments . Although winter season erosion remains an issue on such fields in single cropped areas, the time period between pesticide application and off-field is much longer for sediments eroded during the winter, perhaps decreasing winter off-field sediment associated pesticide fluxes. Thus, increases in drip irrigation use could yield a potential benefit in reducing the delivery of agricultural sediment to water bodies, particularly during the times when these sediments are most contaminated.It is well recognized that the inadequacy of conventional approaches for characterizing the key parameters and monitoring the key processes at over large enough areas yet with high enough resolution hinders our ability to optimally manage our natural water resources.

High resolution geophysical methods, such as GPR, hold promise for improved and minimally invasive characterization and monitoring of the subsurface. Here, we review several case studies where we have successfully used GPR for a variety of environmental and precision agricultural investigations. Section 2 focuses on the use of GPR for estimating parameters that are important for environmental and agricultural applications, such as hydraulic conductivity, sediment geochemistry, lithofacies zonation, and water content. Section 3 focuses on the use of time-lapse geophysical methods for assisting with remediation investigations, such as for to detecting biogeochemical hydrological processes that occur during remediation and the distribution of remediation amendments. This collection of case studies illustrates the utility of GPR for environmental and agricultural applications. Geophysical data are being increasingly used in hydrogeological site-characterization to obtain a better understanding of heterogeneity and its control on flow and transport. Such data can bridge the gap between the typically sparse conventional field characterization data and the need to realistically parameterize numerical transport models. In this section, we focus on the use of GPR to estimate hydrogeologic parameters that are important for agricultural and environmental studies, such as: water content, lithofacies zonation, hydraulic conductivity, and sediment geochemistry. Many of these studies also involved the development and use of stochastic estimation methodologies, which have enabled us to systematically fuse GPR and other sparse but direct measurements. Recent studies have shown that careful irrigation management can have beneficial effects on many crops, including almonds, citrus, prunes, pistachios and wine grapes. In particular, moderate water stress on grapevines early in the growing season can have a positive impact on grape quality. Thus, understanding when and how much irrigation to apply is critical for optimized wine grape production. Natural geologic processes, however, can cause soil variations and associated water-holding capacity to vary significantly, even over distances of a few meters. Given that the “industry standard” to vineyard soil characterization is to collect soil or water content measurements on a 75 m grid, grape growers typically do not have enough information about water content variations to guide precision irrigation. We have used GPR methods to estimate soil water content within agricultural sites in a non-invasive and manner and with high spatial resolution. Using 900 MHz GPR ground wave travel time data, we have estimated soil water content distribution in the top 15cm of the soil layers at high spatial resolutions and as a function of time at the Robert Mondavi Vineyard in California. Comparison with conventional ‘point’ soil moisture measurements, obtained using time domain reflectometry and gravimetric techniques revealed that the estimates of GPR-obtained volumetric water content estimates were accurate to within 1% by volume. The density of the obtained water content estimates was perhaps the highest density shallow moisture measurements obtained to date; the study produced 20,000 measurements of soil water content over the 3 acre study site. Water content distribution in deeper layers can also be obtained using GPR reflection arrivals if sufficient contrasts in dielectric properties exist. For example, Figure 1 illustrates the average volumetric water content estimated using data from 100 MHz GPR reflections associated with a subsurface channel, located 1.0-1.5 m below ground surface at a 2 acre Dehlinger Vineyard Chardonnay block in Sonoma County. Figure 1 shows how the channel has influenced subsurface water distribution, and suggests a correlation between water distribution and canopy density . At this site as well as the Mondavi site, it was clear that water content distribution was linked to soil textural and canopy vigor variations. Huisman et al. provide more information about the use of GPR for water content estimation. We have used cross-hole geophysical data to provide multi-dimensional estimates of hydraulic conductivity at a DOE bacterial transport site located near Oyster, VA.

We use our estimates of the response of global crop productivity to temperature change as an input to the GTAP CGE model in order to determine how national economic welfare is affected by climate impacts on crop yields. Figure 5 gives the global damage functions within the impacted sectors. Among all the cases that include CO2 fertilization, welfare changes are negligible at 1–2 degrees of warming, becoming negative at 3 degrees. In contrast, the No-CO2 case shows substantial global welfare losses, even at 1–2 degrees. Uncertainty bounds are large meaning no cases are statistically different from the reference case at the 95% confidence level. But the uncertainty in potential yield losses is also highly asymmetric: the possibility of large welfare losses is substantial whereas welfare gains are both smaller and less likely, particularly for a warming of 2–3 degrees. These welfare changes depend on modeled changes in harvested crop areas, production intensity, and consumption. We believe there is a general perception that empirical studies give more pessimistic estimates of crop response to warming than do process-based models . However, there is a lack of systematic comparisons between the two methods. In particular, because empirical studies do not include CO2 fertilization whereas process-based studies generally do, it is important to account for this difference in comparing the temperature response from the two methods. Here we are able to do this statistically, showing that once CO2 are controlled for, differences between empirical and process-based responses may be smaller than generally believed. Though the point estimates do show some evidence of more negative impacts from statistical studies at higher temperatures ,growing blueberries in pots the effect is not precisely estimated and error bars are large.

The poor representation of empirical studies within the yield impacts database, particularly at higher levels of warming, is a major limitation of this analysis. Inclusion of more recent studies would help with this, but this is not always straightforward. Many recent papers report the marginal effect of growing degree days rather than average growing season temperature and converting from one to the other is not simple . Standardized reporting of the impacts of a 1 °C increase in average temperature in empirical papers would help with this and should be encouraged. In addition, as noted above, the number of points at which the continuous response function estimated in empirical papers should be sampled for inclusion in the database is inevitably arbitrary. Some standardization would be useful and would help with interpretation in the future. Another finding from this paper is that there is little evidence in the existing literature that farm-level adaptations will substantially reduce the negative impacts of climate change on yields. The results presented here suggest that many actions described as adaptation in yield modeling studies would raise yields both in the current and in the future climate, meaning they do not necessarily reduce the negative impacts of future warming. If actions would confer benefit in the current climate but are not being adopted, economic logic suggests that models may be either overestimating benefits or they may be missing important costs of implementation. In either case, the potential for within-crop, farm-level adaptations that improve yields in the future climate more than in the present climate appears limited, at least as currently represented within the studies included in the meta analysis. This paper confirms the importance of CO2 fertilization in determining the average global impacts of changing temperature over the 21st century. Our results show the question of whether or not CO2 effects are included is more important than either the inclusion of adaptation or the type of study used to estimate the temperature response.

For both maize, wheat, and rice, CO2 fertilization fully offsets negative impacts of warming up to 1–2° for the global average yield effect. This demonstrates the importance of future work to better constrain the magnitude of this benefit. While we find good agreement between our results and those derived from FACE experiments, at least for the C3 crops , there is evidence that the fertilization effect depends critically on water and nutrient availability . Capturing this heterogeneity in CO2 fertilization by crop and farming intensity could be important in improving estimates of the yield impacts of climate change at both global and regional scales. Because of the importance of the CO2 fertilization effect, it should be clearly communicated when climate change impacts are presented without CO2 fertilization, which is often the case with statistical papers and sometimes with process-based models . Finally, this paper makes the connection between models of crop productivity and economic welfare. This is an essential step for informing damage functions in the simple Integrated Assessment Models such as DICE, PAGE, and FUND used to calculate the SCC . The economic impact results further underscore the importance of the CO2 fertilization effect: global welfare effects at 1–2 degrees of warming are negative without the CO2 fertilization effect but slightly positive for cases that include it. These results also show the complex connection between yield and welfare change. Despite error bounds on yield impacts being more or less symmetric, these same yield impacts give rise to highly asymmetric distributions over welfare changes, with substantial probability of large welfare losses. This asymmetry arises, despite the fact that the GTAP modeling framework allows for a large number of economic adaptations to moderate the adverse consequences of productivity shocks including changing inputs, shifting crop areas, trade adjustments, and consumption switching.The agricultural industry is often cited as a classic example of a competitive market. The observed performance of such markets, however, is the result not only of competitive forces but also of governmental intervention. Such intervention is often motivated by equity or distributional concerns.

Typically, the impact of such governmental intervention is evaluated only in terms of output markets . Such investigations are grossly inadequate since governmental policies impinge directly on asset as well as flow markets for both inputs and outputs. In general, the distributional consequences depend upon the ownership, utilization, quality, and technology associated with the assets. This paper develops a framework for capturing the distributional implications of governmental intervention in the agricultural sector recognizing its most important features. These features include competitiveness, asset fixity, rapid technological change, and institutional limits to credit availability. The first three features are documented by Theodore Schultz, Willard Cochrane, and G. L. Johnson. Theodore Schultz has also called attention to the large differences in the rates of return to resources among regions as well as across producers. Much of this variation emanates from differences in production techniques, human capital, and wealth controlled by individual producers. The limitations of credit availability for producers of different size classes have been noted by recent empirical evidence. This evidence strongly suggests that larger farmers borrow more; they borrow more to invest in capital; and their ability to borrow more stems, in part, from their higher repayment capacity . The equity and efficiency impacts of selected government policies have been addressed by a number of different frameworks, most of which are based on aggregative relationships. For example, in the agricultural development literature, aggregative relationships are specified for an agricultural sector and a non-agricultural sector. The micro-economic foundations of these frameworks, however, are not generally specified. As a result,drainage gutter the thorny problems of aggregation are pushed aside. Also, the distributional content of results forthcoming from such models is not very rich. The purpose of this paper is to advance a framework for evaluating the impact of governmental policies on agricultural production systems that is internally consistent at both the micro-level and the aggregate level. Assuming the major source of economic growth is technological change, the framework focuses on the incentives and constraints for technological adoption. Both the efficiency and distributional consequences of various policies are shown to depend upon landownership, land utilization, and the technology associated with land assets. To accomplish these purposes, a stylized model involving two technologies, traditional and new, is specified. At both the micro-level and the aggregate level, the framework admits a number of important features including uncertainty, varying degrees of risk aversion, both fixed and variable costs of technological adoption, and credit as well as land constraints. The model design allows the evaluation of a wide array of various policies. This set of policies includes price support, credit-funding enhancement, credit subsidies, crop insurance, price stabilization, input subsidies, and extension promotion. The basic micro-economic foundations of the framework are developed in section 2. Section 3 focuses on the micro-economic behavior of various farmers under alternative policies. Aggregation operators are applied in section 4 to capture the relevant macro-level causal relationships. Finally, the concluding section examines the operational use of the framework. The focus of this paper is on the qualitative efficiency and equity effects of various policies. In the context of a simple theoretical model which incorporates a number of important features of the economic environment, propositions have been derived which reveal ~ny insights for policy analysis. However, to operationalize these propositions, a considerable amount of empirical estimation is required.

