July 2023 – Nature Ecrogrow

Water can be pumped during off peak hours and stored on a farm in many different ways

Operation of surface water pumps are limited by surface water availability and delivery schedules with little inherent flexibility. Dwindling surface water sources has made operation of surface water pumps even less flexible as they are dictated by water availability and not the irrigation schedule, energy cost, and/or the grid needs. The most convenient form of energy storage on a farm is not a battery or similar technology but is in the form of water storage.Soil moisture is the most common form of water storage on a farm. Adjusting the soil properties can significantly increase soil’s moisture uptake capacity. More recently, farmers in California have started a new form of water storage by flooding their fields even outside of the irrigation season. This will recharge the groundwater aquifers during times of year when excess surface water is available . Another form of water storage that can be beneficial for DR participation is above groundwater storage . On farm water storage can act equivalently as a battery, smoothing the electricity demand for irrigation. Availability of water storage allows irrigation when needed, or when it makes the most economical sense and not when water is available. The speed of an alternating current electric motor in a pump system is directly proportional to the frequency of the power supply. A Variable Frequency Drive6 takes the electrical supply from the utility and changes the frequency of the electric current,cultivo del arandano azul which results in a change of motor speed .

VFDs are most commonly installed for energy saving purposes; however, improved process control is another reason for installing VFDs. VFDs, although promising for AutoDR can pose potential disadvantages such as damage to the motor bearing and other components if operated improperly. Considerations must also be given to VFD reliability, maintenance costs, and skills of available personnel [ CITATION USD141 \l 1033 ]. VFDs are not recommended for pumps with high static head or pumps that operate for extended periods under low flow conditions [CITATION NSW171 \l 1033 ]. Therefore, VFDs are not suited for pumps that pull water from deep groundwater wells, and are best fitted for smaller surface/booster and fertilizer pumps. Figure 11 summarizes the operational characteristics of a pump with a VFD under different speeds. Note that there is no static head present in Figure 4, only dynamic head . As discussed earlier, groundwater pumps can be easily coupled with water storage and be able to shift their operations to off peak hours. Therefore, VFDs with their drawbacks for high static head systems are not the best fit for groundwater pumps. However, VFDs would be ideal for tapping into the DR potential that booster and surface pumps can provide. Given that booster pumps need to maintain a minimum pressure on the irrigation system, VFDs can allow modulation of their power and allow such systems to provide DR services to the electric grid while meeting the operational requirements of a farm’s irrigation system. According to Figure 4, a low static head pump can reduce its power demand by a third without significant efficiency losses if operated correctly.Over 57,000 farm businesses and other farms were engaged in producing renewable energy such as solar, wind, and geothermal in 2012, more than twice as many as in 2007 . Solar energy production is the most prevalent from on farm renewable energy, with an estimated 82% of farms with renewable energy generation reporting solar electricity generation capacity . With dropping prices of solar energy, agricultural industry can benefit from dual land use for energy production. Solar panels installed on an irrigation ponds can reduce evaporative losses, and solar arrays installed elsewhere on a farm can provide shading for the livestock or the farming equipment .

On farm renewable energy production can also protect farms from volatile energy prices. This trend provides an added incentive for farmers to get a better handle on the timing of their energy use, and restructure their operations to utilize larger amounts of renewable energy such as wind and solar . Much of the infrastructure and technology that can be used for AutoDR enablement, can be used for helping farms in maximizing the use of the onsite generated renewable energy. The framework put forward in this paper also helps pave the path for policy development as farms transition from being net energy consumers to net energy generators. A high renewable penetration grid requires flexible loads in order to maintain its stability. Agricultural loads, with their large magnitude can provide that flexibility as energy markets move into a future of increasingly distributed and intermittent renewable generation. However, several on farm constraints, as well as lack of appropriate market mechanisms limit farms from taking advantage of more flexible energy and water use strategies that could benefit the grower, utility, and the grid. Agricultural demand management programs have proven to be unsuccessful in facilitating the needs of the farm and helping the utilities manage their demand and reduce cost. This indicates that current programs and tariffs do not adequately account for the needs of the grid and constraints that exist on farms. New technologies and market based approaches are needed to give utilities greater flexibility and their agricultural customers greater incentives to balance the grid and meet the high penetration of renewable sources in the coming decades. To address these barriers for DR adoption, researchers and Agricultural Technology companies have focused on topics such as scientific irrigation scheduling, real time irrigation prediction using sensor data, and remote scheduling of operations. In the meantime, utilities have done very little to tailor their DR programs to the needs of agricultural operations. A common misconception within the AgTech industry is that technology alone will inherently bring all the benefits. However, technology can lead to more complications if it is not coupled with improved management and training.

