Tag: greenhouse vertical farming

For instance, Pinus nigra ssp. laricio adults have been observed to follow an isohydric strategy, whereas seedlings in a glasshouse experiment did not . Although it is more complicated to impose drought treatments on adults, drought experiments have been carried out on adult trees using networks of rain shields/ gutters to intercept precipitation and direct it away from the trees . This water can also be re-directed to other plots to create ‘well watered’ treatments. For the most part, these studies have been carried out on natural populations. However, if they were coupled with provenance study plantings, one could test for population or genotypic differences in adult drought response. Likewise, apart from some long-term provenance studies , most experiments span a few days to a few months. In order to investigate drought resilience and legacy effects, more multi-year studies are needed.The length and intensity of drought can affect which trait combinations result in greater fitness. In Section IV.1, we mentioned the great diversity of methods used to induce or measure drought stress treatments in gene expression studies. The same diversity is found in G2P and provenance studies as well. There is a need to assess: whether environmental treatments roughly match the range of conditions in the environments in which the target species does or might grow; how environmental treatments relate to plant stress measures ; and whether traits, responses or genotypes associated with drought tolerance in the glasshouse or laboratory predict performance in the field. In addition, studies testing longer term drought treatments are lacking, as are those that explicitly test variable combinations of drought length and severity.

Future work should address these gaps.In most of the genetic studies cited above,u planting gutter a relatively high proportion of the genes expressed or linked to phenotypes or environmental gradients of interest either have unknown or poorly defined functions. Behringer et al. , for instance, found that, of the 832 transcripts analyzed for gene ontology, 538 either had no database hits or could not be assigned to a biological process. Although this could be partly addressed with further studies intraditional model organisms, such as Arabidopsis, analysis of loblolly pine and Norway and Sitka spruce genome sequences suggests that there could be thousands of conifer-specific gene families . This shortcoming must be addressed by further development of model systems in conifers.The tomato is a functional genomics model for fleshy-fruited species and is one of the most popular and economically important crops globally . However, storage at temperatures below 12.5°C followed by rewarming to room temperature, compromises fruit quality, hampering the post harvest handling of this commodity . This cold-induced damage to the fruit called post harvest chilling injury may only be detectable as a loss of flavor, or in severe cases, as fruit spoilage, the extent of which depends on the storage temperature, length of exposure, genotype and fruit developmental stage . The progression of PCI in fruit tissues is complex. It is marked by a loss of selective membrane permeability, increased solute leakage, reactive oxygen species accumulation and metabolic dysfunction . After the fruit is transferred to room temperature for rewarming or reconditioning, higher respiration ensues within days , and within a week, secondary symptoms such as uneven color formation, surface pitting, water soaking and decay are visible . Symptoms are more intense in green compared to riper fruit, since maturation processes are disrupted by chilling . Because of the negative effect on tomato quality and shelf-life, our goal is to better understand PCI development and regulation in this species. Some aspects of the disorder or approaches used here may be relevant for other PCI-sensitive species.

First, we investigated the spatial and temporal evolution of PCI in the whole tomato fruit using MRI. Most studies of tomato PCI have focused on the pericarp, ignoring the internal tissues, which can account for 30% and 70% of the fresh mass of round and cherry tomatoes, respectively. Tao et al. , investigated changes in chilled ‘Micro-Tom’ fruit using non-invasive MRI. They showed that the columella and locular region differed from the pericarp in their response to cold, which has implication for understanding the underlying causes of PCI. The fruit in that study were subjected to a severe cold stress , since this genotype is not as sensitive to chilling temperatures as many commercial varieties . Further, only one developmental stage was chosen . It is not known if their findings are applicable to other cultivars, storage conditions or maturation stages. Second, we investigated if 5-azacytidine could alter PCI. This chemical inhibits DNA and RNA methylation , epigenetic modifications that regulate gene expression, in response to developmental and environmental stimuli in a tissue-specific manner . DNA methylation is a key regulatory process for tomato fruit ripening ; injecting AZA in round tomato fruit accelerated ripening . It was shown that chilling-induced reductions in red fruit volatiles correlated with methylation of key ripening genes. Co-regulation of the ripening and cold response regulatory networks in fruit undergoing chilling stress seems likely . Since differential methylation is essential to both processes, we wanted to determine if AZA could influence PCI symptoms in tomato fruit. In this study, two questions were asked: 1) is it possible to detect spatio-temporal differences in chilled tomato fruit differing in maturation stage, and temperature × time of storage by low-resolution MRI?, and 2) would AZA influence PCI response? For the former, we used commercial cherry tomatoes and mild to moderate chilling stress. For the latter, fruit were injected with AZA weekly in order to detect changes in PCI by methylation , specifically on respiratory activity. Fruit from a commercial cherry cultivar and the functional genomics model ‘Micro-Tom’ were used in this study.At this developmental stage in ‘Sweet 100’, the pericarp, columella and locular tissue showed a differentiated pattern in terms of their D-values after 7 days of chilling . Values were highest in the pericarp followed by the locular tissue and columella. Similar patterns were seen in freshly-harvested breaker fruit .

These three tissues have heterogeneous transcriptional and metabolic profiles due to their distinct origin and functionality . This likely contributed to the distinct D-values observed. When D-values for each region were compared as over each chilling period,planting gutter no changes were observed except for the columella in fruit held at 5°C. Unchanged D-values may be due to cold-induced reductions in free water movement within tissues, and pectin solubilization . Fruit exposed to warmer temperatures, i.e., after storage at the control temperature for 7 days, or after transfer from the cold to 20°C, showed more dynamism in D-values. The different tissue fractions, which had distinct D-values during chilling, changed and became more similar when exposed to warmer temperatures . These non-chilling temperatures may have allowed ripening and other physiological events to take place, leading to these changes.Figure 3A shows the D-values of ‘Sunsugar’ ripened fruit. These data, gathered from breaker, pink, and red fruit immediately after harvest, suggest that as ripening progresses, the D-values of the columella and locular region become more similar . Ripening increases the proportion of free water and metabolites within tissues, due to liquefaction of the locules and breakdown of the structural components of the cell . These changes may have underscored the increased D values seen here, and in other studies . A similar occurrence was seen when red fruit was stored at 2.5°C for 5 days . When D-values for each region were compared over time, there was no significant difference. Tissue liquefactionin red fruit was so extended as a consequence of ripening, that cold did not generate any detectable increase by the MRI, or did not increase membrane leakage since it was already fluid. The observations of pink fruit stored in the cold and then rewarmed are less clear. Both chilling-induced damage during low-temperature storage, and ripening-related tissue deconstruction during rewarming would lead to increased membrane permeability and D values , thus making it difficult to attribute higher D values to one or the other biological phenomenon. There are some points to emphasize with respect to the data when analyzed across cultivars and conditions. First, pericarp D-values did not vary as much as those in the columella and locular regions . Second, there was a weak correlation between MRI derived values for the pericarp and the physical changes caused by cold, visible on the pericarp e.g., poor color development, pitting and decay as reported by the CII data . In contrast, there was more synchrony for the columella and CII which is similar to the data published by Tao et al. . Surprisingly, the locular fraction showed a similar r-value to the pericarp when CII was considered. Therefore, other mechanisms besides the increased water mobility we were able to detect under the experimental conditions used, may have a higher contribution to the development of chilling induced external symptomatology. Third, different D-values were recorded in the three tissues as ripening progressed: they decreased in the pericarp, increased in the columella and were unchanged in the locular tissue , exemplifying the unique response of each tissue-type.

Fourth, MRI could only detect changes after transfer of chilled fruit to room temperature. Loss of membrane selective permeability due to a cold-induced membrane phase transition was not sufficiently advanced to produce detectable increases in free water mobility during cold storage. This supports the view that, increased membrane permeability is unlikely to be one of the earliest events in PCI response, but occurs at a significant rate during rewarming .Fruit undergoing PCI normally exhibit a transitory burst of CO2 when transferred from chilling to room temperature, which acts as a reliable marker for the early stages of cold injured tissue . If AZA-treated fruit show differences in respiratory activity after cold stress compared to the water-treated fruit, this could beindicative of an effect of methylation on PCI. Different responses were observed across varying cold stress in ‘Micro-Tom’ and ‘Sun Cherry’ and are described in turn.AZA affected respiration in fruit stored at both cold and control temperatures across the rewarming period. After 21-days at 2.5°C, AZA led to a lower respiratory rate compared to the water-control fruit during reconditioning , suggesting that AZA might moderate chilling injury in ‘Micro-Tom’. In contrast, at 12.5°C, AZA-treated fruit had higher respiratory rates compared to the water-treated fruit after storage . This effect was likely a result of accelerated climacteric respiration caused by AZA-accelerated ripening . AZA may have varying effects in different conditions, which is consistent with the fact that methylation patterns are diverse across developmental stages with various environmental stimuli .This cultivar was more susceptible to PCI than ‘Micro-Tom,’ and may show a different response to AZA-treatment. In all experiments, an increase in respiration was observed after transfer of fruit to 25°C following cold storage . Effect of AZA was evaluated across reconditioning period . To understand the effect of AZA on respiratory rates in the absence of chilling stress, fruit held at 12.5°C were examined over the entire storage period. AZA treatment led to higher respiration after 14 days , likely due to accelerated ripening. In contrast, water injected fruit showed increases in respiration later – after 21 and 28-day storage . This may be due to a ‘delayed’ climacteric response relative to that in the AZA-fruit. AZA affected the respiratory activity of post harvest chilled fruit after reconditioning. As expected, fruit stored at 2.5°C exhibited a higher respiratory burst than those held at 5°C, while it was minor in fruit at the control temperature , indicating severe chilling injury at lower temperatures . Unlike ‘Micro-Tom’, AZA had no effect on ‘Sun Cherry’ fruit exposed at 2.5°C for 21 days or less, nor fruit held at 5°C for 7 days . AZA did influence fruit respiration after storage at 2.5 or 5°C for 28 days . Extreme fungal growth on fruit upon rewarming made it hard to further evaluate effect of AZA on respiration in ‘Sun Cherry’ .Plants have been transported around the world for centuries, as agricultural commodities, ornamental species or inadvertent contaminants of imported materials. Naturalized plants are those that have spread out of cultivated areas, including gardens, into more wild areas, and invasive plants are the subset of naturalized species that cause ecological or economic harm. In general, only a small proportion of plants introduced into a new region have been invasive plants.

Nomad Bioscience has reported successful substitution of the agroinfiltration step with “agrospray,” a technique in which a suspension containing the Agrobacterium inoculant is admixed with a small amount of surfactant and sprayed onto the leaves of host plants. This approach eliminates the necessity to grow plants in containers , a requirement imposed by the mechanics of the vacuum infiltration treatment in current procedures. Concomitantly, it also eliminates the cost of setting up and operating commercial-scale vacuum chambers, robotic tray manipulators, biomass conveyer systems, and so forth. Thus, this new approach should enable large-scale field inoculation of plants with agrobacteria and the production of bio-logics with more favorable economics. While we modeled the costs of producing cellulases via the agrospray approach, the sheer volume of enzymes needed for commercial-scale cellulosic ethanol processes necessitated a large investment in inoculum production infrastructure, including multiple fermentation trains and associated processing equipment. Further, the most efficient method of inoculating large areas was by aerial spraying, a procedure that not only entailed higher cost but that would also face regulatory uncertainties over spraying GM bacteria. We opted instead for an alternative model using trans genic N. tabacum plants, each line of which carries an ethanol-inducible gene for one component enzyme of the cellulase complex. Synthesis of the cellulase is triggered by application of a dilute solution of ethanol onto the leaves,grow table a process that has been demonstrated in small scale using a double-inducible viral vector.

We assumed that the dilute ethanol solution would be applied via ground irrigation systems that are currently used in agricultural practices, instead of aerial tankers. It was also assumed that the ethanol would be taken off as a side stream from the associated ethanol production facility that uses the cellulase enzymes. In so doing, we obviated the need to produce multiple inocula of GM bacteria and deliver them via aerial spraying. We were also able to model higher biomass density as well as higher expression yields of the enzymes in planta. These changes resulted in multiple economic benefits and were therefore adopted in our calculations.Issues that are important in PMP, such as mammalian-like glycosylation or other post translational modifications, high purity, or specific formulation, are not relevant in the manufacture of cellulases and hence we modeled the use of conventional Nicotiana species in the production of the several enzymes necessary for complete saccharification of feedstock.In this case study, we modeled the use of stable transgenic N. tabacum varieties, each modified to express one cellulase protein upon induction with dilute ethanol. The process is based on inducible release of viral RNA replicons from stably integrated DNA proreplicons. A simple treatment with ethanol releases the replicon leading to RNA amplification and high-level protein production. To achieve tight control of replicon activation and spread in the non-induced state, the viral vector has been deconstructed, and its two components, the replicon and the cell-to-cell movement protein, have each been placed separately under the control of an inducible promoter.