Empirical analysis must begin by decomposing the farming population into relevant classes. This decomposition can be accomplished endogenously by the specification of a discrete/continuous behavioral model. The district choice relates to tedmology while the continuous choice is the amount of explanatory variables appearing in this model include the vector of expected returns defined by technology, the variances and covariances of returns defined across technologies, the variable cost of new inputs, the opportunity cost of financial funds, the fixed setup costs of various technologies, and available credit. Estimated relationships between the above explanatory variables and discrete technology choices and continuous land allocation choices are one component of the required empirical structure. estimation of the distribution of landholdings. A second component is an One potential distribution is the Pareto distribution specified in section 4. A third empirical component must relate the distribution of farm size to risk preferences. Estimation of this relationship will most likely require the use of primary data from representative samples. The final empirical component requires a set of linking equations between the policy instruments and the specified explanatory variables. For example, the empirical relationship between price supports and the vector of mean returns and the covariance matrix of returns across technologies must be determined. Armed with these four empirical components, a number of operational uses of the proposed framework are possible. First, one can simply simulate the effects of various policies through the four empirical components to determine the most effective integration of the various policies. This potential use of an empirical version of the proposed framework can only capture the quantitative effect of the proposed policy mixes; no attempt would be made to identify the optimal set of policies. Various trade-off relationships or alternative weightings in a scalar criterion function including two principal performance measures, efficiency and equity, could be specified. Theory and’ intuitive reasoning can be utilized heavily in isolating those trade-offs which allow a set of scalar criterion functions to be examined by parametric analysis. When such critierion functions cannot be captured, again, parametric analysis can be utilized with some objectives expressed as constraints motivated, perhaps, by a lexicographic ordering and/or as satisficing arguments. Various solution algorithms that can be employed to enhance the determination of a global optimum are available . Another potential use of the four empirical components relates to the notion of political economic markets. In a positive analysis of government behavior, the four components can represent a constraint structure which, along with a specified criterion function, can be used to infer, via revealed preference methodology, the trade-off between efficiency and equity . Such a positive analysis would allow economic researchers to perform effectively a role of social critics; that is, if past policies imply a value scheme which in some sense deviates from the public interest, then the implicit choice of trade-offs between efficiency and equity should at least be debated. Along similar lines, various economic interest groups could also employ the four empirical components to determine which set of policies they are prepared to support or oppose. Cooperatives are corporations that are owned and governed by the firms or people who use them; they differ from other businesses because they operate for the benefit of their members, rather than to earn profit for investors. Cooperatives have played an important historical role in promoting the economic welfare of California’s agricultural producers.

The data – the 1995 intercensal survey of Indonesia –the identification strategy, and the specifications follow closely Duflo . The reader should refer to that article for more details. We first replicate Duflo using a dummy for agricultural employment, rather than log wages as in the original paper, and show that the program-induced exogenous increase in schooling led the affected cohorts to work less in agriculture. We then use a different specification to show that the magnitude of the effect of schooling on agricultural employment is in line with the estimates of Section 5.1.Since Schuh’s famous paper, the effects on the agricultural sector of exchange rates and monetary policy have been a subject of much interest and controversy in agricultural economics. Increasing attention has been paid to the role played by shocks emanating from the monetary and financial sectors of the economy. The magnitude and duration of the effects of these shocks on the agricultural sector is still not resolved. For the U.S., some studies find monetary factors to be important. while others disagree.Part of the difficulty in reconciling the different conclusions available in the literature is that no common theoretical model underlies these studies. However, if monetary policies are to be considered important forces in determining agricultural market conditions, a theoretical framework must be developed in which this proposition can be evaluated. Otherwise, empirical analyses which purport to show significant real effects of exchange rates, intl.ation. etc.,lack the theoretical background against which results can be judged. In this paper, we discuss a model of price and exchange rate dynamics in which there are short-run effects of monetary policy. They take the form of relative price changes which benefit the agricultural sector during expansionary monetary policy regimes and which turn against the sector when money is tight.

These results are based on the exchange rate overshooting model of Dornbusch, in which short-run exchange rate changes in response to money growth can exceed. or overshoot,greenhouse ABS snap clamp their long-run equilibrium values. Unlike the Dornbusch model, in which all goods’ prices are fixed, agricultural prices in our model are assumed to be flexible. and we focus on the importance of this assumption for the agricultural sector. The model is consistent with rational expectations and asset market equilibrium at every point in time, and with the long-run neutrality of money. We adopt a “fix-price, flex-price” fr<lm~work, to use the terms originating with Hicks. Prices of agricultural commodities, because those goods are homogeneous. frequently traded, and storable. are assumed to be flexible and governed by instantaneous commodity arbitrage. Non-agricultural goods. on the other hand, are more often differentiated products, with contracting, less rapidly disseminated information, and imperfect competition as possible causes of less rapid price adjustment. Price adjustment therefore occurs instantaneously in the flex-price agricultural markets, while fix-price, non-agricultural ,I markets respond gradually to changes in aggregate demand. The paper has two main sections. The first half focuses on some of the theoretical background and some empirical evidence on the stickiness of prices. First, a review of the model of agricultural price and exchange rate overshooting is given. Next, we consider the factors affecting the degree of overshooting and present some empirical evidence for the United States. Results are presented for Australia which are also suggestive of different speeds of adjustment between agricultural and non-agricultural prices. The second half of the paper describes some simulation experiments using a structural model of the U.S. agricultural sector. In the interest of conserving space, only a brief overview of the model is given, but Figure 1 gives a representation of the model structure. The paper concludes with a discussion of the implications of the results for agricultural policy and suggestions for further research.The overshooting model was developed by Dornbusch to explain variability in flexible exchange rates. In his model, all goods prices were assumed to be sticky, adjusting less rapidly than the pric12s of assets . This causes short-run exchange rate changes in response to changes in the money supply which are greater than the long-run outcome. A simple example illustrates the application of the concept of overshooting to food prices in a pure exchange economy. Consider two goods markets, say, food and widgets, and assume that there is a currency but the quantity of real balances demanded is perfectly inelastic.

When a doubling of the money supply occurs in the presence of perfect price flexibility, doubling of the food and ” widget prices follows immediately and money is neutral. The doubling of the price level leaves the quantity of real money balances unchanged, and equilibrium quantities of food and widgets are also unaffected. The flexibility of prices is the key. Now, assume that food is a ft.ex-price good, while the price of widgets adjusts slowly over time in response to changes in aggregate demand. With short-run fixity in the price in the widget market, such an adjustment is prevented. If the food price alone doubles after a doubling of the money supply. there is excess demand for goods and excess supply of money balances. The continuing effort of money holders to rid themselves of excess money balances guarantees further food price increases. If the widget price gradually rises over time, initial relative prices can be restored. Thus, what would be observed in this simple world is an overshooting of the food price in response to money growth. with the food price falling gradually back to its long-run equilibrium, while the widget price gradually rises to its long-run level. The longer it takes for the latter change to occur, the longer the food price will be above its eventual level. As long as there are no impediments to the eventual doubling of the widget price. the end result is that of the price flexibility case, with relative prices urtchanged. An important factor is omitted from this simple example, the interest elasticity of money demand. It was assumed tpat under no circumstances would individuals hold real money balances in excess of the initial stock. If the quantity of money demanded responds positively to decreases in the interest rate, however. the above result is not necessary. It is easy to see that, the greater the willingness of individuals to hold extra real balances, the less the effect of money supply changes on the food price in the short run. That is. the more interest elastic is money demand, the less will be the degree of overshooting. However, the change in the interest rate brings capital markets into the .’ picture. Departing from this simple model of a closed, exchange economy, let us introduce a world capital market and currencies. Assume that the home country in question is a small country and assume that uncovered interest parity holds, so that home and rest-of-world nominal interest rates differ only by expected depreciation in the value of the home currency.

The domestic nominal interest rate can only change if there is an expected appreciation or depredation of the currency at the same time. Dornbusch used this setup to show that there would be exchange rate overshooting following a change in money growth, as long as the prices of sticky-price goods had not reached their new long-run equilibrium levels. He assumed that all goods were subject to this gradual price adjustment. Frankel and Hardouvelis observed that it is possible to substitute the prices of commodities for currency prices in Dornbusch’s model, and found that asset market equilibrium conditions applied to the market for storable commodities guarantee the same outcome: nominal commodity prices overshoot their eventual levels in response to changes in money growth rates.Stamoulis et. al. used the Frankel and Hardouvelis assumption that agricultural commodities are flexible-price-goods, but kept the exchange rate in the model, as well. The law of one price was assumed to hold at all times for the agricultural commodity, so that its price was never out of line with rest-of-world prices,snap clamps ABS pvc pipe clip while gradual price adjustment again characterized non-agricultural prices. The model thereby differs from the Dornbusch model only in allowing some goods to have flexible prices. The home country is assumed to be a small country in both agricultural commodity and capital markets. This and the law of one price assumption guarantees that the domestic nominal food price will follow exactly the same path as the value of the home currency, so that it overshoots its long-run equili- ” . brium and that this condition persists as long as adjustment in remaining, sticky-price goods markets lags behind. Comparison of the path of adjustment resulting for flexible prices with the Dornbusch solution reveals that, as the number of flexible-price goods in the economy rises, the degree of overshooting is reduced. Thus, the results provide an intermediate case between complete flexibility of prices and the case of stickiness of all goods’ prices. The appendix to this paper contains a short derivation and description of these results. These results depend on few assumptions. The price of agricultural commodities must be free to adjust, as can the exchange rate, while non-agricultural commodities must be characterized by slower adjustment. The model does not require a violation of rationality on anyone’s part, provided one adopts the view that there are good reasons for the existence of contracts, costly price adjustment, or other factors contributing to the stickiness of prices elsewhere in the economy. In fact, Dornbusch showed that overshooting is consistent with rational expectations at every point in time. Also. there is no reliance on the substitution of other countries’ agricul-tural products for the home country’s exports; the law of one price was assumed to hold. To the extent that it is violated. say. because of price supports limiting the downward flexibility of prices. weak export markets can be expected to add to these relative price changes in the case of tight money. In the fix-price. flex-price framework, the short-run effect of monetary policy thus shows up in relative price changes. An expansionary regime favors the agricultural sector in the short run, since relative prices favor agricultural producers, while tight money has the opposite effect, causing larger and quicker decreases in agricultural prices than in non-agricultural prices.Our version of the overshooting model depends on-the assumption that the economy can be described by two types of goods, flex-price goods such as agricultural corrunodities and financial assets, and fix-price. or sticky price goods, such as many non-agricultural commodities. Evidence concerning the relative stickiness of non-agricultural prices comes mostly from ad hoc regressions in which price indices or their growth rates are linked to money growth rates and possibly some other causal factors such as income growth. Based on quarterly data. the evidence is much stronger in favor of the relative stickiness of non-agricultural prices than it is for actual overshooting of agricultural prices. Money growth does appear to have a greater initial effect on agricultural prices, but the effect is probably not greater than one-far-one. We have not tested for overshooting of the exchange rate variable, but if the exchange rate does overshoot its long-run equilibrium. the same result need not apply to the price of agricultural commodities. This is the case if the law of one price does not hold instantaneously for agricultural commodities.Results given in Stamoulis et. al. for the United States were based on the method used by Barra to construct an anticipated money growth variable. Regression of the growth rate of the U.S. Department of Agriculture’s index of prices received by farmers on current anticpated money growth rates revealed an effect much larger than for the Consumer Price Index or for the nonfood CPI. The lagged dependent variable was found to have a larger and significant coefficient in the latter regressions, consistent with the gradual price adjustment assumption used above. Meanwhile, the coefficient on the lagged dependent variable was small and insignificant for the growth rate of the index of prices received by farmers. These results were consistent with those of Lombra and Mehra, who found that the cumulative effect of money growth is I greatest in the consumer price index for food, but that it has larger initial effects. the less is the processing component in the food price index examined. Depending on data and specifications used for estimation. results of tests of neutrality do appear to vary across studies.