In recent years, an abundance of AgTech companies , has led to a surge of promising technologies but most lack scalability and impact on the field. For example, various models of water efficiency and environmental benefits have been developed, yet they are under utilized in irrigation scheduling; at most, they help retrospectively to evaluate seasonal approaches . Another example is of soil moisture sensors being ubiquitous on the market but are not easy to handle, lack reliability, and fail to provide adequate spatial data. The same situation applies to technologies geared toward managing energy and electricity demand on farms. Several years of agricultural DR research has identified that the DR and pathways through which a farm can be approved and enabled for DR, participate in DR events, and receive compensation are complex. Most farms lack the in house expertise for going through the entire process without the help of external consultants. Without an energy or sustainability manager, it is very challenging and intimidating for farms to even begin to approach DR enablement – unless they put all their faith in a utility or aggregator in spite of their own lack of understanding. The research for facilitating higher uptake of agricultural DR has been segmented by keeping farmers, grid operators, and utilities in silos with little thought to having them talk and understand each other’s needs. Moreover, much of AgTech sector’s focus has been on yield increase and crop quality improvement and little attention has gone towards other operational aspects of the farm including irrigation energy and water management. Ultimately,arándanos azules cultivo irrigated agriculture will need to adopt a new management paradigm based on an economic objective which not only includes yield but also takes into account water and energy . The framework put forward in this paper is unique as no similar farm to grid analysis framework has been identified in the extensive literature search in the field of agricultural water and energy. The discussion put forward in this paper can be summarized in a diagram similar to what is presented in Figure 13. With the information provided in previous sections, one should be able to connect various on farm electricity consuming equipment to the appropriate grid need using available market mechanisms. This framework will allow identification of missing market mechanisms for tapping into agricultural DR potential or can shed light on technology gaps that can facilities higher DR participation of agricultural farms. Figure 13 is intended to serve as a starting point for addressing the knowledge gap that hinders farms to provide valuable DR services to the grid and benefit from untapped revenue streams. The future work should be focused on data collection that will allow better mapping of farm equipment to various grid needs through existing mechanism or developing new ones. Even though this paper will not provide an end to end solution for DR enablement at farms, but it paves the way for widespread DR participation for all significant electricity users on farms. Figure 12 illustrates a hypothetical application of the proposed framework. In the example below, actual farm load profiles are disaggregated into various end uses . Based on the information collected regarding each end use , the relevant component of the load profile can then be mapped to the appropriate grid need based on its characteristics .The federal government’s under count of nonfatal occupational injuries and illnesses for all industries combined has received considerable research and popular press attention. A US General Accounting Office report addressed under counting and suggested remedies for all industries combined. This study extends previous research by focusing on agriculture, an industry that merits special attention for several reasons.