In greenhouse studies, recombinant proteins have been expressed at up to 4.3 g/kg FW leaf biomass in the ethanol-inducible hosts, but seed lines for field application have yet to be developed. In our modeling, we assumed that each transgenic line would have been already field tested and available for implementation. We also assumed that large-scale stocks of each transgenic seed would need to be produced and have included this unit operation in our cost calculations. Because cellulases are needed in different ratios to effect saccharification of different feed stocks, we assumed that seeds would be mixed at the appropriate ratios and that the seed mixtures would be planted directly in the field. At maturity, what one would expect is a field of plants representing all the needed cellulase classes in the appropriate ratio for the intended feed stock. The current method of hydroponic cultivation of seedlings for transplantation to open fields, a common commercial tobacco cultivation practice to ensure germination and plants with good leaf size and quality, was substituted by direct seeding for more favorable economics. For example, traditionally tobacco may be grown at 12,000–16,000 plants/ha depending on variety. Higher-density seedling production for nontraditional uses of tobacco has been reported, targeting planting densities of over 86,000 plants/ha. While transplanting ensures germination and quality, there is an economic limit to the scale at which it can be deployed with highly cost-sensitive AI, leading to interest in direct seeding practices. Experimental high density cultivation studies via direct seeding have reported 400,000 to over 2 million plants/ha and biomass yields exceeding 150 mt/ha. Our modeling included these higher-density practices to determine economic impact.In contrast to typical PMP products, the cellulases would not be extracted after accumulation; rather, the plants would be mechanically harvested and transported to a centralized facility for silaging and storage. Since the cellulase enzymes need to be continuously supplied to the saccharification process in the bioethanol plant and the harvested tobacco is only available for a limited period during the year, the silage inventory would increase during the tobacco-harvesting period and would decrease during the fall/winter.

Cellulase activity in the ensilaged biomass is expected to be stable during the off-season storage. For feedstock conversion, cellulase-containing biomass would be mixed with pretreated lignocellulosic feedstock under controlled conditions to effect saccharification. Although not considered in this economic analysis, this feedstock replacement could also reduce corn stover feedstock requirements and associated costs. After separation of solids, the sugar solution would be fermented conventionally into ethanol, followed by distillation. The overall process we modeled is based on the US National Renewable Energy Laboratory process described by Humbird et al, with substitution of fungal cellulase production in the NREL model by the cellulases stored as silage described herein. Design premises for this process, specific assumptions used in modeling,ebb flow table and the resultant cost calculations are presented .Table 3 shows the total capital investment and annual operating costs for the plant-made rBuChE facility at an expression level of 500 mg/kg FW plant biomass . The annual operating costs are shown with and without facility dependent costs to simulate a new facility and use of an existing facility, respectively. Table 4 shows the resulting rBuChE cost per dose for both cases. Table 3 shows the breakdown of the capital investment and operating costs for the plant-made rBuChE and indicates that the unit production costs are estimated to be about $234/dose if facility dependent costs are not included in the annual operating costs or about $474/dose if these costs are included. Most of the capital cost and a significant portion of the operating costs are associated with the recovery and purification of rBuChE. Our base case assumed rBuChE expression of 500 mg/kg FW because that is a target expression level in ongoing research at several institutions. If a currently achievable level of 100 mg/kg FW is used instead , the costs increase to $1,210/dose and $430/dose when including and excluding facility dependent costs, respectively. In any scenario examined, the production costs in plants are significantly lower than the estimated production costs for blood-derived BuChE . We recognize that additional modification or formulation of the plant-produced enzyme might be necessary or desirable prior to adoption for human use and that such additional modifications would increase the cost of the AI. For example, Geyer et al. reported improved pharmacokinetics of PEGylated plant-produced BuChE relative to the nonmodified enzyme. However, because consensus on the preferred options for modification has not yet been reached, we omitted these additional steps from our calculations.The following premises and assumptions were used for evaluation of cellulase bio-manufacturing in open fields. Due to the fact that this process is specialized and due to the scale and input requirements of a modern bio-fuels operation, our analysis included the construction of a new, dedicated manufacturing facility to provide the required cellulase enzymes for a large scale cellulosic ethanol facility . Figure 4 shows the process operations required for cellu lase enzyme production on a per-batch basis. The flow sheet on the top shows the blending tank needed for preparation of the ethanol induction solution to be applied in the field, and the flow sheet on the bottom shows the transport and storage operations following harvest of the transgenic tobacco.Table 6 shows the total capital investment and annual operating costs for the production of 2.87 million kg of cellulase enzymes per year at an expression level of 4 g cellulase/kg FW tobacco biomass and a plant density of 130 metric tons of biomass per hectare per year.

The table also indicates the corresponding costs obtained from the JBEI model for fungal fermentation-based production of approximately the same amount of cellulase enzymes per year . For the base case study, the plant-based system results in a >30% reduction in unit production costs for the cellulases as well as an 85% reduction in the required capital investment. For the plant-based cellulase production system, the major contributors to the unit production cost were the costs associated with tobacco cultivation , the costs associated with ethanol spraying , followed by the costs associated with ethanol dilution, transporting and storage , and seed costs . The differences in total capital investment and annual operating costs for the two cellulase production platforms are not surprising, since the fungal fermentation area alone requires twelve 288,000-L fermenters along with the seed train necessary to provide the inoculum for the production fermenters. The differences between the two systems would be expected to be even larger if the total capital investment included additional factors for associated piping, instrumentation, insulation, electrical facilities, buildings, yard improvements, and auxiliary facilities because these would be reflected in the facility dependent component of the annual production costs. Figure 5 shows the effect of biomass density on the unit production costs for cellulase enzyme using the ethanol induced tobacco system and indicates, as expected, that the cost of goods decreases as tobacco biomass density increases. In agronomic studies with field-seeded tobacco cultivated at high density, biomass yields exceeding 150 mt/ha have been achieved; higher field densities may be possible with selected varieties and specialized agronomic practices.At the eastern boundary of the Sahel lies the Greater Horn of Africa , a region of northeastern Africa with highly food-insecure countries that are particularly vulnerable to interannual and decadal swings in precipitation totals . Both the GHA and Sahel receive the bulk of their precipitation during the June–September boreal summer season. These regions experienced a significant decline in JJAS precipitation during the 1970s and 1980s due to anomalous warming of the South Atlantic and Indian Oceans and subsequent shifts in moisture transports and upper-air flow . Following the 1980s, warming in the North Atlantic appears to have caused a precipitation recovery throughout much of the Sahel . In the GHA, however, the extent of post-drought recovery is unclear. Recent studies suggest drying over GHA may have continued into the 2000s , but the cause of this potential drying and decoupling of precipitation trends in the GHA from those of the Sahel remains unexplored. Previous studies have identified a variety of drivers of JJAS precipitation and drought in the GHA. While JJAS wind trajectories toward the GHA are quite variable from year to year, the rainforest region of the Congo Basin appears to be the main moisture source to Sudan and much of the Ethiopian Highlands, and the Indian Ocean is the main moisture source for eastern portions of Ethiopia and Kenya . South of the center of the North African surface low, deep convection and enhanced moisture transport from the south and west fuel monsoonal precipitation during JJAS in the Sahel and GHA. Historically, for both the Sahel and GHA, the primary driver of interannual and longer-term variability of summer precipitation is the north-south displacement of jets, zone of maximum convection, and southern boundary of the thermal low over northern Africa , all of which appear to be influenced by tropical sea-surface temperature anomalies . Some research also suggests that increased tropospheric aerosol concentration works to suppress the northward migration of the JJAS rainbelt into northern Africa, potentially reducing precipitation in the GHA . Further, relationships exist between the strength of the Indian monsoon and GHA precipitation . Overall, drought in the GHA tends to occur when there is a reduction in the amount of moisture reaching the GHA from the tropical Atlantic Ocean and Congo Basin region.

From this information, we examined fluctuation patterns that could exist specific to a region or crop category and linked the information with the main source of the lowest profit. Information presented for this topic was obtained from Questions 9, 10, and 11 . Risk Management examined farmers’ perceptions of risk and, in particular, the extent to which risk management tools are available and used. Respondents were asked to rank ten risk sources in order of importance and eight risk management tools in the order of preference. For each risk management tool, the survey also asked about its availability and whether it had been used by the farmer. Also included was information on their receipt of government disaster payments or loans. This section used data from Questions 12, 13, and 14 . Crop Insurance was one of the risk management tools covered in the previous section, but it was then given more extensive coverage. This section summarized in formation on respondents’ history of crop insurance purchases, reasons why they did or did not purchase crop insurance, and suggestions for improving the role of crop insurance. Information presented includes the mean rank ing and distribution of ranks. The relevant survey section for this data was Questions 15 through 22 . Financial Characteristics deals with off-farm income, gross agricultural sales, assets, and debts to provide the distributions of these variables and examine the existence of any systematic distribution patterns. Questions 23, 24, and 25 in the survey were relevant to this section.

Crop diversification is well recognized as a risk management tool . However, little information is available concerning the extent of diversification or the mix of crops used in diversification by horticultural producers. As a risk-reducing tool,mobile vertical farm crop diversification plays a role in pricing crop insurance and is likely to be incorporated as a discount factor in future crop insurance premiums. To implement degree of diversification into the crop insurance premiums structure, decision makers need to know the extent to which crops have been diversified. This section sheds some light on the issue. Figure B1 shows the share of fruit/nut and vegetable farmers who grew a single crop. Seventy percent of fruit/ nut farmers were single-crop growers as opposed to 26percent of vegetable farmers. This implied that crop di versification was more common for vegetable growers than for fruit/nut growers, which was consistent with our expectation that diversifying into multiple crops is more manageable for annual crops than for perennial crops. The tendency toward single-crop production, however, varied by crop. For example, for fruits/nuts the share of single-crop farmers ranged between 35 and 83 percent, depending on the crop. As shown in Figure B2, grapes were most commonly a single crop , while stone fruits were least frequently so . Table B1 presents the diversification patterns and mean acreages. The patterns and extents of diversification for fruit/nut and vegetable farms were very different. Of the 30 percent of fruit/nut farms that were diversified, most were diversified with other fruit/nut crops. However, of the 74 percent of diversified vegetable farms, only 26 percent were diversified using other vegetable crops; 48 percent were diversified with crops in other categories. This indicated that fruit/nut farmers rarely diversify into other crop categories and that diversification across crop categories is more common for vegetable farms, particularly with field crops.

Furthermore, even among the growers who diversified within their own crop category, the scope of diversification was smaller for fruit/nut farming, as indicated by the average number of crops, 2.56 for fruits/nuts and 3.59 for vegetables . Table B1 also presents mean acreages. Note that the acreage figures in the table are for land that was planted in fruits/nuts or vegetables only. We did this to exclude often extensive field-crop areas and to examine the scale of farmers’ operations for their primary crops relative to various patterns of crop diversification. A cursory observation of the acreage figures indicated that primary crop acreage increased with crop diversification for both fruits/ nuts and vegetables . Also, farms that diversified within a crop category were relatively large. We revisit this issue with more detailed vegetable data later in this report. Table B2 shows the pattern of crop mix for fruit/nut farms, which are diversified predominantly with other fruit/nut crops. The table lists the two types of crops most commonly used for diversification in each subcategory. Judging by the percent of farmers, growers of berries, citrus, stone fruits, and tree nuts have made substantial use of same-category crop diversification. For tree nuts and stone fruits, the diversification patterns were symmetric with substantial cross-diversification between the two groups. The diversification trends for citrus and tropical crops were interesting. While 66 percent of sampled tropical crop growers diversified with citrus, only 28 per cent of citrus farmers diversified with tropical crops . We now turn to vegetables. Table B3 summarizes the pattern of diversification for farmers who grew only vegetables and shows the distributions of those farmers by the number of vegetables grown. While half of the vegetable-only farmers produced a single crop, 9 percent produced more than six different vegetable crops.