The cationic surfactants created numerous positive charges on the adsorbent surface, which increased its retention of negatively charged VO4 3− in solution. Notably, some studies showed that surfactant modification decreased the BET surface area of adsorbents. For example, tetradecyl trimethyl ammonium bromide treated corn straw had a lower BET surface area than that of the original straw . This phenomenon might be caused by the blockage of pores and loss of access to internal surface area; however, the loss of surface area did not affect the enhanced adsorption performance of the modified agricultural waste for acid red, acid orange and VO4 3− due to a concomitant increase in the number of positive sites. Sodium dodecyl sulfate is a common anionic surfactant used to improve the adsorbent performance for positively charged pollutants. Pirbazari et al. determined that surfactant molecules created aggregates on the surface of rice straw, which promoted the formation of a porous adsorbent structure during the modification. SEM characterization showed that the surface of modified straw was rougher with a specific surface area of 150 m2 g− 1 compared with 58 m2 g− 1 for the original straw, which provided an enhanced adsorption capacity for methylene blue. In addition, a -SO3 group was attached to the surface of the modified straw further increasing the adsorption capacity. Similarly, studies have demonstrated that sodium dodecyl sulfate treated peanut husk exhibited a high removal efficiency for rhodamine B dye in solution . Kinetic studies demonstrated that the adsorption of rhodamine B by the modified peanut husk was best described with a pseudo-second-order kinetic model, indicating that chemical interactions played a dominant role in the retention of the rhodamine B dye. Surfactant-modified agricultural waste products for the removal of a diverse range of aquatic pollutants are summarized in Table 7.

The maximum adsorption capacity of sodium dodecyl sulfate treated peanut husks for rhodamine B was 240.0mg g−1 ,drainage pot which was about a 100-fold increase compared to the pristine husks . Pollutant adsorption onto the modified adsorbent was mainly controlled by a hydrophobic interaction mechanism, along with a considerable contribution from a cation exchange mechanism . In addition, cetyl trimethyl ammonium bromide strengthened π-π interactions for organic pollutants due to the increasing role of benzene rings in the adsorption process . As a result, the adsorption performance of modified wheat straw for Congo red dye was about a factor of two times higher than for the untreated straw. Although a decrease in BET surface area may occur in surfactant-modified adsorbents due to the constriction of pore channels by attachment of surfactant moieties, the overall adsorption performance for several pollutants increased due to an increased number of positively charged surface sites . Overall, surfactant modification is a feasible method for improving adsorption performance due to significant changes in surface properties of the adsorbent, such as the hydrophobicity, hydrophilicity and functional groups.Grafting of polymers onto the surface of agricultural wastes is an important technique for selectively imparting the chemical characteristics of the polymer to the waste structure. Therein, the backbone of a polymer is linked to a side chain of lignocellulose in agricultural waste to form a branched copolymer . Grafting-to, grafting-from and grafting-through are the three main linkage types, which are based on the type of polymer. The process involves the addition of monomer units to form copolymers on the adsorbent surface, which transforms the surface functionality . Usually, grafting-from treatment occurs in an aqueous environment and a suitable initiator is required to induce the modification reaction.

Chemical, radiation and photochemical processes are the main techniques employed to initiate the grafting process. For example, a chemical initiator generates free radicals to react with -OH groups on lignocellulose and is widely used due to its ease of operation and low cost. Potassium permanganate , potassium persulfate and ceric ammonium nitrate 2Ce6 are common initiators for polymerization of monomers on agricultural wastes . Many monomeric species, such as acrylic acid, acrylamide, acrylonitrile and aniline, are used for the synthesis of a polymeric adsorbent surface . These monomers usually contain acidic or basic functional groups. Corn stalk was modified with an acrylonitrile monomer in the presence of KMnO4 as the initiator , resulting in the -OH groups of cellulose reacting with the monomer to form copolymers on the surface. A FTIR spectrum indicated the presence of -CN functional groups and the N content of the corn stalk increased from 1.11% to 4.02%. The grafted material sorbed Cd2+ yielding an activation energy of 9.43kJ mol−1 , indicating that the Cd2+ retention mechanism was a chemical process. Further, the adsorption behaviors of Indosol orange RSN and Indosol black NF by polyethyleneimine-grafted peanut husks were studied by Sadaf et al. . Te -NH and -C=O functional groups were introduced by the modification process and the adsorbent surface became rougher as determined by FTIR and SEM analyses, respectively. As a result, the Indosol dyes reacted with the carboxylic and carbonyl functional groups leading to their efficient removal. Additionally, Fotsing et al. demonstrated that polyethyleneimine-grafted cocoa shell was an effective material for the removal of NO3 − and Cr6+ from solutions. The pHpzc value of modified cocoa shell was 9.3, much higher than untreated adsorbent due to the large number of amino groups grafted on the material surface. Amino groups on the surface of the modified adsorbent reacted with H+ during acidic treatment, producing a surfcial-NH3 + moiety, which subsequently adsorbed NO3 − and Cr6+ through electrostatic attraction. Polyaniline grafting to agricultural wastes strongly alters their physiochemical properties, which in turn strongly alters adsorption performance for various pollutants.

For instance, Soldatkina and Zavrichko prepared a new composite by chemical polymerization of aniline on the surface of corn stalks using ammonium persulfate 2S2O8 as an oxidation agent and H3PO4 as a dopant. H-bonding and π-π interactions between aniline and cellulose in the corn stalk structure anchored aniline frmly to the surface of the material. Moreover, the specific surface area of the adsorbent increased from 15.1 to 46.9 m2 g−1 after modification, facilitating physical adsorption of acid red and acid orange dyes. In addition, π-π interactions between aniline and the two dyes promoted chemical adsorption. Some reagents can also exhibit excellent adsorption performence for pollutants without changing adsorbents surface structure srongly due to the unique properties of reagents. For instance, β-cyclodextrin has a well-developed three-dimensional structure and numerous -OH, which made modified rice husk adsorb Pb and bisphenol A quite effectively . β-cyclodextrin grafting accomplished synergetic Pb and bisphenol A elimination through averting their competitive behaviors owing to diverse capture mechanisms for Pb and bisphenol A . Grafting treatment improves agricultural waste adsorption for several pollutants as summarized in Table 8. The adsorption capacity of Congo red dye by polyphenolic tannin treated jute fber was much higher than for the untreated fbers . The N atoms in -N=Nand -NH2 and S and O atoms in the -SO3 − moiety of the modified adsorbent participated in removal of Congo red dye via formation of intermolecular hydrogen bonds with the -OH moiety of the dye. Further, aniline modified corn stalk exhibited high adsorption capacity and efficiency for acid red and acid orange compared with unmodified corn stalk . Adsorption equilibrium occurred within 120–150min and the adsorption capacity of the modified corn stalk was ~2 times more than that of raw stalk . Grafting treatment of agricultural wastes has also been shown to enhance adsorption performance for inorganic pollutants. Acrylonitrile-modified corn stalk showed a maximum Cd2+ uptake of 12.7mg g−1 compared with 3.4mg g−1 for raw corn stalk, owing to an increase of -CN groups that promoted metal complexation . Similarly, polyethyleneimine-modified peanut shells increased the number of positive charges on the modified surface,drainage planter pot thereby strengthening electron attraction for Cr6+ in the pH range of 2.0–11.0 . Sorption of Cr6+ followed 2nd-order kinetics and a Freundlich-type isotherm, with a maximum adsorption capacity of 24.8mg g−1 . Overall, the primary adsorption mechanisms for grafted adsorbents were complex formation and electrostatic attraction between the grafted functional groups and pollutants in the solution.O-containing functional groups play a predominant role in surface reactions, hydrophobic/hydrophilic characteristics and electrical properties of adsorbents . Te -OH and -COOH moieties are among the most abundant functional groups and participate in a wide range of adsorption mechanisms with various types of pollutants . The adsorption of heavy metals and dyes by HNO3 modified agave bagasse and oreganum stalks increased due to generation of -OH and -COOH on the surface of the modified materials . The -OH and -COOH groups may dissociate to form of -O− and -COO− upon interaction with water .