First, although estimates vary, agriculture employs roughly 2 to 4 million people, and includes the highest share of self-employed persons in any industry. Second, agriculture is among the most hazardous industries, especially for the self-employed. Third, agriculture employs many undocumented workers; for example, the most recent analysis from the National Agricultural Workers Survey estimated 53% of all hired crop workers were undocumented. Contentious debate surrounds whether undocumented workers should be granted citizenship and the impact this may have on workers’ subsequent use of Medicaid and workers’ compensation. Fourth, many farm workers are migrants; the NAWS estimated 42% of crop workers annually traveled 75+ miles to obtain jobs. Fifth, and most importantly, agriculture poses the greatest challenge of any industry for generating estimates of under counting because of the seasonal nature of employment, and predominance of small, family-run operations. We measured the injury and illness under count as the difference between estimates from the Bureau of Labor Statistics ’s Survey of Occupational Injuries and Illnesses and our own estimates. Unlike the SOII, we accounted for the self-employed and workers on small farms as well as willful and negligent under reporting by both employees and employers. We believe our estimates are conservative, in part because we use the same criteria as the BLS to qualify a case as an occupational injury or illness. We do not include, for example, estimates of job-related cancers, COPD, and circulatory disease that far exceed those recognized by the SOII. The under count has institutional and behavioral causes. Institutional causes pertain to deliberate reasons for excluding persons. Two of these institutional causes are the exclusions of self-employed farmers on all farms and workers on farms with <11 employees from the SOII. A third institutional cause is the government’s under count of employment of farm workers in virtually all government data sets. This employment under count is widely recognized owing to the fluid and part-time nature of farm work. BLS readily acknowledges the employment under count and estimates its magnitude in supplements to the Quarterly Census of Employment and Wages. There are two behavioral causes: negligence and willful under reporting. Despite the under count, the SOII is widely cited by researchers and journalists, in part, because it has been providing the only annual national estimates of nonfatal workplace injuries and illnesses for 40 years. There are three additional data sets with relevant information, but none as comprehensive as the SOII. The National Health Interview Survey provides information on injuries, but not illnesses, nor estimates within industries. The Census of Fatal Occupational Injuries provides information within agriculture, but only for injury fatalities. The National Agricultural Workers Survey contains data on injuries but only for crop, not animal farms.The 1970 Occupational Safety and Health Act requires very high percentages of firms to record qualifying work-related injuries and illnesses, i.e., those associated with death, loss of consciousness, lost or restricted work days, or medical treatment beyond first aid.

Sprinkler irrigation has been adopted for a wide variety of crops

California farmers used modern irrigation methods, such as sprinkler and drip, to introduce advances in the use of chemical fertilizers. More recently, computerization has contributed to the more precise management of irrigation. While the emphasis on irrigation is one distinctive feature in California agriculture, perhaps an even more important feature that distinguishes this state is the selection of crops. California agriculture is the leading producer of fruits, nuts, vegetables, and flowers in the nation—and, for many fruit and nut crops, in the world. The land share of these crops has grown steadily over time. The nature of these crops, which are less important in much of the heartland of the United States, means that a great deal of the technological development in California has more in common with Florida, parts of the southern hemisphere, and regions of the Middle East , than with Illinois and Iowa. The evolution of agricultural technology in California was strongly influenced by technological innovations and other events that originated in non-agricultural sectors of the economy. During the late nineteenth and early twentieth centuries, much of the Central Valley consisted predominantly of grain-producing areas. Grains were essential for feeding the local population and their draft animals, which provided the main source of energy for transportation and farming. Early California exported grain mostly by boat, but the introduction of the railroad provided a cheaper alternative. Dried or preserved fruits and vegetables were also shipped,maceta redonda since logistical constraints prevented the export of products with a relatively short shelf life.

During the second half of the twentieth century, with the introduction of the federal highway system and great improvements in truck transportation, California began shifting toward the export of fresh fruits and vegetables. The past 10 or 20 years have seen increased airplane transportation to export high value-added, tree-ripened fruits from California to markets in Pacific Rim countries as well as along the East Coast—another step in the continuing process of supply response to improved transportation technology that began a century earlier .Subtropical crops and vegetables produced in California have had extensive technological exchange with other regions where weather and crops are similar. In the nineteenth century and early twentieth century, a significant transfer of technology came from southern Europe and Asia to California, embodied in the immigrants from Italy, Germany, France, Armenia, and Odessa near the Black Sea who settled in the San Joaquin Valley, near the Russian River, and in other areas of California. These immigrants brought crop varieties and cultivation practices from their original countries and established the foundation for many fruit and vegetable industries in California. Traffic in ideas and technology has been on a two-way street, however. Early on, for example, the wine industry in California was essentially an importer of knowledge from France and Italy. However, as the University of California developed its significant research capacities, the state evolved from being an importer to an equal trader and even exporter of agricultural knowledge. California developed its own varieties of wine grapes, stone fruits, nuts, and citrus, and some California grape varieties were even sent to France to cope with a plethora of problems in the wine industry there.