When we shifted from all vegetables to the subcategories, diversification patterns varied considerably. This was illustrated with Groups V2 and V5, which showed the highest and lowest levels of diversification. Table B3 also provides mean vegetable acreages for vegetable-only farmers. There was a tendency for farmers with more acres of vegetables to grow a larger variety of vegetable crops, suggesting that large-scale commercial farms engaged in more diversified vegetable production. In other words, the “scope” of diversification was positively related to the scale of the operation. This report does not include a discussion of crop diversification for ornamental crops because of a lack of information. The finest level of diversification we could investigate with the data for ornamental crops was diversification patterns across the three subgroups in the category: floriculture, nursery products, and Christmas trees. Our data indicated that ornamental growers rarely diversified across these groups. Organic farming information is summarized in Table B4. The table combines acres of “organic” and “transitional-organic” plantings and presents the combined area as “organic acreage” . Table B4 shows that 14 percent of vegetable growers practiced organic farming, compared to 6 percent of fruit/nut growers, although organic fruit/nut farms were more numerous. Most organic farmers also grew conventional crops and, on average, they devoted more land to conventional production than to organic production.This section summarizes the survey results on types of output use , marketing channels, and types of operations . Figure C1 shows the distribution of farmers by type of use for their fruits/nuts and vegetables . The two types, “mainly fresh” and “mainly processing,” were defined to include cases in which more than 80 percent of output volume was designated to the listed use. For fruits/nuts,vertical farming racks 71 percent of farmers were characterized as mainly processing and 23 percent as mainly fresh. These figures were almost re versed for vegetables—67 percent of vegetable farmers specialized in fresh-use crops and 26 percent in processing-use crops. For both fruits/nuts and vegetables, only 7 percent of farms supplied both fresh and processing uses . This implied that production of fruits/nuts and of vegetables in California tends to be specialized for either processing or fresh use.4 Also, these figures were consistent with the common observation that, for both vegetables and fruits/nuts, specific uses dictate the varieties grown. For example, Cling peaches are typically destined for canning and the Roma variety of tomatoes is usually made into paste. Relevant marketing channels are determined by whether the crop goes to the fresh market or for processing since the two uses require different post harvest handling techniques. Once harvested, processing crops are shipped directly to a processing plant. Fresh-use crops are usually sorted, packed, and refrigerated before being shipped to wholesale or retail buyers. This implies that specific marketing channels emerge to accommodate the post harvest handling required for each use. Figure C2 lists the marketing channels available for processing crops and the share of farms that used those channels. For fruits/nuts, marketing cooperatives and contracts with a processor were the most widely used marketing channels, accounting for 90 percent of the farms. How ever, for processed vegetables, marketing cooperatives played a relatively small role. Instead, contracts with a processor arranged at a predetermined price predominated.

While contracts with processors were an important marketing avenue for both the fruit/nut and the vegetable categories, the patterns of pricing arrangements with processors were distinctly different. For fruits/nuts, contracts with and without predetermined prices were almost equally important , whereas for processed vegetables, contracts with processors were mostly arranged under predetermined prices .Given the importance of processing use for fruits/nuts, we further investigated their marketing channels by disaggregating the category and looking at subgroups of the crop, as shown in Table C1.Cooperatives were especially important for citrus crops and tree nuts , and predetermined price contracts were particularly prevalent for grapes . The bulk of the grape growers produced wine grapes and, according to a recent survey, 90 percent of wine grape growers in California have either written or oral contracts with wineries . Overall, the data in Table C1 underscored the prevalent role of contracts in the processed fruit/nut industry. For vegetables, crop-specific marketing channels did not deviate much from the overall marketing pattern reported in Figure C2 and disaggregated information is not presented here. Post harvest handling is a crucially important component in marketing fresh-use crops. Thus, large commercial growers sometimes integrate field production with post harvest packing and shipping activities under the same owner. These growers are often referred to as grower/shippers . Table C2 indicates that 9 percent of the fresh-use growers who responded to the survey were grower/shippers. The vegetable industry had the largest proportion of grower/ shippers ; next was the ornamental industry , followed by fruit/nut operations . There is no parallel notion of post harvest handling for ornamentals and, thus, the remainder of the grower/ shipper discussion mostly relates only to fruits/nuts and vegetables. Grower/shippers operate on large scales and usually supply large-scale buyers such as grocery chains and mass-merchandisers , often at a pre-negotiated price. Negotiating the price before market conditions are known has important implications for price risk. Even though the net effect of prefixing the price depends on the structure of market power, a contract with a fixed price tends to reduce price risk. Our survey indicated that 51 of 75 fruit/nut grower/shippers sold, on average, 85 percent of their products at a predetermined price. However, for vegetables, the data indicated that only one grower/shipper sold product at a predetermined price.While grower/shippers typically supply their crops directly to large retailers or wholesalers, the grower-only group tends to market its crops through contracts with shippers or other means. As shown in Table C3, the two major outlets for fruits/nuts are marketing cooperatives and independent shipper/brokers. On the other hand, for vegetables, cooperatives have a minor role, and major roles are played by three marketing channels: direct marketing to consumers , independent shipper/brokers, and direct marketing to commercial buyers. Comparing marketing channels between processed and fresh-use crops, two observations stand out. With no single dominant marketing channel, fresh-use crops are generally marketed through various channels. Nevertheless, for fruits/nuts, the importance of cooperatives is significant—cooperatives are widely used in marketing both fresh and processed fruits/nuts.Production risk is closely linked to yield risk . As a way to measure yield risk, fluctuations in yields were investigated. The survey asked for information on actual annual yields from 1997 to 2001, and complete five-year yield data were obtained from about 45 percent of the respondents . Using the five-year yield data, average yield deviations in percentage were calculated and are reported in Table D1. To arrive at average yield deviations, for each observation we first calculated the simple average using the five-year yields. The percentage deviation from the average yield was then computed for each year . The all-year average deviation was the average of the five-year yield deviations. Table D1 presents the sample mean of all-year deviations by crop category and by crop-specific group. 

If the Q1 and Q3 are quite tight, then the quantification results are quite reliable. If the reciprocal labeling gives similar results, such as SR45, then the quantification should be reliable, even if the total peptides from this protein are only a few. We recommend at least three to four biological experiments be done for quantification, including at least one reciprocal labeling experiment . After the quantification is done, the users can evaluate the quality of the quantification of each protein and peptide of interest. Protein Prospector provides interactive feedback during the quantification process to allow for manual validation of the quantification results or visual assessment of what went wrong in case the ratio is incorrect. For protein quantification, a tight range between Q1 and Q3 often indicates the quantification is reliable. In cases where the range is big and the protein itself is of interest, then users can use the Cosine Similarity score to determine the quality of the matches or manually check them.Once the peptide sequence is identified, the elemental composition of the peptide is generated based on the peptide sequence. The CS score, similar to the Isotope Dot Product “idotp” product used in Skyline , automatically measures the similarity between the experimentally measured isotope pattern and the calculated pattern using the M, M+1, M+2 peaks, thus reducing manual checking time by auto-flagging the contaminated peaks .

The CS score ranges between 1.0 and 0.0 and can be determined by measured peak intensity or area. Figure 6A shows the pair have both good CS scores and the L/H ratio of this peptide is close to the median number of the protein. Figure 6B shows one peptide in the pair of another peptide from the same protein gives a lower CS score ,grow bucket and thus the L/H ratio of this peptide will produce an outlier ratio. Importantly, Protein Prospector takes account of labeling efficiency when calculating the CS score, as low labeling efficiency changes the isotope pattern quite dramatically. It should be noted that the CS score will be less accurate when the peak intensity of the peptide is very low. Users can create a cache file when submitting the quantification in Search Compare. This stores the data required to regenerate the Search Compare report in a JSON file. The cache function is quite useful for various reasons: when the user needs to retrieve the data or manually check the data, there is no need to re-calculate the quantification, which can take many hours for a large dataset. With the cache file, the reports come up quickly for a few seconds rather than hours; Often it is hard to display an HTML peptide report when many proteins or peptides are quantified. The cache function can allow visualization of such reports easily. This workflow allows users to report quantification of thousands of proteins and is applicable to the quantification of the total proteomes, sub-proteomes, and immuno precipitated samples . During the extraction of elution profile of every peptide identified, Protein Prospector averages together scans over a time window but doesn’t fit the peak shape to a Gaussian function. Therefore, each identified peptide/protein will be quantified and none gets discarded due to failing the scoring threshold for fitting the Gaussian function. To get high quality data, we recommend to get 97% or above labeling efficiency to achieve higher ID rates in 15N samples, so more proteins will be reproducibly identified and quantified between different replicates. Data acquired on high resolution and high accuracy instruments will also improve the quality of the dataset. A systematic normalization is normally required before comparing results between different experiments , as the samples are rarely mixed at exactly 1:1.

One choice is to use the median number of all the quantified proteins, or median number of top one hundred abundant proteins . Alternatively, users can use housekeeping proteins that are assumed to not change for normalization. Statistical analysis of quantification data on three or more replicates is advised. Users need to determine how to apply statistical analysis on the data using a separate tool. Benjamini-Hochberg multiple hypothesis test has been used to determine significant regulated PTM peptide groups in 15N metabolic labeled samples . A standardized statistic pipeline for protein quantification is still lacking, particularly a pipeline that can leverage quantification ratios of each peptide from a protein. Our current workflow uses a median value, which takes advantage of the quantification ratios of each peptide but is less affected by outliers than using the mean. However, the statistical power utilizing quantifications from these multiple peptides from single protein has not been explored and awaits development in the future. A targeted quantification strategy is recommended for further analysis of proteins of interest because this provides more accurate quantification and is less likely to have missing values, particularly in the 15N labeled samples . In addition to targeted analysis, data-independent acquisition can also be utilized, which can be done in label free samples or combined with 15N metabolic labeling in the future. DIA benefits from having few missing values, but more efforts will be needed to deconvolve the mixed MS2 spectra in DIA datasets. 15N metabolic labeling has been utilized in studies of analyzing protein synthesis and degradation . These studies are based on incomplete and often low incorporation rates which result in very broad satellite peak distributions and cause 15N labeled peptide isotope clusters to overlap with 14N labeled peptide clusters. As Protein Prospector doesn’t deconvolve the 15N distribution from the 14N distributions , the presented workflow will not provide accurate quantification in this type of study. On the other hand, for chase studies that analyze the assembly kinetics in vitro , the presented workflow can be applied because the proteins involved have a very high labeling efficiency.

This workflow can be also applied to the quantification of post-translational modification with a slight modification. The users will include related PTM search parameters into data search. Instead of reporting median number at protein level, ratios from each peptide are reported and then compared across different replicates. Trait analysis, especially genome-wide trait analysis, is centered on how genetic variation gives rise to phenotypic variation. This type of analysis relies on statistical methods and tools to perform association mapping between causal genetic variants and resulting phenotypes, which can determine the heritability of a trait at a subset of genetic variants and delineate regions of the genome that control the trait, thereby providing markers that can be utilized to accelerate breeding by marker-assisted selection. Because of the great success of genome-wide association studies , hundreds of SNPs conferring genetic variation of complex traits have been identified and reported. However, the genetic structures of most traits remain unexplained, as associated SNPs detected from GWAS explain only a small fraction of heritability and a much smaller percentage of the total phenotypic variance. This is mainly because a number of these studies employed only additive models that fail to account for epistasis,blueberries container or the interaction between multiple loci and the environment. Xu et al. proposed a new linear mixed model for mapping quantitative loci by incorporating multiple polygenic covariance structures. Based on this model, a pipeline for estimating epistatic effects was developed to com prehensively estimate additive effects, dominance effects, and interaction effects between multiple genetic loci. PEPIS allows analysis of genome-wide genetic architectures, including genotype interaction effects , and can thereby explain more than 80% of phenotypic variance. Compared with standard GWAS tools that consider only additive effects, the PEPIS pipeline is equipped with a more complex polygenic linear model that can explain more phenotypic variance. However, neither of these methods can explain nearly 100% of phenotypic variance, as neither considers the interaction between genotypes and environments . Today, the predominant thinking in biology is that the orchestrated expression of many genes in different environmental conditions affects the transcriptome, proteome, and metabolome to produce a final observable phenotype. Recent work in Saccharomyces cerevisiae suggests that GxE can occur at the individual locus level and the group level for multiple loci, leading to environment dependent epistatic interactions. Although Muir et al.conceptualized the partitioning of GxE into two possible inter action types, our mathematical understanding of the genetic and molecular mechanisms by which GxE collectively gives rise to phenotypes is still incomplete. The central dogma of biology is that the genome, tran scriptome, proteome, and metabolome are cascading and connected to the end phenome. The development of life science technologies enables transcriptomic, proteomic, and metabolomic events to be analyzed in detail within the same biological system, allowing the systematic study of a complete biological system.