These acid ionic functional groups can interact with cationic pollutants through ion exchange or electron attraction mechanisms. The -C=O and -C-O groups are commonly associated with modified agricultural waste products . For example, NaOH treatment increased the -C-O- content of wheat straw, which enhanced Cu2+ adsorption . Te Cu2+ adsorption occurred primarily through a complexation interaction between -C-O- and the metal . Given the multi-functionality of modified agricultural wastes, most complexation reactions involve interactions between the pollutant and multiple functional groups, such as -OH, −COOH, −C=O and -C-O. For instance, NaOH-modified orange tree sawdust resulted in generation of -OH-, −COO- and -C-O groups, thereby promoting the retention of methylene blue through complexation reactions with each of the different functional groups . Similarly, − C=O, −C-O and -COOH groups in corn straw bio-char interacted with triazine via electrostatic interactions resulting in effective removal of triazine from solutions . In summary, modification of agricultural wastes to generate additional O-containing functional groups increases pollutant adsorption, primarilythrough complexation reactions, hydrogen bonding, Van der Waals interactions and electrostatic interactions.N-containing functional groups are introduced to the surface of the agricultural material through etherification modification resulting in generation of -NH2, −NH and -C-N . Te N atom has a lone pair of electrons that serves as an activation site to trigger interactions with pollutants. Qu et al. showed that N doping introduced graphitic/pyridinic N on adsorbents for serving as reactive sites during the reaction, Pyridine N could transfer electrons from phenol to persulfate, while graphite N trigger nucleophilic addition of persulfate to generate 1 O2 to degradate phenol further. In general, the N-containing functional groups on modified agricultural wastes increase the basic properties of adsorbents, thereby generating negatively charged surfaces to enhance the sorption of cationic pollutants . For example, NaOH treatment exposed more -NH groups on the adsorbent surface, which strengthened the material’s affinity for Hg2+ and Cu2+ through complexation and electrostatic attraction . Similarly, modification with triethylamine increased -NH2 concentration on modified adsorbents resulting in enhanced Ni2+ retention via electron sharing with the N atom . N-containing functional groups can also form positive charges to attract anionic pollutants following protonation of the -C-N group in acidic environments to form -C-N+. For instance, a modified coconut shell fber with increased -C-N group content exhibited strong attraction for nitrate, sulfate and phosphate with maximum adsorption capacities of 33.7, 31.2 and 200.6mg g−1 , respectively . Similarly, −NH2 can be converted to -NH3 +upon acidifcation, which effectively retained Cr6+ through electrostatic attraction . Thus, N-containing functional groups provide modified adsorbents with the capacity to retain both cationic and anionic pollutants depending on the pH of the reaction environment. Additionally, N-containing functional groups often interact synergistically with O-containing functional groups for retention of pollutants, such as toluene, methylene blue and acid red 18 .S-containing functional groups on modified agricultural wastes can enhance the sorption capacity for several pollutants . Sulfur is loaded onto waste materials through a sulfuration treatment, such as solution infltration or gas activation . The sulfuration process introduces -S=O and -S-O moieties to the modified surface to enhance pollutant adsorption. For example, H2SO4-treated coconut shell generated numerous -S=O and -S-O functional groups that substantially increased the adsorption of methylene blue through electrostatic attractions, H-bonding interaction, and π-π interaction . Further chlorosulfonic acid activation of matured tea leaf bio-char generated additional -S=O and -S-O functional groups, which participated in retention of Rhodamine B and orange G through complexation and electrostatic interactions . Grafting of -C-S, −C=S and -S-S to adsorbent surfaces has also been used to improve adsorption properties. For example, sugarcane bagasse reacted with ethylenediamine and CS2 produced a material with exceptionally high adsorption capacities for heavy metals , with -C-S functional groups participating in the metal complexation reaction .

Arslan et al. echo this conclusion, finding that opportunities for wage employment contribute to the empowerment of young women and the rural economic transformation by speeding up the demographic transition. The dynamics described above raise the prospect of farm labor shortages over time, especially shortages of wage workers needed to meet the growing demand for food and agricultural products. This situation is already observed in high income countries across the world. Global press coverage documents labor shortages and reliance on immigrant farm workers on every continent where crops are commercially grown . The COVID-19 pandemic has served as a stark reminder of high income countries’ reliance on immigrant agricultural labor. There are four options to deal with farm labor shortages, which Martin characterizes as the 4 S’s: Satisfy, Stretch, Substitute, and Supplement. Farmers can satisfy and retain existing workers by offering them higher wages, less onerous working conditions, benefits, and bonuses to make work on the farm more competitive. Farm employers can stretch the workforce by increasing worker productivity, providing workers with better technology like slow-moving conveyor belts to carry harvested produce that enable workers to pick faster. The option to substitute may entail replacing laborers altogether by labor-saving technologies or relying on food imports instead of local production. And finally, farmers can supplement the existing workforce with foreign guest workers. All four strategies are being deployed to different degrees, depending on countries’ preferences and their position in the evolving labor surplus-shortage continuum. The corresponding public policy domains are labor and social protection,pot with drainage holes innovation and competition, agricultural trade, and migration. These go well beyond the traditional realm of the Ministry of Agriculture.

This broad global assessment of the future of AFS work zooms in on the roles of productivity-enhancing innovation and technology and immigrant agricultural labor. The choice is motivated by persistent low labor productivity in African agriculture, the salient digital revolution, and rising anti-immigration sentiment in current policy debates. solutions . Others view research and development as largely an exogenous, self-perpetuating process: new inventions lead to others by lowering the cost of technological development over time . Both could be at work in practice, with the development of digital technologies, for example, partly driven by forces exogenous to agriculture, but their adaptation and adoption in agriculture partly driven by the rising costs of labor. A famous example of labor-saving technology in fruit and vegetable production was the processing tomato harvester developed by researchers at the University of California, Davis and commercially released by Black welder in the mid-1960s . Within five years of its commercial release, virtually 100 percent of processing tomato farms in the United States used the harvester, and most planted a tomato variety genetically engineered to go with it. Integrating mechanical engineering and agronomics was a novel feature of the tomato harvester’s genesis. Over the next 35 years, harvest labor requirements per ton of processing tomatoes dropped by 92%, while the U.S. processing tomato harvest more than doubled .Recently, R&D has combined mechanical engineering with information and technology to find labor-saving solutions for more difficult to-mechanize crops and activities . Automated harvest of fresh fruits, like peaches and strawberries, is particularly challenging, requiring “smart” technological solutions like mobile robots, mechatronic systems with precision sensing, actuation capabilities, and robots that can handle soft, flexible, and complex objects.

These machines and other sensors also gather data, which, in combination with cloud connectivity, advanced analytics, and machine learning algorithms, create a world of new possibilities to manage and increase efficiency along agri-food chains. The result can include a reduction in the use of other inputs, as well as labor, reducing the adverse impacts of food production on the environment as well as on farm workers’ health, for example, by reducing chemicals in the food chain. Many of these high-tech solutions are still in the development and experimentation stages, but others are “on the shelf” and already in common use . Clearly, if ever it was accurate to think of agriculture as an intrinsically low productivity sector, that time has passed. California’s tomato harvesters and “robots in the fields” seem far away from farms in low-income countries. Nonetheless, increasing agricultural labor productivity in the developing world will require increased use of technologies that enable the agricultural labor force to become more efficient and remain inter-sectorally competitive . As a result, agricultural productivity gains in much of the world may need to be induced primarily by more basic technologies, like small tractors, or mechanical devices that automate repetitive labor intensive tasks, such as mechanical rice transplanters. In some places, expansion of agricultural machinery services offers the possibility of increased mechanization on farms too small to justify the outlay to purchase machinery themselves. For example, Yang et al. report that in China, “in response to a rising wage rate, the most power-intensive stages of agricultural production, such as land preparation and harvesting, have been increasingly outsourced to special service providers.” In China, the use of these services has promoted a more efficient division of labor, allowing urban migrants to maintain higher-wage employment off the farm during the planting and harvest seasons . The increasing use of machinery services is not confined to Asia. It is also observed in Africa and increasingly facilitated by digital platforms, such as Hello Tractor in Nigeria,an app-based Uber connecting smallholder farmers to affordable tractor service providers.

Nonetheless, many organizational hurdles to developing the integrated machinery chain needed to make it profitable remain . Socioeconomic constraints can also stand in the way. Gulati et al. , for example, report low adoption of mechanical rice transplanters in India due to women’s weak bargaining position in the household decision making process. Mechanization is often associated with a reduced demand for labor. In theory, the impact of mechanization on labor demand and wages is unpredictable. This is because of two opposing effects: substitution and scale. Agricultural mechanization often occurs in response to rising rural wages, following the structural transformation of national economies towards industry and services, which draws labor out of the agricultural sector. As rural-urban migration expands, greater urban income earning opportunities become the main driver of agricultural wages. Higher wages induce farmers to mechanize and substitute capital for labor, as has now also been observed in Vietnam . Mechanization can also enable farmers to expand the scale of their production and increase their income. This can even happen without an original increase in wages, especially in land abundant countries. In fact, it can even induce an increase in real agricultural wages and hired labor , though the use of some intermediate labor-saving inputs like herbicides can mitigate this . An observed concurrence of rising agricultural wages with mechanization would suggest that wages induce farmers to adopt labor-saving methods, but when scale effects outweigh substitution effects, mechanization does not necessarily reduce rural employment. It is not surprising, therefore, that the evidence on the labor effects of mechanization is mixed. Kirui reports that in African countries where land expansion previously was limited, mechanization has led to scale effects through an increase in the amount of cropland cultivated . Scale effects have been accompanied by input intensification, higher productivity in maize and rice production, and greater labor use. However, in a number of countries, he also finds that mechanization displaces labor and induces off-farm work in some cases. Overall, where there are limits to agricultural extensification, for example, due to labor scarcity and rising wages, increasing labor productivity through technological change, including mechanization,large pot with drainage is the key to expanding food supplies.As technology changes, better educated and trained workers will have to be available to complement new advanced technologies.