While traditionally in many Mediterranean countries almond and other nut trees were grown mostly as single trees, without much cultivation, California researchers in the Experiment Station made a strong effort to adapt many nut varieties to California conditions and to increase their intensity of production. California has become the leading state worldwide for varieties as well as production methods in almonds, walnuts, and pistachios. Additionally, realizing the relatively small markets for many fruits and vegetables, California farmers have continually sought to produce new specialty crops and develop markets for them. Transfers of technologies between California and regions with similar crops and growing conditions have continued. Drip irrigation and the production system developed around it came from Israel. Some South African entrepreneurs and Australian companies have played a major role in technology transfer.5 California has been a major beneficiary of the Bi-National Agricultural Research and Development program with Israel. This research program, with an endowment of about $200 million, has allocated a large share of its U.S. funds to California research institutes. Much of the expected economic benefit from this program has accrued to growers in the form of improved irrigation and drainage practices, the use of computerized systems in cotton production, introduction of solarization for pest control, and so on. California growers constantly benefit from varieties being developed in other countries, including high-value flower and vegetable crops from the Netherlands and, especially, the range of fruits and vegetables from Asia. The international spillovers of genetic material are not confined to exotic species, however. For instance, Pardey, Alston, Christian, and Fan showed that California has been a major beneficiary of new wheat and rice varieties developed by the International Agricultural Research Centers of the Consultative Group on International Agricultural Research . The new higher-yielding wheat varieties developed by the International Maize and Wheat Improvement Center in Mexico, incorporating semi-dwarfing genes and rust resistance, were designed for developing countries but turned out to be especially suitable for use either directly, or as parental lines, in California and Australia. Similarly, the improved rice varieties from the International Rice Research Institute in the Philippines have been relatively well suited for adaptation and adoption in California.

Essentially all of California’s rice has some IRRI ancestors.Asian-Americans have played a dominant role in California’s high-value crops, especially along the coast. While California has been a significant importer of crops and varieties, exports of crops and genetic material from California have outweighed the imports significantly. In the future, we may expect much more emphasis on the development of crops and varieties to meet Pacific Rim demands. California has by far the world’s strongest research establishment in subtropical agriculture, exporting knowledge that was crucial in the development of cotton and subtropical farming in Australia, Israel, and other countries.6 In recent years a significant transfer of agricultural technology has taken place, including processing as well as production technologies, from Northern California to Latin America, especially Chile and Mexico. NAFTA may well encourage a gradual integration of farming in California and certain regions in Mexico that produce high value crops. Finally, there has been a steady technology exchange between California and Florida, which are unique in the nation for their subtropical crops such as citrus.7Without irrigation, much of California would be a dry and nonproductive land. With irrigation, however, the Central Valley has become the most agriculturally productive valley in the world. Combined with the soils, climate, and a long growing season, water availability has brought high yields per acre for a multitude of crops. Traditional irrigation in California was based on gravity and consisted of either flooding the fields or using furrow delivery. These methods were often technically inefficient, since a significant portion of applied water was not consumed by the crop but ended up as deep percolation, runoff, or evaporated water. Modern technology has increased irrigation efficiency significantly. Sprinkler and drip irrigation can increase yields and save water, especially in areas with sandy soils where deep percolation is significant, and with uneven soil topography where problems of runoff are severe. The problem with percolation is especially serious in some areas of the Central Valley where there is an impenetrable soil layer close to the surface, which results in water logging problems. In these cases, adoption of modern irrigation methods can avoid or slow these problems. While modern irrigation tends to increase revenue by increasing productivity, it can entail higher capital costs. Producers must balance gains against costs. Studies suggest that adoption of the new methods is most appropriate in areas with high-value crops, high prices of water, and farming conditions that make them attractive. Modern technologies are not appropriate for every location,macetas redondas grandes as for example in areas with low-value crops and heavy or poorly drained soils. At present, only 25 percent of California farmland is irrigated by sprinkler, and the share of drip is 10 percent or less. Table 4 presents information about adoption of irrigation technology over time in California.While sprinklers and drip delivery systems can cope with uneven terrain, much of California’s irrigated agriculture is irrigated by flood or ditch-and furrow methods fed by gravity, especially field crops . An important element in the development of irrigation technology for these crops, and improvement in the control of water, has been the use of improved grading techniques, especially laser leveling technology. Much Central Valley farmland has been leveled over the years, making flood and ditch-and-furrow irrigation efficient and cost-effective.Irrigated agriculture in California benefited from developments outside agriculture and from the importation of technologies from outside the United States. The ability to drill deep wells and convey water under high pressure, activities important to the use of sprinkler systems, came in large part from knowledge acquired in the oil industry; learning how to pump and transfer liquid in the oil business led to developments later found to be profitable when applied to water.While sprinkler irrigation was introduced prior to World War II, the sprinkler manufacturing industry went through a period of rapid expansion after the war. The early sprinkler systems consisted of iron pipes that connected sprinklers to the main water line.