Out of all the omic data from the same biological system, genomic data generally remain constant across environments, although the same genotype subjected to different environments can produce a wide range of phenotypes by triggering the expressions of different genes, downstream enzymes, and metabolites. Most current association methods and analysis tools perform associa tion mapping based on fundamental relationships between DNA sequence variation and phenotypic variation without addressing environmental variation. GxE can be understood by observing and measuring the expression of genes or metabolites. Harper et al.developed an associative transcriptomic approach to study complex traits in the polyploidy crop species Brassica napus by correlating trait variation with the quantitative expression of genes and sequence variation of transcripts, with the consistent physical positions of the two kinds of associative markers allowing the identification of high-confidence transcription factor candidates. However, their method is based on a pure additive model only, and they make no mention of interaction effects between biomarkers or their contribution to phenotypic variation. To overcome the limitation of standard GWAS that fails to consider the GxG and GxE effects, we extend associative geno mics and transcriptomics into a broader associative omics by systematically integrating all available omic data into one analytical model. Here we propose a new LMM and describe the development of a pipeline for analyzing traits through ome-wide association studies to implement the model. The proposed LMM considers not only the additive effects of each biological marker but also the interaction effect of each marker pair. The marker pairs’ interaction effect introduced here corresponds to two-dimensional association mapping, which is complementary to one-dimensional association mapping in regular GWAS. Consequently, the proposed model and PATO WAS pipeline are not limited to GWAS for genotype-to phenotype mapping ; instead, they are capable of per forming multiple types of ome-wide association studies, such as transcriptome-wide association studies for transcript-to phenotype mapping and metabolome-wide association studies for metabolite-to-phenotype mapping . We submit a rice recombinant inbred line dataset with three omics markers and two agronomic traits to PATOWAS for comprehensive analyses of associative omics. The results demonstrate that our proposed LMM and the pipeline PATO WAS can effectively address the GxG effect and the GxE effect, perform multiple-level associative omics in one platform, and innovatively provide a systems biology view into the traits analyzed.We aimed to systematically integrate multiple associative omic results to provide more biological insights into the phenotypic traits to be analyzed. We first collected a dataset of 210 rice RILs geno typed with 1619 marker bins, profiled with 22,584 transcripts and 1000 metabolites, and phenotyped with two agronomic traits . The phenotypic traits were yield and thousand grain weight , and the omic quantitative markers were bin based genotype data, Affymetrix RNA microarray-based gene expression data, and mass spectrometry-based profiling of metabolite abundance data. We presumed that expressed tran scripts, proteins, and metabolites are prone to vary when sub jected to the environments, while the genetic variants are considerably stable. Therefore, compared with genome-wide genotypic data, we further presumed that measured gene expression and metabolite abundance contain both gene and environment information and expect that associative transcriptomics or metabolomics could explain more phenotypic variance . Motivated by our consideration of genetic epistasis and our desire to explain more phenotypic variance, we next proposed astatistical LMM that considers not only the additive effects of the two components, the lower the residual component and the each marker variant but also the interaction effects of each more phenotypic variance can be explained by the model.

Crucially, fast initial fern growth in the medium-textured soil, likely due to higher nutrient content and/or lower arsenic phytoavailability, led to a decrease in effluent flow and therefore arsenic leaching, as transpiration exceeded water application. In this soil, the fern required less energy to acquire nutrients, released less arsenic from soil via nutrient scavenging, and produced greater biomass such that arsenic concentrations in biomass were lower. The increase in mass of arsenic accumulated from 11 to 21 weeks, coupled with lower final biomass of mature and young compared to senescent fronds, shows that arsenic accumulation continued even as growth slowed. This arsenic accumulation could be due to increased nutrient scavenging associated with drought stress.The increase in arsenic concentrations in leachate in the presence of ferns growing in the medium-textured soil reveals the importance of rhizosphere processes to arsenic release for uptake and leaching. We found that arsenic depletion from the medium-textured soil was the greatest in surface soil where P. vittata roots are primarily located . Moreover, in both soils we calculated that arsenic concentrations in rhizosphere pore water must be greater than those in bulk soil pore water,square planter pot because assuming arsenic concentrations to be the same in rhizosphere and bulk pore water indicated a discrepancy between arsenic intake through transpiration flux, and fern arse nic content. Processes other than mass flow of soluble arsenic from bulk soil to roots must be important for arsenic uptake .

If nutrients availability in soil is lower than P. vittata demand, P. vittata could employ nutrient-scavenging processes that release iron, phosphorus, and therefore arsenic from soil into pore water in the rhizosphere , increasing pore water arsenic concentrations locally to potentially very high concentrations. We suggest that the majority of the arsenic taken up into P. vittata was mobilized directly in the rhizosphere, similarly to others who found greater desorption of cadmium in cadmium hyper accumulator rhizospheric compared to bulk soils . We hypothesize that higher diffusivity due to greater connected pore space in the medium-textured soil could lead to transport of the arsenic re leased in the rhizosphere to the bulk soil, where it is then available for leaching. Similarly, rhizosphere DOC could be transported to the bulk soil and promote release of arsenic. However, in the coarse-textured soil characterized by lower porosity, larger pores, lower saturated fraction, and pre dominantly advective flow, arsenic and DOC released in the rhizosphere did not contribute to bulk leachate arsenic concentrations and, conversely, arsenic in the bulk pore water was not as accessible to the plants.We suggest rhizosphere arsenic mobilization is a byproduct of nutrient scavenging processes, particularly iron-scavenging in the medium-textured soil, where we found higher iron concentrations in ferns and in root zone pore water. Specifically, arsenic release from soil could be coupled to phosphorus and iron release from soil iron oxide minerals . Release processes could include ion exchange, ligand-enhanced dissolution, and reductive dissolution , likely tied to release of root exudates from P. vittata roots . We found primarily oxidized arsenic in our well-drained rhizosphere soil, suggesting processes including ion exchange and ligand-enhanced dissolution, likely coupled to rhizosphere DOC, are more important than reductive dissolution, similarly to in the Pine rhizosphere . Alternately, the predominance of oxidized species could indicate P. vittata preferentially took up reduced species, leaving oxidized species behind. We found evidence of reductive processes in the rhizosphere, with up to 41% of the arsenic present as arsenic in rhizosphere soil, up to 100% of the arsenic present as arsenic on and within roots, and iron phases in rhizosphere soil, suggesting reduced arsenic and iron could play a secondary role in arsenic release and uptake.

A high fraction of surficial arsenic could indicate transport of arsenic toward the root and accumulation in the rhizoplane, with slower uptake of arsenic enriching arsenic relative to arsenic on the root surface. The presence of arsenic on the root surface could also indicate efflux of arsenic from roots, which has been proposed to be a secondary tolerance mechanism in P. vittata and other plants under arsenic stress . In bulk pore water, bulk soils, and soil aggregates, the predominance of arsenic indicates arsenic can leach under oxic conditions. Arsenic availability for leaching, whether due to soil characteristics or influence of plant growth, is not dependent on reducing conditions. Indeed, arsenic mobility in soil increases at the circumneutral to alkaline pore water pH we observed . Arsenic mobilized as arsenic could be oxidized, perhaps coupled to reduction of the moderately-available soil manganese. Leaching of root derived dissolved organic carbon could also increase arsenic release from bulk soil for leaching.Rhizosphere nutrient acquisition processes have a specific significance in the case of hyper accumulators. Infertile soils could characterize the hyper accumulator ecological niche , such that P. vittata employs scavenging techniques and associates with indigenous AMF to acquire necessary phosphorus and other nutrients. We found Glomus spp. including F. mosseae were present across all treatments whether due to colonization by indigenous mycorrhiza or due to inoculation. In the very low nutrient coarse-textured soil, we hypothesize that extensive use of these scavenging processes cost metabolic energy, locally in creased already high arsenic availability, led to high uptake of arsenic and consequently even more energy expenditure to sequester this arsenic, and ultimately resulted in low biomass containing arsenic at high concentrations. The lack of effect of supplemental phosphorus in the coarse textured soil suggests it is a balance of phosphorus and other nutrients which are required to meet P. vittata nutritional needs. In contrast, in the medium-textured soil, we hypothesize the ferns used less energy to acquire nutrients.

Iron scavenging here was successful, apparently meeting fern nutrient needs and therefore limiting “byproduct” arse nicreleased from soil. Hence, P. vittata growing in the medium-textured soil experienced lower metabolic costs and consequently higher biomass until drought stress limited biomass production. In keeping with evolution under phosphorus starvation conditions , our results suggest P. vittata is less tolerant to extractable phosphorus concentrations greater than that of the medium-textured soil . Fronds of P. vittata growing in its native habitat in China were only 0.08% phosphorus, and ferns including P. vittata had the lowest phosphorus content of any flora group in China . We found phosphorus application delayed fern growth in both medium- and coarse-textured soils,hydroponic nft channel as has been shown for tropical forest ferns , leading to smaller senescent fronds containing lower amounts of arsenic.Our findings suggest that P. vittata is a good choice for remediation at the mesoscale, because arsenic uptake in ferns exceeded cumulative loss by leaching by an order of magnitude, and transpiration limited leaching compared to the absence of ferns. Decreased effluent volumes and cumulative arsenic leaching in both soils in the presence of ferns confirms the critical role transpiration plays in limiting water percolation and leaching of soluble, plant available constituents . The leaching to uptake ratio measured in this mesocosm system is not directly scalable to field conditions. We demonstrate that arsenic leaching during phytoextraction depends on soil characteristics, fern growth, and water input/evapotranspiration ratios, and therefore must be measured at the field scale. The constant water application required in our column study design could have increased leaching of arsenic relative to field applications. On the other hand, our experimental design could have limited plant growth and therefore nutrient scavenging activities, which we showed can increase arsenic release from soil. Larger biomass under field conditions could increase the influence of the nutrient scavenging geo chemical processes observed here and lead to increases in arsenic mobilization for both uptake and potential leaching, explaining the excess loss of arsenic from soil observed under field conditions . Counter intuitively, because we showed that P. vittata continued to phytoextract arsenic under drought conditions from the medium-textured soil to effectively limit arsenic leaching, phytoextraction could be best suited for dry soils with lower arsenic availability. Here, even though frond arsenic concentrations were an order of magnitude greater in coarse-textured soil ferns, mass of accumulated arsenic in coarse-textured soil ferns was only 1.2 to 2.4 times that of medium-textured soil ferns, while leached arsenic was also greater in coarse-textured soil, due to the lower biomass and lower transpiration. Alternatively, phytostabilization with species with high transpiration rates but lower iron demand could limit biotic and abiotic arsenic leaching.Such substrates typically have an inorganic and organic component . The organic component provides high porosity, low bulk density, and nutrient retention , which makes Sphagnum peat moss a strongly suitable option with widespread use .

However, increasing expense and competing uses for peat , impacts of its harvest on wetland ecosystems , including loss of peat bogs as a key global C sink , and its perception as unsustainable have spurred recent investigations of substitutes for peat in soil-free substrates, including biomass waste products such as compost and sawdust . Biochar has been recently proposed as a strong candidate to substitute for peat because of its high porosity, low density and high cation-exchange capacity. Biochar is a carbon -rich material produced by pyrolysis of biomass and has been a major subject of study as a soil amendment in the last decade . In addition to providing high nutrient and water retention, replacing peat with BC could offset or reverse the C footprint of soil-free substrates into a net C sink . Evidence to-date suggests neutral or positive effects of BC use in substrates on nutrient availability and plant growth , though many studies examine additions of BC to peat-based substrates, rather than replacing a substrate component such as peat .Evaluating effects of high BC substitution rates on substrate properties and plant growth is necessary to understand the extent to which BC can replace peat. At low amendment or substitution rates, BC has been found to maintain or improve plant growth as a result of increased nutrient availability , reduced nutrient and water loss , and amelioration of peat acidity , though these effects may be BC-specific due to feed stock and pyrolysis influences on BC properties . However, at high substitution rates, substrate properties conducive to plant growth may be compromised. In particular, the high pH of many BCs could result in BC-substituted substrates with pH values unfavorable to plant growth. For example, pelleted wood BC substitution for peat required adjustment of pH due to the liming effect of the BC . The neutral to alkaline pH of BCs and their liming potential means that BC substitution for peat can increase pH beyond optimum for plant growth in potting media . Explicit eva luation of BC effects on substrate pH and plant performance provides a basis to improve design of BC-based substrates and inform trade-offs in this application of BC . The objective of this study was to determine the effects of BC substitution for peat and substrate pH on greenhouse production, using marigold as a model crop. In the United States, the wholesale value of marigolds plants was 30.3 million USD in 2015 . Softwood BC was substituted for peat in a typical 70:30 peat:perlite mixture at 10%v increments. Since many BCs are alkaline and will increase pH of substrates in proportion to the degree of substitution, the effect of adjusting pH of substrates to typical soil free substrate values was also evaluated. Marigold germination and growth were measured over 9 weeks. We hypothesized that under greenhouse conditions , marigold germination and growth would be more sensitive to BC substitution at higher rates and that this would be due to elevated substrate pH. Additionally, we hypothesized that pH adjustment of BC substrates would increase the extent to which this softwood BC could be substituted for peat without compromising plant growth.Marigold var. ‘Crackerjack’ seeds were sown directly in 0.7 L of substrate pre-fertigated to 100% WHC using 0.5% Hoagland solution in 1.2 L polypropylene pots in a greenhouse at the UC Davis Plant Growth Facility. Pots were arranged 18 cm apart in a completely randomized block design with four replicates per substrate-pH treatment . Pots were drip fertigated with 0.5% Hoagland solution at 66 mL d−1 for weeks 1–6 and 99 mL d−1 for weeks 7–9.