Digitized agriculture and food systems also require a digitally-skilled workforce. In most cases, technologies and skill demands in poor countries are not as advanced as in high-income countries like the United States, Western Europe, or Japan. Nonetheless, studies from developing countries reinforce the need to train workers for more skill-intensive employment, not only on farms but throughout the food supply chain, as the agricultural transformation unfolds and digital agriculture takes hold . The COVID-19 crisis may present an opportunity to accelerate the digitization of the agri-food system, helping players across the globe in all nodes of the AFS become more efficient and informed while bridging the ruralurban divide by improving participation in modern markets . Solar energy and mini-grids also offer important opportunities to increase labor productivity in agri-food, especially now that the cost of productive use leveraging solar energy products, such as solar driven water pumps , cold storage, and agri-processing equipment, is falling, appliance efficiency is increasing, and new business models are emerging.The two main policy areas for promoting mini grid expansion and greater adoption of PULSE products are becoming financially sound, through charging cost recovery tariffs and/or targeted government subsidies and having regulations that specify what happens when the large grid reaches the mini-grid areas. On both fronts, many initiatives are ongoing . The adoption of these technologies could accelerate agricultural labor productivity growth, especially in Africa and South Asia; enable the development of delocalized agri-processing through refrigeration; and facilitate a more productive release of farm labor. In countries further along in the development process, the transition out of agricultural work is often accompanied by an inflow of immigrant workers, who help grease the wheels of farm labor markets by replacing native-born workers no longer willing to do farm work . Reliance upon immigrants has been a quintessential feature of the history of farm labor in the United States, particularly in the state of California, where two thirds of the nation’s fruits and nuts and one third of vegetables are grown. It is also widespread in other high-income economies, as well as many not-so-high-income ones like Costa Rica , Dominican Republic , and South Africa . In recent decades, California farmers have relied overwhelmingly on unauthorized migrant workers from Mexico. However, rural Mexicans are also transitioning out of farm work as families become smaller, children become better educated, and non-farm employment expands . Workers have become less willing to travel far away from their homes to work on farms for extended periods of time . Yet, when farm workers are less mobile, even more are needed to meet seasonal labor demands.The declining supply of immigrant farm workers and their reduced mobility has induced local labor shortages. In some cases, this has prevented farmers from being able to harvest high-value fruit and vegetable crops, which have simply rotted away in the fields . Expansion of the U.S. H-2A agricultural guest worker program is unlikely to offer a long-term solution, as labor recruiters compete with Mexican farmers for a diminishing number of farm workers. Mexico is expanding its fruit and vegetable production, in part, by importing farm workers from Guatemala, while sending fewer farm workers to the United States. Increased immigration enforcement has further led to an exit of immigrants from local farm labor markets and pushed unauthorized Mexican migrants further into the desert to avoid apprehension, leading to an increase in the number of border-crossing deaths . These factors have exacerbated an already deteriorating situation for U.S. farmers and have led to a humanitarian crisis on the U.S.-Mexico border. These trends are not specific to California or Mexico. They have been observed across high-income countries and are evident in other middle-income countries. Agricultural guest worker programs are common on all continents, in countries with vastly different incomes, and they tend to be controversial everywhere. The extent to which middle- and high-income countries already rely on immigrant labor has been highlighted by the COVID-19 pandemic, which caused governments across the world to enact emergency measures to relax mobility restrictions for agricultural workers to safeguard food production. Examples include the U.S. , Canada, Germany, and Spain , and Portugal and Italy . Migration can benefit migrant-receiving areas, beyond the farmers themselves, to the extent that migrants complement native workers, make agricultural operations more competitive, and stimulate the demand for goods and services. More importantly, from a development perspective, migration can benefit those who remain in the migrants ending economy . Migrant farm workers often earn much more than they could in their place of origin, and the income they remit to family members can help loosen constraints on household production activities, generate income spillovers for other households, and create other positive externalities.

Both studies detail establishment and first year production and harvest costs for not-yet-fully-mature crops. For raspberries, first year of production includes a $12,460 per acre construction, management and investment cost for protective tunnels. Costs for a mature raspberry crop are analyzed in the second production year and total $48,210 per acre . For blackberries, costs for a mature crop are shown for the second through fifth production years, and total $43,406 per acre per year. Harvest costs again represent the vast majority of total costs, at 81% and 71% of total costs for raspberries and blackberries, respectively. For raspberries, cultural costs represented a much smaller share of total costs at $4,656 per acre, roughly half of which was for trellis and tunnel management. Blackberry cultural costs totaled $5,709 per acre, of which over half was for pruning and training canes. Each study also includes an analysis of potential net returns to growers above operating, cash and total costs for a range of yields and prices. When evaluating net returns above total costs, gains are shown for higher yield and price points; losses are also documented at many lower yields and prices . Farms with productive soils, experienced managers, optimal production conditions and robust market plans generally realize higher net returns. In contrast, farms with less-than-optimal production conditions, reduced yields, poor fruit quality or inexperienced managers may contribute to lower net returns. Results from the strawberry analyses show that on a per acre basis,vertical vegetable tower organic strawberries tend to be more profitable than conventional berries, even with lower yields.

Organic price premiums explain the result; in this example price per tray for organic strawberries ranged from $12 to $18, while price per tray for conventional berries ranged from $7.30 to $11.30. Prices for second year conventional strawberries were slightly lower still to account for a portion of the crop that was diverted to the freezer market. Net returns for both caneberries were mostly positive. Other noteworthy entries in all recent berry studies include per acre costs for pest control advisers , management of invasive pests and food safety and regulatory programs for water and air quality. Though each alone represents a relatively small portion of total costs, they provide readers with insights into the changing nature of berry production activities and costs over time.Cultural practices in the berry industry have evolved to address changes in soil, water and pest management needs. New varieties have been developed to enhance yield and quality attributes. Based on historical trends, and to meet both industry needs and consumer demands, we expect to see new varieties continually developed over time. Businesses have responded to consumer and market demands for fresh, safe and organic products by implementing food safety programs and/or transitioning more lands to organic production. Water and air quality programs have been developed to comply with state regulatory requirements. In the past, growers customarily hired those with expertise in financial and market management; they now also enlist the support of experts in food safety, organic agriculture and environmental quality to assist with farm management. But challenges remain, and management of key agricultural risks — including those for production, finances, marketing, legal and human resources — have become increasingly important.

Invasive pests pose significant management and regulatory constraints and increase production, financial and market risks. Two recent examples are light brown apple moth and spotted wing drosophila . LBAM infestations can lead to loss of part or all of the crop because of field closure from regulatory actions, increasing production and financial risk. SWD presents substantial market risk to growers in that its larvae can infest fruit and render the crop unsaleable. Growers minimize the risk of loss from these two organisms with the routine use of PCAs. PCAs monitor fields more frequently than growers alone would be able to do, identify pests and recommend actions, for example, the use of pheromone mating disruption for LBAM and field sanitation for SWD.Since their introduction, the soil fumigants CP and MB have unquestionably contributed to the expansion of the berry industry. However, the full phaseout of MB as a pest management tool — it will no longer be available for use in berry production after 2016 — presents both production and financial risks. While a substantial research commitment has been made to finding alternatives to MB, nothing has yet come close to offering the same level of protection from the large-scale loss to soil pathogens or the gains in productivity associated with the application of CP and MB as synergistic preplant fumigants. We anticipate that the berry industry will adapt to the MB phaseout by using alternative fumigants and preplant soil treatments, but these are likely to carry a higher level of risk for berry production in the short term and may lead to a decrease in planted acreage and production. However, this may also stimulate an even more robust research agenda directed towards soilborne diseases and plant health to minimize disruption to the industry. Reliance on fumigants as the primary strategy for pest management is almost certainly a thing of the past. Instead, adoption of integrated approaches, including alternatives to fumigants, to manage diseases, weeds and other pests will be key to sustaining berry production over the longer term .

Social and demographic changes in Mexico — the source of a majority of the area’s agricultural labor — have resulted in markedly lower immigration rates into the United States, a shrinking labor pool and upward competition and wage pressures for the agricultural workers who remain . In recent years, growers have reported difficulty in securing and retaining sufficient numbers of workers to ensure timely and effective farm operations. The lower production figures seen in strawberries in 2014 may in part have been the result of an insufficient labor pool from which to draw . However, no known regional employment or wage data are available to specifically document this. Some growers minimize labor risk by paying higher wages and providing year-round employment when possible. However, these strategies can be difficult for some businesses to justify economically. Arguably, the area’s berry industry, and agriculture more generally, increasingly face political risk. Immigration legislation that may assist with the current labor challenge languishes at the federal level, with major policy changes unlikely before 2017 . Farming practices are under ever more scrutiny by consumers, local municipalities and state and federal agencies. Soil fumigants and pesticide use have been the focus of many intense debates and discussions, especially in Santa Cruz and Monterey counties. At the time of this writing, several new regulations related to pesticide application notifications, pesticide and fumigant application buffer zones and worker safety have been proposed by the California Department of Pesticide Regulation or the U.S. Environmental Protection Agency but have not yet been finalized. It is anticipated that implementation will begin in 2017, with full compliance required in 2018. And, as California struggles through a fifth year of drought, water use, quality and cost has become a more robust part of the local, state and federal discourse, with directives issued and new legislation proposed. Compliance with each new directive or regulation presents production and logistical challenges for growers and can be costly to manage. Although it is unlikely that regulatory pressures will lessen in the future, there is every expectation that growers will continue to adjust business practices to meet or exceed any new requirements or standards. The economic sustainability of individual farming operations and the area’s berry industry in total will ultimately be impacted by and continue to evolve with the ever changing business environment,vertical farm tower and by an array of risks and challenges.While there is evidence that drought causes individuals to reduce water consumption, household demand remains somewhat inelastic . In periods of drought, the majority of water reallocation falls to industrial consumers and in particular the agricultural industry which consumes 80% of non-environmental allocated water in California . While this may spark scarcity innovation through investing in new technology or selling and trading water permits, there are substantial costs from unexpected changes to a water supply. In this paper, I investigate whether drought can create local spillovers into sectors closely related to the agricultural industry, using the distinct variation in drought intensity to compare compositionally similar counties.

Empirical evidence suggests that price volatility in times of crisis creates considerable spillover in closely related industries . I attempt to test this hypothesis with the 2012 to 2016 California drought, a hydrologically significant event that primarily impacted the Central Valley. I use cross-sectional data to analyze outcomes utilizing a difference in difference methodology to compare the counties in the Central Valley that experienced a greater intensity of drought with those that narrowly evaded costly impacts. Drought creates reductions in water supply that cause farmers to employ large-scale shifts to groundwater usage, less water per crop and increased reliance on water-conserving technology . Over pumping groundwater has the potential to create unquantifiable long-run impacts on the environment and permanently reduce the natural ability to replenish available aquifer levels.1 In future drought occurrences, lower levels of groundwater will increase pumping costs, particularly in Central Valley counties that relied heavily on groundwater from 2012 to 2016 . Although groundwater pumping is common, farmers that require more water than what is available from either state allocated water contracts or pumping face several choices. They can sell state allotted water permits to industrial consumers to recover a portion of losses, switch to drought-tolerant crops, or fallow portions of farmland.Fallowing is often the last choice, as farmers forgo all profit generated from owning and operating the property and are likely to reduce the hours their employees work. Fallowing creates sizeable direct costs to the industry in productivity and job loss .California agriculture is the national leader in terms of food sales, making up 11% of total exports in 2012. The lucrative industry was valued at $37.5 billion in 2012 and has been growing rapidly. Despite the drought, agricultural exports had a valuation of $46 billion in 2016 . Estimates suggest output would have been much higher if the drought had not occurred. Total direct statewide economic losses to agriculture from the drought were $3.8 billion solely from 2012 to 2016 . We know the 2012 to 2014 drought in Southern and Central California was the most severe occurrence in the last 1200 years by paleoclimate reconstructions of past droughts . The impact of the drought in terms of crop losses and job layoffs manifested primarily in the Central Valley, an inland area consisting of 18 counties. An estimated 72% of the crop losses in the height of the drought were contained in the San Joaquin valley and Tulare River basin . Although agriculture statewide did not sustain extreme losses, job losses and pumping costs were distributed unequally. After using groundwater pumping to recover the majority of the water shortage, the remaining 10% shortage in statewide agricultural water use was accommodated by fallowing half a million acres of farmland. Approximately 90% of that fallowed land was in the San Joaquin Valley and the Tulare river basin. Other compositionally similar areas such as the central coast depend on different water sources that were not similarly impacted by the drought . The 2012 to 2016 California drought highlighted the inadequacy of rural well and water systems, particularly in certain rural communities that lacked running water at the height of the drought. Tulare county suffered one of the greatest losses in crop production as well as bearing one of the highest costs of groundwater pumping. Due to reduced groundwater levels in Tulare, there were approximately 2,000 domestic well failures solely in 2015 . These small and often low-income areas are not always required to have contingency plans or links to larger water supply systems. Related literature has shown that rural and low-income individuals have less tolerance for natural disasters. A similar drought occurred in Australia from 2001 to 2004 and was estimated to be equivalent to an annual reduction of $18,000 in income. However, this impact appeared only for individuals living in rural areas . This result emphasizes differences in responses between demographic groups to natural disasters. Current literature aims to understand this differential to effectively implement welfare programs such as the relatively new Drought Housing Relocation Assistance Program implemented in 2015 .