The early post-war years also saw an excess U.S. production capacity for aluminum; since then, there has been a rapid increase in the share of irrigation systems that use lighter aluminum pipes, which have enabled the introduction of movable sprinkler systems at lower cost, an attractive alternative for some field crops, including cotton. Sprinkler systems were largely promoted by manufacturers and dealers from which farmers rented equipment in early years. As they became more knowledgeable about sprinkler irrigation, farmers rented equipment less frequently and began to purchase it outright.Since different crops have different requirements, and the profitability of investment in equipment may be different, various types of sprinkler systems have evolved; this evolution also reflects new opportunities with respect to materials and equipment. Many field crops still use the removable sprinkler system. In these cases, farms do not spend much money on equipment; the pipes are simply moved from field to field, which restricts the frequency of irrigation. Higher value crops use permanent sprinkler systems, which allow quicker response to changes in weather and also permit longer irrigation cycles with lower volumes, which increases water use efficiency. In some cases, sprinkler systems are also used for frost protection. With the introduction of plastic, there has been a demand for sprinkler systems relying on plastic pipes and meters, which may be less expensive in terms of cost and easier to move, but may require more frequent replacement.The most significant adaptation of the sprinkler system was the introduction of center pivot irrigation in the 1970s. This system revolutionized agriculture in the Midwest and increased the irrigated acres in the United States by several million acres, but it has not had a significant impact on California agriculture. Center pivot irrigation is most appropriate for crops such as corn, and is most efficient when the same machinery is used for both pumping of groundwater and irrigation. This system also requires production in continuous plots of quarter sections . While center pivot might have been appropriate for crops such as alfalfa and cotton in California, reliance on groundwater for these crops is not very common, so a combination of pumping and irrigation is not likely.Drip irrigation is another form of modern irrigation that has had significant impact on California agriculture. Introduced into California in the late 1960s, drip was initially exported from Israel. This system requires a high up-front investment; therefore, it is primarily adopted for high-value crops in situations of water scarcity, and in locations where it is especially favorable. The first significant adoption of drip was in the avocado orchards of the San Diego area, where it enabled expansion to steeper hills in both San Diego and Ventura Counties. Similarly, the use of drip enabled expansion of grape production to the hills of Monterey County and throughout the Central Valley. Drip systems can be very complex.

Growers in the Napa Valley considered the use of Christmas trees as a barrier crop

The new modeling suggests that incentives or zoning may be introduced to induce industries to modify their behavior. Furthermore, in some cases optimal resource allocation, which takes into account both pollution and transportation costs, may lead to establishment of green zones separating animal production from urban areas. The disposal of animal manure in the Chino area has historically caused severe groundwater contamination problems. Dairies in this region designated certain lands as disposal areas where all liquid and solid animal wastes are disposed. In many cases, one acre of land is needed for disposing of the wastes from more than 30 or 40 cows, and most of the salt content in this waste percolates into the groundwater. The Clean Water Act was introduced in the early 1970s. One of its most important purposes was to reduce groundwater contamination and especially salinization by animal waste. The standard regulation proposed by the State Water Quality Control Board restricted the ratio of cows’ disposal acres—the tons of manure disposal compared to the animal waste produced by one cow—to be no greater than 1.5. Studies performed at the time to assess the economic impacts of this standard suggested that it would reduce the dairy cow population drastically and reduce the economic surplus that this industry generates by about 80 percent . Not surprisingly, the proposal encountered strong objections by dairy farmers and resulted in heavy litigation. An alternative proposal was to treat solid and liquid wastes separately; the solid waste was to be hauled to safe disposal areas outside the Valley,macetas plastico and restrictions were to be imposed on the disposal of liquid waste so that the original target of salt reduction could be met. On analysis this policy proposal was found to meet regional water quality targets at less than 50 percent of the cost of the original proposal.