For many important horticultural crops, ex ports constitute a large share of output, so FTO under IP must include freedom in foreign markets. Since the various IP rights important for plants are administered nationally, an exporter must check FTO separately in each foreign market. In general, the tools of biotechnology are more likely to be patented in just the major markets — such as the United States, Europe and Japan — and less likely to be patented in countries with smaller markets. Uses of bio-technologies specifically for minor crops are less likely to be widely patented in multiple countries than are uses in important field crops. However, as a result of the International Union for the Protection of New Varieties of Plants agreement first established in 1961, PVP systems are widely available overseas for the protection of clonally propagated varieties, and such varieties do tend to be widely registered in multiple countries. Still, not all types of bio technologies, genes or plant germplasm can be protected in all countries. For example, utility patenting of plants is allowed in only a few countries . Beyond these trends, however, there are no hard-and-fast rules as to which technology will be protected in which country, as each inventor decides where to seek protection . As a result, those seeking FTO are confronted by an often bewildering international patchwork of IP rights, where the negotiations needed for a particular transgenic variety can differ significantly each time it crosses a national border.Unless a new transgenic variety is developed by an integrated effort at a large company backed by a broad IP portfolio, a number of different owners — including companies, individuals,ebb and flow trays universities and even governments — will have valid IP claims over the technologies and genetic contents that end up being included in it.

That means there are numerous owners to track down, negotiations to conduct, billable legal time to hire, and multiple royalty payments to administer. The costs and headaches involved in working out “who owns what” and “who owes what to whom” can balloon into what economists call the “tragedy of the anti commons” and render the development process unfeasible.Given the smaller markets involved, there is less incentive in industry to consolidate IP portfolios around horticultural crops. Also, not one of the public-sector organizations or their typically smaller commercial partners in horticultural crop development has a complete IP portfolio in plant biotechnology.When technologies are patented, it is often not clear who currently owns particular aspects of each technology. This uncertainty is cleared up in the courts through patent interference cases, where attorneys and scientists under take intensive “surveying” of the “property lines” between the patents and technologies in question. Some times these cases drag on for years, keeping key technologies in legal limbo and the R&D community guessing as to who is the rightful owner. Yet, for most registered patents there is no such scrutiny. As a result, the boundaries for a considerable expanse of technological territory are not clearly demarcated, creating considerable uncertainty as to when a new application could be considered to be infringing or “trespassing.” In horticultural crops, the lack of clarity about the scope and validity of patent claims is especially important. Because the markets are smaller, fewer products have been developed and fewer contests have been fought to establish legal precedents. Furthermore, just the anticipation of possible legal costs can shut a project down before it ever gets off the ground.IP covering a crop variety may be sold, licensed or transferred to another organization at any time. The transfer of rights can occur either in part or in whole .

The transfer can happen in just one territory where it is protected or in multiple territories. The transfer of rights for a biotechnology tool or gene could be specified for use in just one crop , in several crops , or in any and all crops. Finally, to make matters worse, the fact that the IP rights have been transferred may be considered commercially sensitive information and not be made public.Any organization managing the release of a new crop variety faces uncertainty about which IP rights actually cover what technologies, who holds those rights in which countries, and to what degree a specific new transgenic variety infringes on those rights. Resolution of such uncertainty is not less costly for crops with smaller market values. Even after reliable information is obtained, uncertainty remains about negotiating the permissions. IP owners are not required to negotiate licenses, and they may feel there is not enough potential revenue in minor crops to make their licensing efforts worthwhile. They may also be concerned about technology stewardship, given the nervousness among consumers about food biotechnology and its status as a hot media topic. They may worry that the mishandling of their technology by a small and relatively inexperienced horticultural player could lead to stronger regulations, potentially eroding that technology’s value in its major crops, or jeopardize public perceptions about biotechnology overall.In response to IP congestion and continuing uncertainties, several leading U.S. public-sector agricultural re search organizations have come together to create the Public Intellectual Property Resource for Agriculture , an organization providing col laborative IP management solutions to public-sector and smaller private-sector players in horticulture . While individual universities and even the USDA have small and uncoordinated IP port folios in plant genetics, together they hold a fairly comprehensive set of technologies that could be useful for developing transgenic varieties .

PIPRA seeks to coordinate the disparate portfolios of its member organizations to support specialty crop applications. With the offices of technology transfer of its member organizations, PIPRA is pursuing several cooperative strategies.First, PIPRA seeks to develop and adopt more precisely focused terms of licensing, with specific distinctions for the “fields of use” to which a technology is licensed. A company that licenses a technology in vented at a university can still get the full benefit of using the technology in those major row crops in their line of business,grow strawberries container even if the license clearly defines and grants exclusive use of the technology in just those crops. Such a license effectively “reserves” the rights to use the technology in any other crops. Horticultural firms could then make separate agreements with the university to use the technology in only their defined specialty crops. An ad vantage of this strategy is that it can also apply to other minor uses, including “alternative” crops and humanitarian applications in staple crops for developing countries . By discriminating be tween big markets and multiple smaller markets — including those with limited commercial value but important social benefits — public-sector scientists could see their inventions earn royalties in the big markets of ma jor row crops while still helping to improve smaller crops or increase food security in world’s poorest regions.A database will, for the first time, list in one place current information about all of the patents of PIPRA’s members and their availability for licensing alongside information about technologies published in the scientific literature , in sufficient detail to identify which technologies can be accessed for which uses. The database will offer a clear, complete and certain “universal listing” of technologies available from PIPRA’s member organizations and the public domain. Commercial patent databases and professional legal staff are available to researchers in large private companies for searching through the “prior art” to make FTO analyses of a new product’s IP position. Such resources are seldom available to academic and government researchers.

The PIPRA database will decrease uncertainty about what cannot be used by showing what can be used.PIPRA is investigating the creation of patent-pooling mechanisms, which would collect IP submitted from its member organizations, package the technologies together and offer unified licenses for the “bundled” IP in a field of use, such as a specific crop, or in a particular state or country. This process mimics, in a virtual way, how large commercial firms have assembled their IP portfolios to provide FTO in major field crops. Its feasibility will depend — at least at the outset — on the extent to which public sector organizations are able and willing to provide access to patents covering key enabling biotechnology tools already licensed to the corporate sector. Even if used to access technologies on just a patent-by-patent basis, coordinated information and streamlined access to academic and government owned IP could help decrease trans action costs and improve efficiency in technology-transfer markets. There is ample room for improvement here, as some have complained that negotiating licenses from universities and government agencies is often less efficient than negotiating licenses from firms. PIPRA can improve public-sector technology transfer for agriculture by providing information, tools and precedents for efficient licensing. Greater opportunities lie in the The costs and headaches involved in working out “who owns what” and “who owes what to whom” can balloon into what economists call the “tragedy of the anti-commons” and render the development process unfeasible. steps being taken to coordinate access, package IP bundles and target uses in lower-value markets such as horticultural crops and traits important for food security in developing countries. These are, generally speaking, areas that commercial firms are not interested or capable of serving. Such collaboration is not surprising, given the history and ethos of cooperation among agricultural experiment stations within the land-grant system. Public-sector institutions also have greater legal flexibility to enter into collective IP management arrangements, given historical antitrust concerns about abuses of patent-coordination efforts in industry. Even more important will be the establishment of ongoing precedents and mechanisms for the treatment of future IP. Academic and government re searchers will go on making important discoveries and inventing new technologies for agriculture. Those future inventions will, from their inception, be handled in ways — such as being listed in the universal database, licensed for targeted “fields of use” and included in IP pools — that will make them accessible in a carefully proscribed manner, not just to top commercial bidders, but to anyone else in the broader agricultural community who can make good use of the technology, including horticultural researchers and growers.Current practices in patenting and intellectual property protection have created barriers to the use of biotechnology and advanced agricultural technologies for the creation and commercialization of new crop varieties. The complex and cumulative nature of biological innovation requires access to multiple technologies that are often exclusively owned or licensed. For example, commercializing a single variety of transgenic tomato could involve obtaining the rights to use a variety of technologies and genes from numerous life-sciences companies, government agencies and universities. Obtaining “freedom to operate” for transgenic crop varieties is difficult. There is considerable uncertainty as to who holds what rights to particular technologies, and negotiating access to those rights is time-consuming and costly. This is a problem for the major international agricultural companies that focus primarily on high-volume crops such as corn, soybeans and cot ton; for research institutions that work on specialty crops grown on much smaller acreages, such as tomatoes, strawberries, apples and cabbage; and for public institutions that work on staple crops for humanitarian use in developing countries. The international agricultural companies have taken steps to solve their FTO problems through mergers and cross-licensing agreements that bring together essential IP components within one company. However, public-sector institutions — such as universities, government agencies, international agricultural research centers and others working on specialty and staple crops — are still struggling to find ways to gain FTO. In addition, donor agencies such as the Rockefeller and McKnight Foundations, which have a long history of investing in agricultural research that benefits subsistence farmers in developing countries, have also found that IP constraints are reducing the flow of technology.Universities and other nonprofit institutions have generated many key patents related to agricultural bio technology and they will most likely remain an important source of innovation. However, no single institution has the complete package of technologies required for commercialization of a biotech variety. Although some institutions are developing ways to deal with these problems, there are still many examples of public-sector inventions that have been licensed exclusively to private-sector partners. In late 2002, representatives of more than a dozen U.S. public-sector agricultural re search institutions joined with the U.S. Department of Agriculture and the Rockefeller and McKnight Foundations to discuss access to patented agricultural technologies for the development and distribution of improved specialty crops and those targeted for the developing world.

A stainless steel hand auger with a Teflon® coated-core sampler was used to collect the soil samples. To minimize cross contamination, a polyethylene core liner was utilized. Soil samples were obtained from the topsoil and composited. The forage soil samples were obtained by utilizing a topographic soil zone sampling pattern using a random zig-zag pattern. Soil samples were weighed at 100 g. Physicochemical properties such as temperature, pH, Munsell color, depth, and moisture were obtained. The sheep tissue samples were paired with the forage, soil, and water samples. The mean age of adult sheep harvesters was 58.67 ± 2.89 years; two of three participants were male. All sheep parts were consumed by the participants for a mean of 52.33 ± 10.78 years. The sheep harvesters reported that 35% of their overall meat intake came from sheep they raised and harvested locally. On average, all the participants reported consuming locally raised sheep once a week. The local harvesters reported other important non-food uses for sheep. All participants reported selling wool, and two reported using the locally harvested wool to create textiles to sell for income. One of three harvesters reported selling live sheep to market, and two reported selling sheep or lamb cuts to market. All the participants reported sharing sheep meat for free with others. On average, each sheep harvester distributed free meat to two households. Multiple sheep parts were reportedly used for various ceremonial or cultural purposes by all harvesters.The existing literature reports HM levels in kidney tissue,ebb flow table but typically there is no comparison between the kidney medulla and the renal cortex. In this study, the kidney medulla rather than the kidney cortex showed an increased uptake of U, Se, Mo, and As.

The renal proximal tubule epithelia arechemically damaged by high acute levels or prolonged low doses of U; the proximal tubules are housed in the renal cortex. The administration of toxic doses of Se demonstrated histopathological changes in the proximal tubules of the sheep. The kidneys maintain Se homeostasis. Renal compromise may cause dysregulation of Se. Our study indicates there may be a difference between HM accumulation in the medulla and the cortex. The renal toxic effects of U and Cd are well supported in the literature. The effects of associated heavy metals on the sheep kidney need further exploration. Meat protein is richer in Se than plants. The literature supports that Se commonly concentrates in the liver and kidneys of animals. Of all sheep organs, elevated Se levels were found in the liver and kidney medulla . In a lamb tissue study, it was reported that Se concentrations in the kidneys were seven to 44 times higher than in other tissue and organs. Similarly, in our study, the medullary levels contained the higher concentrations of Se . The above lamb study reported that leg muscle contained the lowest Se concentrations of the tissues sampled. We also found that leg muscle contained the lowest Se concentrations in our examination . There is a narrow margin between Se requirement and toxicity. Therefore, taking an accurate measure of food intake containing Se, particularly meat protein, is important. Food processing such as cooking via baking, boiling, and grilling may alter the amount of Se in food. Whether food processing has an additive or minimizing effect on Se concentrations in food is to be determined by research. Adjusting food intake and cooking habits based on various HM measurements and bio-availability may be a plausible intervention once it is informed by research. Elevated levels of Se and Pb were found in sheep wool in the current study. Further, though Th was negligible in all other sheep tissue, it was detected in sheep wool .