It is worth mentioning that at all the three tiers of sites, cross-scale sensing technology should be able to provide already rich remote-sensing based observations, which should provide the necessary model inputs and model constraints for MDF. Tier 1 – Super sites: This tier includes sites that have collected a complete suite of measurements data that can be regarded as gold standard datasets . An ideal super site should include measurements that range from biogeophysics to biogeochemistry , i.e. a dataset that is sufficient to recreate the soil-plant-atmosphere continuum, and evaluate/benchmark the major ecosystem processes simulated by models. Thus a typical super site should at least include eddy-covariance flux tower, extensive and deep soil samples, ground-level remote sensing, and various other advanced measurements . Existing examples of research infrastructure that already supports many of these “gold-standard” data variables include the USDA Long-Term Agroecosystem Research network, some National Ecological Observatory Network sites, and AmeriFlux sites on cropland and pasture land . Further, the recently launched U.S. Department of Energy ARPA-E SMARTFARM sites have been collecting soil, crop, and GHG fluxes data with even greater spatial and temporal resolutions , enabling a new generation of R&D development such as high-resolution remote sensing monitoring, or novel modeling methods that can capture granular dynamics such as hot-spot and hot-moment patterns of GHG emissions. Tier 1 super sites would enable detailed model calibration and out of-sample validation by virtue of the fact that gold-standard datasets capture whole ecosystem flux , soil carbon flux and stock, plant biomass etc. What would make the Tier 1 super sites more useful is to add paired experiments with detailed measurements for the pairs.

For example,vertical gardening in greenhouse setting up two neighboring sites with one growing cover crop and the other not, and keeping other management practices the same or similar enough, the difference of measurements could provide strong scientific evidences and thus validation data for quantifying the carbon outcome of different management practices. Successful examples of paired experiments with eddy-covariance flux measurements have been demonstrated in rice methane emission using alternate wetting and drying . Super sites also provide further validation for the cross-scale sensed E, M, C variables. Tier 2 – Intermediate sites: This tier includes an extensive number of sites that only have a few key ground measurements but do not have a complete suite of observations as the Tier 1 super sites. Using these ground measurements and also remotely sensed observations, MDF can be conducted, and validation can still be made directly to compare the simulated crop yield, SOC stock and SOC changes with ground observations. When doing model validation at the Tier 2 sites, only basic information about site location and management history will be provided, and the modeling team should report their simulation results for independent comparison with observations. Tier 3 – Scaling sites: This tier includes virtually any site or field that requires carbon outcome quantification. Little or no ground measurements are available at these sites. This tier of sites thus represents the real-world situation for operational use. However, using the cross-scale sensing technologies , all random fields will still have a suite of remotely sensed E, M, C data available to enable MDF and quantify both carbon outcomes and associated uncertainty at all these fields. Model verification at every field is also made possible when extra remotely sensed observations can be used as independent validation data. It is worth noting that Tier 3 almost entirely relies on remotely sensed and/or public-database E, M, C information, which highlights the importance of cross-scale sensing to enable such a new MDF approach. Looking forward, the “System-of-Systems” solution will be the most promising technology for field-level carbon outcome quantification.

One of the biggest advantages of the “System-of-Systems” solution is that it is an inclusive framework that can embrace new technology and has the potential to ingest new scientific discoveries and information, and thus can continue to evolve with the whole scientific community and technology trends. While prototypes of such a “System-of-Systems” solution are emerging for certain crop types and geography , this integrated system consists of several components that are still at their early stages, thus requiring considerable R&D investment by government and industry. Coincidentally, these investments will build the foundation for the next generation of precision agriculture whose scope has been expanded from increasing productivity and efficiency with site specific management , to the integration of sensing, big-data analytics and automation for guiding sustainable farming . However, technical advances alone are insufficient for substantiating the agricultural carbon market or agricultural sustainability more broadly; success will also rely on synergies among citizens, researchers, corporations, NGOs and governments to remove scientific and practical hurdles. First and foremost, we should fully acknowledge that agricultural carbon outcomes are deeply rooted in complex agroecosystems, and a holistic system view of carbon, nutrient, energy, and water cycles strongly coupled with human management should be the guiding principle. Above ground and below ground processes of carbon cycle collectively determine the SOC change , thus only focusing on changes in soil carbon pools while neglecting other critical carbon processes may lead to limited success. The tight connection of carbon cycle with other biogeochemical cycles and water cycle also highlights the importance of soil moisture, soil oxygen and chemical characterization of litter, which links SOC with the GHG emissions . Many unknowns about these above linkages exist . Coordinated research on understanding the holistic carbon nutrient-water cycles for agroecosystems is a priority that could be effectively pursued by leveraging the Integrated Model-Observation Experiment Paradigm . ModEx promotes the idea that models should be developed with the current best knowledge and corroborated with observational and experimental data, and models are then used to identify opportunities for additional field and lab-based research to fill gaps in further understanding system structure and function.

Second, we should use community efforts to develop unified protocols that guide measurements and modeling schemes to understand and reduce the uncertainty of carbon outcome quantification. Such protocols must be established through collective effort to achieve scientific rigor and transparency. Existing efforts led by certification organizations such as Verra and Climate Action Reserve are important and valued, but tend to be simplistic, conservative, and not always well-adapted to the nuances of production agriculture, given the limited empirical data and insufficient MRV tools . To successfully establish public confidence in low-carbon bio-energy feedstock, climate-smart commodities and agricultural carbon credit markets, a concerted effort of more advanced field work, data collection, and modeling assessment will be necessary. It is anticipated that debate will intensify as more disciplines and stakeholders become involved in the new phase of protocol development and validation,greenhouse vertical farming especially when the necessary rigor requires technical sophistication beyond traditional quantification approaches . To foster open and constructive conversations that increase credibility and the public confidence in carbon outcome quantification methods, three principles must be emphasized. First, the quantification uncertainty of field level carbon outcomes must be emphasized, and especially for the market-based instruments, such as climate-smart commodities and carbon credit markets, the uncertainty of the calculated carbon benefits should be reflected in climate-smart commodities’ price premium, or carbon credits pricing and policy design to ensure that the incentivized impact is not over- or under compensated. For example, the standard deviation of a MRV system can be used to discount the value of credits generated . This is an essential requirement for the protocol to be usable, not just a subjective technical preference. Second, validation is the only way to report system-wide uncertainty. No exemption should be made for any quantification tool, even if the tool is widely used or peer reviewed. There are some academic-based model intercomparison MIP efforts that can shed light on how to set up such validations, but given the transaction purpose of carbon credits, a high bar must be set for acceptable model performance. Third, demonstrating performance at the scale of an individual field is critical. Due to the challenges of achieving scalability, some practitioners suggest compromise by focusing on the aggregated accuracy of quantified carbon credit . We argue that aggregated accuracy, which is almost impossible to validate, must come from field-level accuracy. Next, establishing high-quality and comprehensive datasets and inter-comparison infrastructure for developing, calibrating, and validating MRV systems of carbon benefits is essential to building stakeholder trust in these market-based emission reduction instruments. The high-quality and comprehensive dataset to represent the three Tier validation system should ensure site representativeness to include different soil, weather, crop, and management types, and be open-source but compiled under a protocol of community-wide acceptance. An analogy is the Image Net database for computer vision and AI research, with which new algorithms will be bench marked to show their progress in visual object recognition.

Establishing an “Image Net for Agriculture” is certainly more challenging given the complexity of carbon quantification. Due to the often large uncertainty associated with agricultural measurements, protocols for standardized data collection, and processing techniques must be carefully evaluated and imposed. Some long term experiment and observation networks have collected a complete suite of E, M, C variables and have the great potential to provide high-quality and comprehensive data. Lastly, a large number of controlled experiment sites can be used to test the model scalability. These sites often have limited amounts of ground measurements but represent the real-world conditions for operational use. Further investment in high-quality data collection should prioritize experiments that can help understand the carbon outcomes associated with different bundles of carbon-outcome-related practices, such as the combination of no-till and cover crop, as well as measurements that can disentangle the opaque “black box” of complex plant-soil-microbe interactions . In addition, deep sampling of soils beyond the typical surface sampling depths is necessary to accurately quantify the extent of SOC changes and to corroborate estimates by models. Developing cyber infrastructure to ensure archiving and sharing of the scientific data is also highly important and should be an investment priority. Such cyber infrastructure development should be guided by the FAIR guiding principle for the collected scientific data management and stewardship , with a thorough consideration of privacy protection of farmer data. Finally, while our discussion has mainly focused on agricultural carbon outcomes, it is important to note the myriad environmental and economic co-benefits , which in turn can bring further benefits to carbon mitigation programs per se. Some recent case studies have demonstrated that, given the relatively low carbon credit price, participation of farmers may be primarily driven by these cobenefits . The “System-of-Systems” framework proposed in this perspective can be extended to assist the accounting of these co-benefits, and inform sustainable agroecosystem management by holistically studying the often coupled carbon, water, and nutrient cycles and human activities, a topic itself at the frontier of Earth system science. Poverty, often defined as very low socioeconomic status or lack of material wealth, negatively impacts almost every aspect of human biological functioning . It undermines growth and development, compromises basic physiological functions like immunity, intensifies disease, and worsens mental health . Lack of material wealth is a fundamental stressor in humans, both in terms of lack of access to basic needs, but also because of the low power and stigmatized social meanings attached . In studies that treat poverty as a driver of bio-cultural variation, “poverty” is most often operationalized as lack of wealth within the cash economy . Direct measures often focus on assessment of income or purchased material assets like housing materials or vehicles . Other often applied proxy measures are related to consumption or current or predicted participation in the cash economy like occupation or education . Recently, a study by Hadley, Maxfield and Hruschka , clarified that a dimension of agricultural wealth independent from cash economy wealth can show very different associations with human biological outcomes compared to those based in the cash economy. They found in a study of households in several sub-Saharan African countries that success in the cash economy was associated with increased risk of HIV infection, while success in agricultural activities often proved protective against that risk. Here we expand on the proposition that poverty measures giving primacy to the lack of success in the cash economy could overlook a crucial dimension of poverty that is important for understanding associations with well being, specifically the potential buffering role of agricultural forms of household wealth.