This finding may indicate that Th may be accumulating across time in sheep wool. Direct dirt and dust aerosol capture and the effects of lanolin may be contributing exposure factors. We did not measure the effects of lanolin in this study. The current study community relies on wool to create textiles. It is common practice to place local plants in hot water to pigment the wool. The wool is handled often by weavers once the wool is removed from the animal, hand-carding the wool, hand-spinning, dyeing, and weaving the textile. The entire process often takes weeks to months, suggesting a potential lengthy human exposure to heavy metals. A considerable amount of time is spent outdoors for such activities, and exposure to various sources of contaminants such as soil, water, and air is a concern. Although this study of three sheep provided interesting insight, future studies should focus on determining the speciation of heavy metals and evaluate which metals have a greater affinity to wool. The majority of the time for this study, heavy metals were found in the greatest amounts in soil > forage roots > above-ground forage parts, respectively. The current study mean Se soil concentrations were equivalent or exceeded the exposed soil and were greater than the control concentrations reported by Dreesen and Cokal. The above-ground forage parts contained the least amount of heavy metals, except for Mo and Cd. The bio-accumulation ratio can partially demonstrate the ability of particular plants to absorb soil heavy metals and transport them to the above ground portions of a plant. The data shows that the uptake of Cd, Mo, and Se by most plants sampled were high under current soil conditions. The highest BF ratios were seen in most forage for Mo , Cd , and Se , which needs further exploration. The high BF ratios seen may indicate a low tolerance of various plants to high concentrations of Mo and Cd. In particular, B. gracilis the most abundant plant, was associated with elevated BF ratios for Cd, Mo, and Se.

Generally, in the biota samples there were greater heavy metal concentrations in the plant roots than the above-ground portions, which is consistent with several other plant studies that found that U translocates in greater amounts to the roots than the shoots. Similar to the current study, Soudek et al. reported that U was more localized in the root system. Uranium accumulation was less in grasses than root crops and Brassica spp.. Uranium uptake was found to be 3.9 or 4.5higher in the presence of phosphate deficiency. The micro and macro-nutrients available in soil affected the uptake of Cd in one source. Geochemical characteristics have an important influence on HM plant uptake. Future investigations can focus on the interactions between trace elements or other factors that may demonstrate an influence on HM plant uptake. Forage and water intake are important considerations in livestock,air pruning pots and soil ingestion must also be considered. In the current examination, the soil samples showed greater HM concentration than sheep tissue and forage samples. It has been demonstrated that sheep, a ground feeding animal, eat one to two percent of soil when good forage is available and about 18% when low quality forage is available. It has been shown that sheep intake and digestibility of more mature plant material decreases with advancing maturity due to greater effort and time in chewing by the animal; sheep selectively graze in high-quality forage areas when they are available. The forage environment of the sheep in the current study area exhibited high stocking rates, sparse vegetation, and mature forage samples, which may have contributed to higher HM concentrations in forage. Dung analysis can evaluate the amount of inorganic material in sheep diets and may be useful in future studies in the current study area. Previous studies have reported the concentrations of HMs in sheep tissues, plants, and soil in the target study area . In most categories, our study results were comparable to or less than what was previously found.

The current study tissue measurements were below the exposure and control concentrations reported by Millard et al. and Ruttenber et al. in the 1980s. No excess cancer risk was calculated to be attributed to eating sheep meat, liver, kidney, and soup bone by humans; researchers recommended continued monitoring at that time. The highest HM metal concentration in the diet was used for each animal to calculate and compare to the maximum tolerable concentrations, and the lowest concentration for each HM was used to compare to the requirements for Mo and Se. The calculations are based only on the forage samples collected and are not representative of the complete sheep intake. Maximum tolerable concentrations are established for sheep intake for As Cd, Pb, Mo, and Se. All study animals did not exceed the calculated maximum tolerable concentrations for As, Cd, Mo, and Pb. All study sheep met the Mo and Se dietary requirements. Liver is the organ of choice to diagnose Se deficiency, and concentrations less than 0.21 mg/kg in sheep liver are considered deficient. All study sheepliver concentrations did not indicate deficiency. In sheep, Se toxicity was reported at 0.25 mg/kg of body weight chronically. However, the National Research Council set the maximum tolerable concentrations for Se at 5.0 mg/kg of DM. Of the donated sheep, the shepherds did not report indicators of acute or chronic Se poisoning . Other supplementary sources of forage were not reported at the time of sampling; sheep harvesters reported relying on alternative fodder sources for their sheep in the late winter months only . New Mexico is one state that was reported to have high Se concentrations in soils and those in areas with low annual rainfall or alkaline soil. The mean study soil pH was 7.31 ± 0.51. Primarily, most of the Se is absorbed in the small intestines of ruminants and less absorption is seen in forage based diets versus diets based on concentrate. Plants that accumulate Se may be unpalatable to grazing animals, but if there is lack of more palatable forage, animals may develop signs of toxicity from ingestion. According to one study calculation, selenosis can occur in lambs ingesting 0.2% BW of Se accumulating plants. Soil ingestion during foraging, seasonal soil forage adhesion , pulling up of roots while foraging, and licking snouts by livestock may also contribute to higher HM concentrations. The forage plants that we sampled were not known Se obligate or secondary accumulator plants. Aside from Se, whether study plants accumulate Mo and Cd needs further evaluation. Selenosis diagnosis is primarily based on Se measurements , anemia and the presence of physical examination findings identifying toxic levels.One source reported that plant forage containing >3–5 mg/kg induced toxicity in sheep. In our study, several plant roots exceeded 3 mg/kg, which is a concern with the pulling up of roots when sheep forage. The amount of root consumption in relation to the total sheep forage intake is important to determine. Further work examining these factors is an area of future research. Based on drinking water standards for livestock, none of the heavy metal concentrations were above maximum tolerable concentrations . Heavy metal water measurements collected by the DiNEH study from two of the water sources identified for Sheep 3 contained lower concentrations of Pb in comparison to our data ; the remaining HM data were less than what the DiNEH researchers found. Most of the shepherds obtained public water for sheep consumption, which was reflected in the concentration levels found in sheep water. Harvesters in the study reported a history of consuming unregulated water intended for livestock. However, the As, Cd, Pb, Se, and U concentrations did not exceed the maximum contaminant levels set for human consumption. The implementation of water use maps may have contributed to the use of safer alternative water sources for these shepherds. Continued emphasis on the use of safe alternatives for water use in sheep and human consumption put forth by deLemos et al. is essential. Harvested food selling and sharing was common among the participants in the study. Emphasis should be placed on determining the incidence and frequency of food selling and sharing when assessing food chain contamination. Harvesting locations and activities can overlap in mining impacted areas. A few important factors to consider include the availability of harvest items based on seasonal variation and peak consumption periods . It is important to consider the consumption of contaminated food not only by individuals and their families but potentially the whole community and beyond.

It could hardly be otherwise, given that it is such a highly profitable business. When coca paste leaves Peru, it is worth US$400 per kilo; it then reaches Colombia, where it is processed and becomes cocaine, valued at US$1,200 per kilo; in Miami, the same amount is sold for US$20,000, and is transported to Chicago, where it fetches US$30,000 wholesale and is sold to individuals for approximately US$140,000 per kilo. Figures for heroin are even more fabulous; its sale is four times more profitable. This being so, one might spray Colombia all over, from the Amazon to the Andes, with every kind of chemical or fungus available, and the effect would be precisely the same: the drug phenomenon will continue to thrive. Meanwhile, this phenomenon is rapidly becoming a tremendous catalyst for a kind of rebellion, one which is brewing amongst those who have traditionally been excluded from Colombia’s society. It may not constitute a genuine revolution, but could well explode in an amorphous, uncontrollable uprising by the dispossessed. Since its launch in 2009, Evergreen Co-operative Corporation, a network of worker-owned co-operatives in Cleveland Ohio, has magnetized media, political elite, and academic attention. Evergreen has garnered supportive coverage in the Economist, Harper’s, The Nation, The New York Times, Fast Company, Time, and Business Week. Sarah Raskin lauded the initiative in 2013 while she was serving on the Board of Governors for the Federal Reserve System .Ron Sims, then Deputy Secretary for the U.S. Department of Housing and Urban Development, referred to the Evergreen network as “brilliant” during a 2011 interview .

Intellectuals on the Left have also been attracted to the initiative: Noam Chomsky has celebrated Evergreen in interviews and public talks,ebb and flow bench and the initiative has been cited by numerous academics as a hopeful alternative to the capitalist firm and its social and environmental externalities . Evergreen is currently comprised of three worker-owned co-operative enterprises: Evergreen Laundry , Evergreen Energy Solutions , and Green City Growers . Evergreen was designed to capture procurement flows from area “anchor” institutions: large hospitals and universities that are unlikely to leave the community, have a general commitment to improving it, and can do so by leveraging their purchasing power in support of local economic development . While Evergreen currently employs approximately 120 people, the vision is that it will become a large network of worker co-operatives that can rejuvenate the depressed regional economy in Cuyahoga County and inspire replications in other regions across the United States. Evergreen’s key features are ensuring worker ownership, harnessing the local wealth of anchor institutions, and prioritizing sustainable service delivery.Supporters refer to Evergreen as the “Cleveland Model,” an approach that can be pursued in communities across the country . According to leaders with Evergreen, “What’s especially promising about the Cleveland model is that it could be applied in hard-hit industries and working-class communities around the nation” . Despite all of the attention, the Evergreen case has not yet been studied in a sustained way. Furthermore, there is a dearth of literature on co-operative development in general . With this article we aim to contribute to the collective learning that can happen from successful and failed co-op development experiments. Building this knowledge is especially important at a time when heightened contestation over neoliberal capitalism has intensified interest in the co-operative model . Our primary finding is that Evergreen’s development depended on contextual factors that might not be replicable: a supportive and wealthy community foundation and champions within local government.

The post-2008 period of contested neoliberalism in which Evergreen emerged created opportunities for new alliances, as diverse actors were willing to consider alternative economic models. These alliances were critical to Evergreen’s emergence, but similar connections might not be available elsewhere. The fact that Evergreen’s start-up relied so heavily on context-specific private and ad hoc arrangements suggests that moresystematic, government-supported programs of financing and technical support are needed if worker co-operatives are to thrive in North America. We conclude that bottom up, movement-driven action often precedes – and creates a climate for – policy change. Our analysis therefore falls within the social movement approach to co-operative development, which argues that robust popular movements are integral to successful development of co-operatives and often predicate policy breakthroughs . While Evergreen’s replicability may be limited, its social movement orientation and ambition to scale up the co-operative alternative to neoliberal capitalism position it as a contributor to the important project of movement building that can facilitate the policy change needed to grow the co-operative economy. To contextualize our case study we conducted an extensive literature review on co operative policy, focused specifically on co-op dense regions . Our research team then visited Cleveland in May 2013. We did site visits to Green City Growers and Evergreen Laundry, interviewing management and speaking with employees at each location. We also conducted semi-structured interviews with key actors involved in the conception and implementation of the project. We sought from the outset to make our findings relevant not only to academics, but also to practitioners in the co-operative movement.We thus undertook this project as a form of “movement-relevant” research . According to Bevington and Dixon, movement-relevant research “emerges out of a dynamic and reciprocal engagement with the movements themselves.