Greek peasants turned to vine monoculture, with most of the currant exports now destined for France as well as Britain. The phylloxera crisis in Europe ushered in a third phase of the extension of currant vineyards that lasted from 1878 to 1893. As global demand for Greek currants inflated to unprecedented levels, the monocultural currant-growing region in Greece extended further, well beyond the traditional currant region around the Gulf of Corinth. Currants spread south to the region of Messenia in the Southern Peloponnese, which had never been a currant region before, and by the end of the century, the southern coast of the peninsula had displaced the north as the primary currant-cultivating region. The French market that emerged after the Phylloxera epidemic preferred currants from the southern Peloponnese, because although they were lower quality, they were cheaper, and the lower quality was appropriate for the making of raisin wine.Thus, from the 1860s to the 1890s, the currant-growing region expanded and moved from a system of diversified agriculture to a state of vine monoculture. Nevertheless, currant specialization was geographically limited to the north and west coasts of the Peloponnese and the Ionian Islands of Kephalonia, Zakynthos, and Ithaki. The currant region did not expand to encompass the entire peninsula, much less the whole of Greece. In terms of the total area of the cultivated land of Greece, currant vineyards only occupied about 6% throughout the period of most intensive cultivation—keeping in mind that during this period,hydroponic net pots the Kingdom of Greece added the currant-growing Ionian Islands to its borders, but it also added Thessaly, which was not a currant region.

Despite its outsize role in the Greek export economy, it is important to note where, specifically, the choices were made to switch from diversified agriculture to monoculture, and to currant monoculture, specifically. This is not to say, however, that commercial agriculture was limited to these places, and that the rest of the peninsula remained committed to traditional agricultural practice. Rather, agricultural activities became specialized, intensive, and commercial in various parts of the peninsula, but it took different forms in other regions. Some of these activities were adjacent or supplemental to “currant mania,” such as the specialization in wine grapes, timber production in the mountainous inland regions of the peninsula, and the corresponding industrial activities, making timber into stakes and barrels, and making grapes into wine. Other regions specialized in different agricultural commodities, sometimes for export and consumption abroad, particularly olives and livestock. It is also worth noting that, while the currant zone was geographically limited, other varieties of vitis vinifera were ubiquitous. Unlike currants, the common grape vine is a very versatile crop, and it thrives in a variety of climates and soils.At the same time the currant region was advancing toward currant monoculture, the Peloponnese as a whole was becoming more devoted to vine monoculture. In the currant region, the extension of currant vineyards was accompanied by the extension of other vineyards. In the deme of Patras, the percentage of cultivated land devoted to currants increased from 5% in 1833 to 43% in 1861. In the same period, the percentage of land devoted to other vines increased from 3% to 28%. Thusin 1861, almost 71% of the cultivated land in the deme of Patras was growing vines.The increase in wine production was part of the same trend toward intensification, specialization, and commercialization in Greek agriculture. Wine was primarily produced for household consumption, but wine was also one of the main exports of Greece. The others included olive oil, leather and hides, cocoons, acorns, and figs.The production of these other commodities also increased along with currants. The extension of vineyards and the move to vine monoculture also led to the creation of a small wine making industry in Patras. After the emergence of the market for raisin wine in France, most wine making was done in that country, with raw currants being exported to France to be made into wine there. In Paris in 1890, there were twenty factories for producing wine from currants.However, a local wine making industry did also develop in Patras.

The first attempt to start a wine making industry was in the recovery from the Oidium crisis. In 1858, Wine making A.E. was founded, and operated 16 wine making factories in Patras. Because of the uncertainty caused by dependence on foreign demand, Wine making A.E. tried to create a domestic market for currants to be consumed as raisin wine.98 However, with the recovery of the currant vineyards from Oidium, the imperative to protect the currant industry from the whims of foreign markets faded, and Wine making A.E. failed. In the 1870s, however, Patras did become a wine making center after British and German entrepreneurs invested in the local wine making industry. In 1873, the German businessmen Gustav Klauss and Theodor Hamburger founded a joint-stock company called Achaia which manufactured spirits and red port wines from Greek grapes and currants. Three to four Greek companies also formed to manufacture wine.The currant economy collapsed due to the disappearance of French demand and the emergence of new competitors. First, the demand from France, which proved so crucial to sustaining the extension of currant vineyards in the 1880s, disappeared. French agronomists discovered that grafting European vines to North American roots made them immune to the phylloxera aphid. American vines had grown resistant to the aphid after centuries of co-existence and could thrive even with phylloxera living on their roots. Over the course of the 1880s, American roots spread to vineyards throughout France, and French production began to recover. The area of vineyards in France with American roots grew from 2,500 hectares in 1880 to 45,000 in 1885.100 The recovery of the French wine industry was not immediate, however, as raisin wine made from Greek currants had found a loyal market in France. Currant wine was popular among lower-class, urban consumers who liked it for its sweet taste.

It was also more affordable than domestically-grown French wines and was taxed at a lower rate. Working people could buy currants and make their own wine at home for 5 times less than the price of French-grown wine. Currant wine also kept better than regular wine. French vineyards were recovering, but they faced stiff competition from raisin wines and struggled to regain control of the market.101 When their vineyards were recovering but they were not able to sell their product, French vineyard-owners took to the streets and set up barricades to push for an import duty on raisin wines, and the French government responded with protectionist measures. In 1889, the Chamber of Deputies passed the Griffe Act, prohibiting raisin wine from being marketed as wine, and mandating that all wine made with currants be sold with a label prominently affixed that indicated it was “currant wine.”When this proved ineffective to curb the consumption of currant wine, the next year, the Chamber imposed a manufacturing duty on currant wine of 4s. 8d. per cwt. of currants. This was more effective,blueberry grow pot but currant wine consumption continued. From 1892 to 1896, the Chamber raised the import duty three times, from 2s. 4d. per cwt. to 6s., then to 10s., and finally to 19s. With the 1896 tariff, the French taxes on currant wine amounted to five times the cost of the product itself. In 1897, legislation was also passed to raise the tax on raisin wines to be equal with the tax on all other wines, but the market for currant wine was effectively dead in France by 1896.Currants did not disappear from Greece after the collapse of the currant economy in the 1890s. They remained an important cash crop long after the currant crisis. In fact, in the immediate aftermath of the crisis, currant cultivation continued to grow. In the wake of the crisis, those involved in the currant industry, particularly in Patras, organized to call for state intervention. In 1895, the Greek Parliament passed a plan for state retention of surplus currant production. The state would retain the estimated excess production of currants based on the previous year’s consumption, and these currants would be directed toward promoting the domestic wine making industry. The law required currant exporters to deposit 15% of their inventory at a government storehouse to be sold domestically at reduced rates. In addition, the revenues from these sales would be deposited in a Currant Bank , established in 1899, and the accumulated capital would be used to assist currant growers in the future.112 At first, the retention act succeeded in promoting a domestic wine making industry, and distilleries opened throughout the country. The act thus succeeded in the short term in creating a domestic demand for currants—something that had not existed in Greece before—but the act was amended to prohibit the use of retained currants for wine production. The goal was to compel producers to buy currants at market rates rather than reduced rates, but the additional cost constrained the growth of this new industry.

The retention act, moreover, did nothing address the problem of the overproduction of currants—if anything, it removed disincentives to grow— and currant production continued to rise.The 1903 surplus was huge, and the National Bank of Greece, the Bank of Athens, and the Ionian Bank all had to lend to the Currant Bank. In 1904, a bill was passed that taxed new currant plantations and substituted the export duty on currants with a 15% duty in kind, having the effect of increasing the amount of retained currants.Eventually, an equilibrium was found, and the migration of rural populations alleviated the rural labor surplus. Currant cultivation continued to be strong in the traditional currantgrowing core—Zakynthos, Kephalonia, Patras, Vostizza, and Corinth—which produced high quality currants purchased by Britain for consumption in puddings. This market remained unaffected by the closing of the French market, which preferred lower quality currants from the southern Peloponnese to be made into wines.The newer currant-growing provinces in the southern Peloponnese also continued to grow currants, but on a much smaller scale. Currants never regained the exalted status among Greek agricultural products that they enjoyed during the “golden age,” and a greater segment of the landscape was devoted to other crops such as figs and olives, but currants continued to be a part of the regional economies in the Peloponnese throughout the twentieth century.This chapter has demonstrated that an increase in foreign demand, technical and technological innovations, and land reform policies operated together to deepen the integration of Greek currant production with Western markets and transform normative agricultural practice from micro-ecological specialization to regional monoculture. The next chapter moves on to examine the spatial and ecological dimensions of this monoculture in the Peloponnese, i.e. how landscapes and settlement patterns were transformed to sustain intensive currant cultivation. In the middle of the nineteenth century, the spread of currant cultivation in the coastal plains of the Peloponnese transformed the regional economy and changed this pattern of settlement and migration, redefining the relationship between high villages and coastal hamlets. First, currant cultivation provided the impetus for lowland colonization. During the Little Ice Age climate, land reclamation was difficult and dangerous work. Under these conditions, there had to be a compelling reason to marshal the necessary labor and capital to drain lowland plains. The profitability of currants on the global market in the nineteenth century provided just such an incentive. The spike in foreign demand for Greek currants created the imperative and produced the means to undertake land reclamation and colonize lowland plains in the coastal Peloponnese in order to devote more land to currant cultivation. Moreover, around the middle of the nineteenth century, the Little Ice Age came to an end in the Mediterranean, making the reclamation of land from wetlands much easier .As a result, as Tabak argues, “During the course of the nineteenth century, but mostly gaining velocity from the 1850s, the low landscapes of the Inner Sea were steadily yet inexorably re-colonized.”In the late nineteenth century, there were “massive drainage projects” to turn lowland wetlands into arable land.The further incorporation of Greek agricultural production into global markets combined with a warming of the Mediterranean climate to permit large-scale, permanent colonization of the lowland plains. The dispersed, mountain settlement that characterized the seventeenth and eighteenth centuries in the Peloponnese gave way to large-scale, aggregated lowland settlements by the end of the nineteenth century.

One such strategy was poly cropping or intercropping, whereby farmers planted different crops on the same plot of land. This made the most productive use of a plot of land in all seasons and helped to ensure that even if adverse conditions caused one plot to under-perform the land would still be productive in another season. Olives, cereals, and pulses were harvested at different times, for example, and could be planted alongside one another.Figs mixed well with olives or with vines, so these could also be planted side-by-side.Poly cropping also occurred in household gardens, where cereals and a variety of vegetables were grown together.Another strategy was land fragmentation, meaning rural populations owned small plots of land in different places. This allowed them to spread their risk across different micro-ecologies, so adverse conditions in a given year on one of their holdings did not result in a total loss. Diversification also meant Greek populations were “pluriactive,” meaning they undertook activities beyond agricultural production. They were not simply farmers —they also kept livestock and they engaged in seasonal skilled and unskilled manual labor.Greeks also turned to other resources beyond those they produced themselves. Rural Greek populations knew that they could not depend on agricultural production alone to meet the needs of their subsistence, so they also relied on “marginal landscapes” in order to obtain other resources. In times when traditional sources of livelihood under-performed,fodder system for sale rural populations had to be ready to exploit other resources provided by different micro-ecologies.

Depending on the characteristics of the micro-ecology, there were different alternative sources of food. Lakes, rivers, and the sea could be turned to, for example, for fish, starfish, and eel. Other environments might provide tortoises, fowl, or game. Collecting wild greens, or horta, was a very common strategy throughout the Greek world.The other two imperatives, as mentioned above, were to store and to redistribute. Whenever a resource was produced in excess of the needs of the family at a given time, the surplus could either be stored or exchanged. It could be stored and thus saved for a time when other sources of production under-performed, and then it would buffer against the risk of subsistence failure in the future. Alternatively, it could be exchanged for other useful commodities that were necessary for survival.All of these strategies were developed to maximize the potential for meeting one’s family’s own subsistence needs every year. As such, we can say that subsistence was the norm—it was the goal that every peasant household aspired to achieve. In an ever-uncertain world, rural Greek populations sought to minimize their exposure to the risk that they might fail to marshal all the resources necessary for their survival. Scholarship on the historical ecology of the Mediterranean and on so-called traditional agricultural practice stumbles over the nineteenth century and collapses in the twentieth century. Horden and Purcell acknowledge that their model of the Mediterranean as a patchwork of shifting, interdependent micro-ecologies is difficult to apply in the modern period. They acknowledge that “Mediterranean history” ends sometime in the nineteenth or twentieth century, although they are uncertain when the shift occurred and what caused it.Grove and Rackham run into a similar problem.

They argue forcefully against what they call the “ruined landscape” theory—that the Mediterranean landscape was more lush and fertile in ancient times, and modern Mediterranean people degraded the land with their unscientific use of it. Their thesis is that human actions are not to blame for environmental changes in Mediterranean Europe. Mediterranean ecologies are resilient and constantly changing; fires and erosion are natural aspects of the Mediterranean and not a result of human misuse; “badlands” is a misnomer; and a lack of forest is not the same thing as deforestation. This argument certainly has its merits, but Grove and Rackham downplay the significant changes that have occurred since the nineteenth century. The literature on the historical ecology of the Mediterranean depicts a timeless, unchanging Mediterranean region from antiquity to the modern era. In this way, it replicates a pitfall of the related historical and anthropological literature on Mediterranean agricultural practice. If the Mediterranean ecology was unchanging, so, too, were human interactions with it. Scholars studying the ancient past have used ethnography of contemporary Greece to supplement literary sources and material culture. To better understand ancient farming practices, for example, they studied contemporary farming practices. John Campbell and Ernestine Friedl pioneered the field of ethnography of Greece, conducting field research in rural settings in Greece in the 1950s and recording their observations of rural Greek populations’ concepts of honor and shame, gender roles and family structure, and agricultural practices.There has been a tendency to treat these studies a historically as representing “traditional” Greek society, as if their descriptions of Greek village life could be applied equally to the 1950s, the 1850s or the fourth century BCE.

Susan Buck Sutton has called this approach “survivalism,” in which, “The nineteenth or twentieth century existence of a folk song, ceramic vessel, or farming technique similar to that of antiquity has been taken as proof of unbroken continuity.” This approach has been replicated in other disciplines, such as ethno-archaeology.It also fits well with Greek nationalist historiography, folklore studies, and Romanticism—endeavors for which an unbroken Greek cultural continuity from ancient times to the present is expedient. Ethnography has certainly been a useful way to fill in the gaps left by the limitations of other sources. Studying the ancient past through analogy to the present, however, has had its drawbacks, and more recently, this approach has come to be challenged. As Paul Halstead has argued, “Emphasis on relatively timeless constraints… of environment , technology and perhaps know-how has encouraged uncritical extrapolation to antiquity. Traditional practice was highly variable, however, and demonstrably shaped also by medium-term historical contingencies and cultural preferences and by short-term tactical decision-making.”It is now recognized that the Greek countryside and Mediterranean farming practices were contingent on a multitude of factors. As Halstead argues, there has been a tendency to overgeneralize Mediterranean farming practices, and there was, in fact, a great diversity of practices. Different regions in the Mediterranean imposed different material constraints—e.g. based on climate, terrain, and quality of soil—but many more factors also influenced farming practices. Individual factors also mattered a great deal, such as one farmer’s specific production goals, his strength and skill, the size of his plots, and the distance of his plots from his home. As Halstead writes, “Individual farmers often do things differently, because they are more or less industrious, conservative, proud, burdened with dependents to feed, or blessed with “hands” to help.” Based on these factors, individuals made different choices. Rich farmers with lots of land left more of their land fallow; poor farmers farmed every inch they could afford to.Finally, cultural factors need to be accounted for. Diversity in farming practice also results from different cultural “ways of doing.” There were many local customs that influenced farming practices, and not all of them were grounded in practical considerations.In sum, ethnography is a useful tool for postulating about farming practices in the past, but only when it is considered alongside other sources and when the contingencies of rural Mediterranean life are kept in focus. Among the larger contingencies that affected Mediterranean ecology and agriculture over the medium-term were economic, demographic, and climatic changes. As I examine next,fodder growing system the influence of these factors needs to be taken into consideration in order to understand the changes that occurred over the course of the nineteenth century. The dynamism of the Mediterranean countryside is well illustrated by an examination of long-term changes in settlement patterns, crop regimes, and climate. In the fifteenth and sixteenth centuries, the population of the Peloponnese—and of the Mediterranean basin in general—was concentrated in the lowland plains, which were the center of economic activity, and the main crops were cereals, especially wheat. Then, beginning in the middle of the sixteenth century and lasting until the middle of the nineteenth century, a new settlement regime became dominant as populations shifted away from low-lying plains and became more concentrated in the hillsides and mountains of the Mediterranean. Grain cultivation moved out of the Mediterranean, and the Mediterranean returned to the cultivation of its “civilizational crops,” i.e. vines and olives.The shift of the economic and demographic center of the Mediterranean from its low lying plains to its hills and mountains occurred at the interface of two larger processes. The first was a drop in the annual average temperature, often referred to as the Little Ice Age.

Estimates vary, but this Little Ice Age lasted roughly from the middle of the sixteenth century to the middle of the nineteenth century in the Mediterranean. The Little Ice Age was a period of “several phases of cool summers and cold, snowy winters.”During this period, there were also several clusters of extreme weather events in Mediterranean Europe, including floods and out-of-season rain, droughts, and especially cold winters—the worst decades were the 1540s, the 1560s to the 1640s, the 1680s to the 1710s, and the 1810s. These weather events often resulted in failed harvests, frequent famines in much of Europe, and favorable conditions for certain diseases, such as malaria and plague. The cause of the Little Ice Age is unknown. Alpine glaciers advanced at times during this period due to successive heavy snowfalls followed by cool, late springs—this could explain extreme weather events in the Alpine Mediterranean, but not in the southern Mediterranean. Other possible explanations include volcanic eruptions, sunspot minima, a shift in the anticyclonic belt of the Northern Hemisphere similar to the one that caused the Medieval Warm Period that preceded the Little Ice Age, or some combination of these factors. Whatever the cause, this change in the climate of Europe and the Mediterranean made the cultivation of lowland plains more difficult and less predictable. In Mediterranean Europe, the colder average temperature meant a shorter growing season in the summer and a wetter climate overall. Due to increased fluvial discharge, the best croplands in the low-lying plains were waterlogged for a longer segment of the year. As Faruk Tabak has written, the lowland plains “were largely deserted and taken over by swamps, wetlands, and reeds—not to mention the fauna that thrived in such environments: the mosquito, snakes, storks, and lizards.”During the Little Ice Age, making wetlands suitable for habitation and cultivation was an expensive, labor intensive task. Drainage works needed constant upkeep, and they could be swiftly undone by an unexpected deluge. Furthermore, the risk of malaria made it a dangerous endeavor, and land reclamation needed to be done on a sufficiently large scale to eliminate the risk of malaria from nearby fields. This was the world that Braudel described in The Mediterranean and the Mediterranean World in the Age of Phillip II in which he wrote, “To colonize a plain often means to die there.”With the beginning of the Little Ice Age, permanent settlements moved from lowlands to highlands, and temporary settlements , “mushroomed throughout the basin.”The second factor that caused population to become more concentrated in upland areas was the transplantation of American crops to Europe and of old world crops to the Americas—a process often referred to as “the Columbian exchange.”In the seventeenth century, landand labor-intensive “oriental” crops, especially cotton and sugar, moved out of the Mediterranean and to the Americas, where there was plenty of land to exhaust and slave labor to exploit. From the 1650s on, sugar production shifted from the Mediterranean to the Atlantic , and sugar production was much greater there. In the fifteenth century, Cyprus exported a few hundred tons annually; in the seventeenth century, Jamaica exported 72,000 tons annually.In addition, grain production moved out of the Mediterranean and was relocated to large estates in Eastern and Central Europe, also with coerced labor. In the sixteenth century Mediterranean, the grain trade was 100,000 to 200,000 tons. In the seventeenth-century Baltic, the grain trade was 600,000 tons.Meanwhile, in the Mediterranean, American crops were being introduced to replace sugar, cotton, and grains. The American crops that were introduced—e.g. tobacco, maize, and beans—could be grown at higher altitudes in the Americas, and they similarly thrived in the highlands of the Mediterranean basin.As populations were forced to relocate to higher altitudes by the inhospitable conditions of the Little Ice Age, the crops that justified lowland settlement in the first place disappeared from the basin, and upward relocation was facilitated by the availability of new crops that thrived at higher altitudes.