This engagement not only informs the scholarship but also provides … accountability” . Our research team would like to see Evergreen and the co-operative movement in general thrive, and this article is an effort to understand the conditions that might enable this success. We believe, following Bevington and Dixon, that this commitment to the co-operative movement does not lead to bias, but instead adds incentive to provide the “best possible information” to movement participants and supporters. Interest in the “Cleveland Model” has cut across the political spectrum, coming not only from progressive media and academics on the Left, but also from conservative venues like the Economist and the Federal Reserve Board. Evergreen emerged one yearafter the 2008 financial crisis, during heightened contestation over the philosophy and policy mix that has guided political economic affairs for the past forty years: neoliberalism. Neoliberalism involves a significant reduction in the state’s social and environmental welfare role coupled with an expansion in the state’s facilitation of private capital accumulation . While neoliberalism has been consistently challenged since it arose in the late 1970s,strawberry pots contestation became mainstream after 2008, as the financial crisis raised questions about the viability of under-regulated financial markets and the growing inequality that helped fuel increased consumer reliance on credit . During this period, too, climate change moved into the mainstream of political debate: in 2007 Al Gore’s film An Inconvenient Truth won an Academy Award, and Gore shared the Nobel Peace Prize with the Intergovernmental Panel on Climate Change. As Gore himself articulates, neoliberal philosophy and policy has been a significant impediment to strong government action on climate change . This more mainstream contestation of neoliberalism – fuelled by economic crisis, rising inequality, and climate change – has not facilitated the emergence of broadly accepted alternatives, leading some critics to worry about a “zombie neoliberalism” that will not die . While the post-2008 period of contestation has not enabled a consensus solution to neoliberal capitalism’s contradictions, it has powered the search for alternatives . Ideological perspective necessarily conditions the kinds of solutions different actors seek and support. American political elites like Sarah Raskin and Ron Sims, for example, are interested in innovative ways of addressing inequality and ecological strain that leave in place the fundamentals of capitalism . Radical critics like Chomsky are interested in systemic alternatives to not only neoliberalism but also capitalism itself . Co-operatives, Evergreen founders note, provide alternative economic models that “cut across ideological lines – especially at the local level, where practicality, not rhetoric, is what counts in distressed communities” . Evergreen, then, is an ideologically flexible initiative: an innovative market-based poverty alleviation strategy or the germ of capitalism’s successor, depending on one’s point of view. While Evergreen has benefitted from the surge of interest in economic alternatives post-2008, the whole co-operative movement is experiencing resurgence. The General Assembly of the United Nations declared 2012 the International Year of Co-operatives. The International Co-operative Alliance , an organization representing the global co-operative movement, recently reflected that “rarely has the argument in favor of co operatives looked stronger”.

Co-ops can be read as either an ethical supplement to neoliberal capitalism, one that evens out its contradictions in distressed communities, or they can be read as the basis for a systemic alternative. Leaders of the Cleveland Model explicitly subscribe to the latter, more radical view, even as they strategically benefit from the former. Evergreen is modeled after the Mondragon Cooperative Corporation in Spain, which has long been a model for large-scale co-operative development worldwide. Founded in 1956, MC is now a conglomerate including 110 worker co-operatives, and employing more than 80,000 workers . Mondragon does business in manufacturing, retail, finance, and knowledge . As a worker owned co-operative system, Mondragon has several features that distinguish it from traditional capitalist firms: for example, a pay cap specifies that top earners with MC can only earn six times the pay of those in the bottom bracket . By comparison, CEOs for US corporations regularly make 400 times an average worker’s salary – a rate that has increased twenty fold since 1965 . Mondragon is one of the largest employers in the Basque region of Spain where it is centered . The Mondragon model is not without its challenges, including the recent bankruptcy of Fagor, one of its larger companies , but it remains an example of how co-operatives can operate on a large scale, produce considerable wealth, share it equitably, and promote relative worker satisfaction. As such, Mondragon is a longstanding inspiration for movements and intellectuals interested in alternatives to the capitalist firm and economy . Replicating Mondragon’s successes, however, is no easy task. The region’s political culture is an enabling factor: Basque country is home to a robust nationalist and separatist movement, and considerable associational energy is generated from feelings of marginalization at the hands of a dominant majority .Political culture supportive of co-operative development is not easily replicated, a fact that limits the ability of the co-operative movement to transplant successes from one region to another . Evergreen has generated popular and movement excitement partly because it appears to have successfully adapted the Mondragon model for North America. Northeast Ohio is not home to a political culture distinctively supportive of co-operatives. As Ted Howard, one of Evergreen’s leaders, told us, “Some people think there must have been something about the Cleveland community that would welcome this co-operative development, but it was a foreign concept” . As we learned, however, key supports were available in Cleveland – mainly a wealthy community foundation and champions in local government – that might not exist in other North American communities.Cleveland is still struggling to recover from the economic decline that began in the late 1960s. Once the fifth-largest city in the US and a center for manufacturing, Cleveland was hit hard by forces of economic globalization and the deindustrialization they brought. Plant closures, unemployment, and out-migration contributed to a depressed urban economy. Between 1970 and 1980, the city lost 24 percent of its population, one of the steepest drops in US urban history . Those who left generally had the means to do so, “with the poor, elderly, structurally unemployed, or marginally unemployed remaining behind” . White flight, the large-scale migration of whites from racially mixed urban neighborhoods to more suburban regions, was also a factor in the hollowing out of Cleveland . In the 1990s Cleveland began to slowly recover economically, and the city is currently a hub for health care services, biotech, and polymer manufacturing . The two largest employers in the region are the Cleveland Clinic and University Hospitals, together employing 46,000 people . Both institutions are located in the Greater University Circle , an area four miles east of downtown that is also home to Case Western University, the Cleveland Museum of Art, and the Museum of Contemporary Art.

Wang et al. investigated the role of light quality, specifically, low red to far-red ratios , on photo protection during cold stress in tomato. They showed that L-R/FR activated two pathways associated with cyclic electron flow : the PGR5/PGRL1A- and NDH dependent complexes, respectively. These CEF complexes help to reduce cold-induced photo damage of the photosynthetic machinery by accelerating the thermal dissipation of excess energy, enhancing ROS scavenging, and reducing the hyper reduction of the electron transport chain. This work therefore provides a better understanding of the mechanistic relationship between varying light quality and low temperature in plant photosynthetic performance in temperate climates when seasonal variation induces these conditions. Spring frosts cause important economic losses in many fruit-producing areas of the world, and there is interest in identifying feasible approaches to mitigate these risks. Ethylene controls fruit ripening in climacteric species but it also plays an important role in plant stress responses . Published literature on the use of ethylene or ethylene-based compounds for protecting temperate fruit orchards against frost damage was reviewed . Experimental evidence of ethylene modulation of bud dormancy and blooming were presented and discussed. It was suggested that ethylene-delayed bloom and the associated frost protection may result from either the slowing down of floral bud responsiveness to seasonal temperature changes, an antagonistic interaction with other hormones such as abscisic acid or gibberellins, plant sensing of exogenous ethylene as a stress signal leading to longer dormancy, or ethylene-enhanced ROS accumulation resulting in extended bus dormancy.

Because chilling stress in plants often leads to ROS accumulation, the questions arises whether improving the antioxidant capacity of tissues by the exogenous application of antioxidant treatments may help improve tolerance to cold as well as to other types of abiotic stress. To this purpose, Tang et al. treated low bush blueberry seedlings with hydrogen sulfide,vertical farming racks and found that treated plantlets performed better under low temperatures than the untreated controls, as shown by the alleviation of membrane peroxidation, the reduction of chlorophyll and carotenoid degradation, and the lessening of photo system I and II photo inhibition. Conversely, the application of hypotaurine, a H2S scavenger, aggravated the oxidative symptoms under cold stress. Brassinolide is an important plant stress hormone shown to promote plant resistance to low-temperature environments. Zhang et al. investigated the effects of exogenous BR on the photosynthetic characteristics, leaf anatomical structure, and chloroplast ultra structure of two species of tung tree seedlings under different temperature conditions. The results suggested that long-term low temperatures significantly reduced the photosynthetic efficiency of tung tree seedlings, affecting the formation of the internal structure of plant leaves and destroying the integrity and function of the chloroplast. To prevent this, external application of BR to tung tree seedlings could enhance the photosynthetic potential of tung trees by maintaining the stability of the leaf structure and morphology and alleviating the damage caused by cold injury. In summary, the papers in this collection illustrated the breadth of research aimed at understanding chilling responses in horticultural crops, but more importantly provided new insights that will further our future basic and applied research in this area.

Agriculture has been an important engine of economic development, and the mainspring of economic progress in agriculture has been productivity improvements driven by technological change that is fueled by re search and development . Since World War II, agricultural productivity has more than doubled in the United States, as in many other countries. California agriculture today produces more than twice the output of 1950, using roughly the same total input — although with less labor and land, and more capital and purchased inputs. These gains can be attributed to new biological, mechanical and chemical technologies, including improved genetic material, machines, fertilizers and pesticides, and knowledge. The current wave of technological progress continues this pattern, while emphasizing information technologies and biotechnology — in particular genetically modified crops. For many, GM crops represent the hope for a future with less hunger and malnutrition, and for a more sustainable agriculture with more varied, cheaper and safer food. For others they are cause for serious concern about the environment and food safety. Regardless of how we may feel about it, the juggernaut of technological change continues and the biotechnology revolution is well under way in the United States and other countries. The challenge for public policy is to determine what regulations should be applied to govern the development and use of these technologies, and what other types of intervention may be necessary, such as public investments in research to correct for private-sector under investment. In the case of horticulture — the cultivation of fruits and vegetables, tree fruits and nuts, turf grass, flowers and ornamental crops — these is sues are sharply drawn because the private sector has not found it profitable to develop or commercialize many GM crops in the current political, legal and market environment.

What will happen in biotechnology applied to horticultural crops is up to the government, for a variety of economic reasons. Some of these aspects may be unique to GM horticultural crops but many are common to GM crops generally, and similar issues arise with some new non-GM technologies.Without government intervention, the rate of innovation will be too slow, reflecting both under investment in research and under adoption of some research results. Both problems are related to the nature of property rights for re search results. “Free-rider problems” occur when property rights are incomplete, and privateinves tors can capture only part of the re turns to their investments in certain types of research ; as a result, their incentives to invest are reduced. On the other hand, when the rights to research results are protected, such as by patents or trade secrets, the owner of a new variety can charge monopoly prices,maceta cuadrada 25 x 25 unduly limiting the use of that variety. Intellectual property rights are a double-edged sword: to the extent that they pro vide a greater incentive for investing in research they are also likely to result in lower adoption rates. Governments have addressed the incentive problems in agricultural research in several ways. Federal and state governments have funded agricultural research at public institutions such as the U.S. Department of Agriculture and state agricultural experiment stations associated with land-grant colleges. This approach allows an increase in total research with out the problems associated with monopoly pricing of inventions. How ever, even though the investment has paid handsome dividends, it is increasingly difficult to sustain the past levels of funding for public agricultural R&D, in the face of general budget problems and declining political sup port for public science funding, including agricultural science . Governments have also acted to strengthen IPRs applied to plants and animals as well as mechanical technologies; and changes in IPRs, especially in the 1980s, were crucial for the agricultural bio-technol ogy development that followed. Partly as a reflection of enhanced IPRs, in the United States, private-sector funding of agricultural research has been growing faster than public-sector funding and now exceeds it. The balance in agricultural R&D be tween the private and public sectors varies among types of research. For in stance, until recently the private sector emphasized agricultural R&D pertaining to mechanical and chemical technologies, especially pesticides, where IPRs are effective; and the government was more important in other areas such as improving crop varieties. Private involvement was dominant in crop variety research only in hybrid corn, where the returns were well protected by technical restrictions on copying or reusing saved seed, trade secrets and other legal rights. Changes in the institutional environment and the form of new IPRs, combined with new scientific possibilities associated with modern biotechnology, resulted in a shift in the private public balance in research to improve crop varieties.

As the balance shifts toward private re search, new attention must be paid to old questions about whether the private investment in crop research will be sufficient, whether the allocation of those resources will be optimal, whether the results will be adopted rap idly and widely, and what role the government should play.The development of new technologies through R&D is only one element of the picture. The technologies must also be approved for commercial application and economically attractive enough to be adopted by farmers. Biotech crops have been a commercial reality only for a few years but they have made very rapid inroads in some parts of the market. In particular, pest resistant and herbicide-tolerant corn, soybeans, canola and cotton were rap idly developed and adopted in the United States and to a lesser extent in other countries . To date, the successful GM crop varieties have emphasized “input traits,” related to reducing the use of chemical pesticides or making them more effective, rather than “output traits,” related to product quality. Why has there been rapid development and adoption of GM crop ping technologies for these crops and not other important crops, such as wheat and rice? The likely reasons re late to the nature of supply and demand for new technology, and the economics of adoption.The total benefits from farmers adopting any new cropping technology are approximately equal to the benefits per acre times the number of acres affected. With pest-resistant crop varieties, these benefits come primarily from reduced costs for applying chemical pesticides and increased yields, after an allowance for regulatory requirements for refugia to manage resistance. The distribution of these total benefits between farmers on the one hand, and the technology suppliers on the other, is determined by the size of the premium charged for the use of the new technology, but this premium also affects the incentives for farmers to adopt the technology. Economic studies suggest that farm ers and biotech companies have shared in the benefits of biotech crops and that the net benefits have been large. Gianessi et al. conducted 40 detailed U.S. case studies of biotech cultivars. They estimated that in 2001, eight biotech cultivars adopted by U.S. growers provided a net value of $1.5 billion to growers, reflecting increased crop values and cost savings. They further estimated that the 32 other case-study cultivars would have generated an additional $1 billion in benefits to growers if they had been adopted, bringing the total potential benefit in 2001 to $2.5 billion. Of this annual total, the lion’s share was for herbicide-tolerant crops , followed by insect-resistant crops . These estimates do not represent the total economic impact because the geographic analysis was limited in scope, and they do not include any benefits to the seed companies and biotech firms that produced the technology. Environmental concerns. Private benefits and costs from biotech crops accrue to growers and consumers of the products, along with seed companies and biotech firms. If the new technology involves environmental risks or replaces technology that involves environmental risks, there will be additional environmental costs and benefits to take into account as an element of national costs and benefits. For instance, pest-resistant crops can reduce the application of broad-spectrum chemical pesticides, which are hazardous to farm workers, compromise food safety and impose a burden on the environment. The economic studies to date have not assessed these environmental costs and benefits. However, Gianessi et al. estimated that adoption of the eight current cultivars allowed a redution in pesticide use of 46 million pounds in 2001, and the 32 potential cultivars could have allowed a further reduction of 117 million pounds. The relevant comparison then is between the environmental risks associated with these biotech crops and those associated with the annual burden on the environment of 163 million pounds of chemical pesticides that could be avoided by growing biotech crops instead – 66 million pounds in California alone, where 185.5 million pounds of pesticides were used in 1999 Market acceptance. On the demand side, farmers will adopt biotech varieties if the perceived net benefits to them are large enough, and this depends on the perceived market acceptance of GM crops. Concerns have been raised about the possibility that GM crops may be unsafe for consumers because of allergens or other, as yet unidentified risk factors, about risks to the environment and to the economy from uncontrolled genetic drift, and about the moral ethics of tampering with nature.

In both cases, strong competition occurs between plants and microbes so that actual nutrient uptake by individual consumers is often less than their demand due to limited supply and uptake of a nutrient by one consumer suppresses the functioning of other consumers . Furthermore, as CO2 concentrations increase, nutrient competition between plants and microbes is expected to intensify. Because elevated CO2 concentrations fertilize plant carbon productivity, plants will require more soil nutrients to facilitate enhanced photosynthesis and for tissue construction . On the other hand, enhanced carbon assimilation dilutes tissue nutrient concentrations and lowers litter quality . Decomposing lower quality litter implies that soil microbes may need to immobilize nutrients to maintain their stoichiometric balance . In addition, under elevated CO2 conditions, available nutrients will progressively move from fast cycling tissues to slow cycling tissues , which induces progressive nutrient limitation that further exacerbates nutrient limitations. Although increased external nutrient inputs and accelerated nutrient mineralization rates under warming soil conditions may enhance soil nutrient availability and partly ease plant– microbe nutrient competition, these additional nutrients may be insufficient to satisfy the enhanced plant nutrient demands . To investigate nutrient competition and its effects on the terrestrial carbon cycle,maceta 15 litros different theories of plant-soil nutrient competition have been developed and implemented in Earth System Models . However, the oretical justification and observational support for these theories are rarely discussed, which may have resulted in large biases in modeled nutrient and carbon cycling.

To reconcile this inconsistency between theory, observations, and models, we focus on one overarching question in this study: Is there an observationally consistent, theoretically supported, and mathematically robust theory that is simple enough to implement in ESMs while accurately representing plant–microbe competition for nutrients? To answer this question, we first survey four existing nutrient competition theories and their implementation in ESMs . In Results, we discuss in detail these four competition theories: CT1, no direct competition; CT2, microbial decomposers out compete plants; CT3, competition depends on pore-scale soil fertility heterogeneity; and CT4, plant–microbe relative demand controls competition. Then we describe a new theory of nutrient competition based on Equilibrium Chemistry Approximation kinetics . We test our new theory together with other existing competition theories against a unique observational data set of N competition in a grassland ecosystem.To inform the development of ESM land models, observations have to satisfy two criteria. First, observations should capture plant and microbe competition at the whole-soil level, because the significance of microsite heterogeneity diminishes at this spatial scale. Second, measurements should target short-term nutrient uptake, thus enabling relatively clear separation of the instantaneous competitive interactions from other ecosystem dynamics that occur over longer time scales . Among the four existing theories surveyed, the traditional Nutrient Competition Theory assumes that plants and microbes do not compete for nutrients. This theory presumes that plants can assimilate carbon directly from the atmosphere but rely on nutrients released from soil microbial activity, so plants are carbon rich but nutrient limited . Conversely, because soil microbes decompose soil organic matter to obtain carbon and nutrients , they are relatively nutrient abundant but carbon limited.

A second reason ecologists hypothesize that plants and microbes do not compete is that microbes can directly use organic N during decomposition , while plants primarily use inorganic N . How ever, depending on their carbon use efficiency and biomass stoichiometric imbalances against substrates , microbes do immobilize inorganic nutrients and thus directly compete with plants, creating the first contradiction against the CT1 theory. Further, plants may also utilize some low molecular weight amino acids through mycorrhizal fungi associations or direct root uptake , which creates a second contradiction to the theory. However, no existing ESMs apply CT1 to represent nutrient com petition . The second theory posits that microbial decomposers out-compete plants in nutrient acquisition. This theory assumes that microbial nutrient uptake is extremely efficient , and microbes assimilate as much nutrients as they can during decomposition, provided they are not carbon limited. When carbon is limited, mineral nutrients are released as a “waste product” . This concept leads to the classic idea that plants can only use “leftover” nutrients after microbial demands are satisfied , which is why measured net mineralization rates are commonly used as a proxy for plant-available nutrients . However, no evidence exists to support its validity at the whole-soil or ecosystem level. In contrast, 15N labeling studies have demonstrated that plants can continuously acquire inorganic nutrients, even when both plants and microbes are nutrient limited . Other observations indicate that plants may even suppress microbial nutrient uptake . CT2 has been applied in several ESMs. HadGEM2 and GFDL assume that soil microbial decomposers always outcompete plants and have priority for available nutrients . IPSL and BNU-ESM also assume that microbial immobilization has priority, but apply this priority to the estimated gross mineralization flux in the current model time step, as opposed to the nutrient pool. The third competition theory applies the emerging perspective that plant–microbe nutrient competition depends on the spatial heterogeneity of soil nutrient fertility, and therefore plants do not completely lose the competition at the whole-soil or ecosystem level.

In a heterogeneous soil medium, inorganic nutrients move from nutrient-rich microsites toward nutrient-limited microsites , with roots potentially intercepting the nutrients . CT3 has been integrated into very fine-spatial scale models that explicitly consider the role of microsite soil nutrient heterogeneity, nutrient diffusion, root–microbe interactions , and microbe–microbe competition . In these models, plants do not completely lose the competition with microbes because they can take advantage of fine-scale spatial gradients between immobilizing and mineralizing microbes. The emergent responses from these models indicate that nutrient diffusion rates, sink strength ,indoor garden and competitor spatial distributions are the most important factors affecting plant competitiveness. However, these models’ fine spatial resolution is not directly applicable to ESMs. In ESMs, each soil column is assumed to be a well-mixed environment of nutrients and competitors. Such an assumption is currently necessitated, at least, by limited computational power and observations. Although ESM spatial resolutions likely will become finer, simulating microsite-level soil heterogeneity will remain impractical in the near future. In addition, a model based on CT3 may have high explanatory value but low predictive value, because it requires fine resolution observations of soil heterogeneity.In these ESMs, plant nutrient demand is simulated based on potential Net Primary Production in the absence of nutrient constraints and the plant C to N ratio ; an analogous approach is taken for microbial nutrient demand. When soil nutrient supply is insufficient to satisfy these demands, both plant and microbial demands are reduced in proportion to their respective demands . The actual NPP is then calculated by rescaling NPP demand with the reduction factor. This “relative demand” theory implicitly assumes that the consumer with higher demand will be relatively more competitive. While being simple, the CT4 predicted plant nutrient uptake is mechanistically inconsistent with measurements , although Goll et al. argued that the “demand-driven” approach requires fewer model parameters. The ESMs that apply CT4 include CLM-CN and NorESM , CLM-CNP , and JSBACH-CNP .We compared observations from the 15N tracer study with three model structures for competition: CT2 , CT4 , and CT5 . We were unable to build a model based on CT3 for the study site due to a lack of detailed information about soil N heterogeneity, root architecture, and N diffusion and mass flow rates. Further, such a complex model structure would currently be computationally intractable for ESM applications, although below we discuss a possible intermediate-complexity approach based on CT3 concepts that could be integrated with CT5 in an ESM land model. The CT2 model predicts that topsoil plant 15N uptake is very small due to large microbial nutrient demand . In contrast, because of lower microbial nutrient uptake at depth, there are more “left-over” nutrients and plant 15N uptake is relatively higher, although root biomass density decreases with depth.

Therefore, there is an increasing microbial to plant 15N uptake ratio with increasing root biomass for the CT2 model . For relative-demand-based competition , the predicted microbial nutrient uptake declines with depth, because topsoil litter substrates are nutrient depleted and microbial biomass declines sharply with depth . However, in this calculation, the whole plant nutrient demand is fixed. This constraint implies that microbial decomposers are more competitive in the topsoil than they are in subsoil, while plant competitiveness remains constant across the soil profile. Therefore, the predicted ratio of microbial to plant 15N uptake increases with increasing root biomass . The CT2 and CT4 models were unable to match the observed nitrogen partitioning between microbes and plants. Comparing CT2 and CT4 in the topsoil, CT2 predicted a much higher ratio of the microbe to plant 15N uptake, because plants do not completely lose the competition in the relative demand approach . Importantly, in our evaluation, both CT2 and CT4 resulted in nutrient competition profiles qualitatively opposite to those observed. We also confirmed that no combination of parameters for either CT2 or CT4 could reproduce the qualitative shape of the observed competitive relationship because, for both CT2 and CT4 models, the target variable UPmic/UP plant is proportional to microbial biomass . Shaping parameters only affect the steepness of UPmic/UPplant, but not the general trend. The ECA approach explicitly considers the substrates and enzymes competitive interactions throughout the profile. It captures the general competition pattern using literature-derived parameters from other ecosystems , and qualitatively and quantitatively captures the competition pattern using parameters derived for this site .The ECA representation of nutrient competition provides a theoretical and modeling construct that resulted in very good comparison with the nitrogen uptake partitioning. These predictions demonstrate that integrated across the soil profile, plants were less competitive than microbial decomposers; plant competitiveness against microbes is a spatially distinct property and there is no simple coefficient that can scale their “competitiveness”; the ECA framework offers a theoretically consistent approach to continuously update individual competitiveness; plant competitiveness is controlled by functional and structural traits ; and in the topsoil, plants might out-compete microbes and consequently suppress microbial nutrient uptake. Of course, applying the ECA competition to ESMs comes at the cost of introducing new parameters and additional uncertainty associated with those parameters. However, the ECA approach does not necessarily increase overall model uncertainty . In fact, ECA competition largely reduced the uncertainty in global-scale predictions by considering essential processes that govern system dynamics . We argue that an analogous result occurred in this analysis, i.e., that the uncertainty reduction in model structure overwhelmed uncertainty associated with new model parameters. In addition, most of the ECA parameters are kinetic parameters, which can be directly measured or optimized , implying that targeted experiments and model calibration could further reduce parameter uncertainty.Nutrient competition constantly occurs between plants and microbes in natural terrestrial ecosystems and it will likely intensify under climate change . Therefore, two fundamental questions arise: what controls the partitioning of limited nutrient resources between plants and microbes and how should short-term competition be modeled? Regarding the first question, we highlight the very few observations available to quantitatively partition nutrient acquisition by plants and microbes, and contend that such observations are critical to improve carbon-climate feedback predictions. As we showed here, the detailed 15N tracer experiment used in this study allowed us to evaluate the existing and newly developed plant–microbe N competition hypotheses, because the experiment was conducted at the plot scale and 15N was directly injected in the rooting zone . Thus, most of the observed plant N uptake pattern reflected the direct competition between roots and microbes, via nutrient carrier enzymes quantity and quality. Regarding the second question, we show here that plant and microbial nutrient uptake can be mechanistically explained as different nutrient transporter enzymes reacting with soil nutrients in a competitive manner. By linking plant root and microbial biomass density to nutrient transporter enzyme abundances, our new competition theory produces qualitatively correct competition patterns with literature-derived parameters from other ecosystems, and is easy to calibrate for specific ecosystems. Further, the linkage of nutrient competition with plant and microbial traits will allow a model to represent the competitors’ dynamic allocation of resources to acquire necessary nutrients.