This policy was adopted, and enabled the industry to survive for another two decades. The use of disposal areas for animal waste is not optimal and is not sustainable in the long run, however. A major challenge for the California dairy industry is to find better solutions for disposal of animal wastes. Accommodating the animal waste regulation requires investment in waste disposal facilities. Some farmers may have significant credit constraints and not be able to obtain the resources from private lenders to invest in the waste disposal facilities. Government credit provision may alleviate this problem and reduce the difficulty of adjusting to the waste disposal regulation. Macdougall et al. show that credit support policies can significantly reduce the cost of adjustment to water quality regulation in the Chino area. They also show that the ability of the dairy industry to withstand animal waste regulation is much higher in periods of low interest rate and economic prosperity and thus that regulation should be introduced in such periods. The concern with the environmental side effects has resulted in a wide variety of constraints and regulation that resulted in outcomes that are consistent with the theory presented above. Many dairies have moved from the Chino area to the San Joaquin Valley, where growers could find both larger disposal areas and better opportunities to market their manure as fertilizer. Four of the five leading dairy counties in California are now in the San Joaquin Valley: Tulare, Merced, Stanislaus, and Kings . Part of this move is certainly a shift away from the high land values brought by residential development, but much of it is also due to decreasing the environmental costs. California has not yet found the balance between transportation costs and environmental concern in locating its animal facility and managing its land resources. The design of optimal policies to control the side effects of animal agriculture will be one of the major challenges to policymakers and agricultural economists in the coming years.The Mediterranean fruit fly, Ceratitis capitata , or the Medfly, is an imported pest, infestations of which have serious consequences for California agriculture.

The 1980-81 infestation was ultimately eliminated at a great expense—reported at over$100 million—to the State of California and the federal government. A significant amount of public funds has been spent on eradication efforts for subsequent infestations. In 1989-90 there was another Medfly infestation , and findings of the Medfly have continued since. Because of aggressive eradication efforts, the impact on the California agricultural industry has been minimal compared to potential damage. However, the eradication efforts have not been without controversy. In addition, infestations to date have been in urban areas. The protocol for eradication involves a system of traps, aerial application of Malathion-treated bait, and the use of sterile male Medflies. The most controversial part of the protocol has been the aerial application of bait. This technique has raised fears and concerns among urban residents, and, coupled with diminished availability of public funds, has caused local officials, public interest groups, environmental groups, and health and safety groups to raise questions about the necessity of eradicating the Medfly. The outbreak of the Medfly in 1993-94 raised the specter of a possible embargo of California products by Japan, and probably Korea, Taiwan, and Hong Kong . This concern increased with the discovery that the Medfly had spread eastward into Riverside County near commercial citrus orchards. Japan has indicated that if a fertile female Medfly is found in a commercial orchard, it will consider placing an embargo on shipments of fresh fruit and vegetables from California. The list of crops that serve as hosts to the Medfly is quite extensive. In a 1991 production-cost study, 22 different commodities were included: apples, apricots, avocados, bell peppers, cherries, dates, figs, grapes, grapefruit, kiwis, limes, mandarin oranges, nectarines, olives, peaches, pears, persimmons, plums, prunes, and tomatoes . In 1992, these commodities represented nearly 1.6 million acres of irrigated cropland and over $4.2 billion in value of farm production. The farm value of exports amounted to $559 million, with a substantial amount shipped to Japan and other Asian countries. The assumption made in the production-cost study was that through periodic and regular applications of Malathion-treated bait, a marketable product would be produced.Increased costs would come from the application of bait and, for those crops shipped from California in a fresh state, there would be a post-harvest treatment using methyl bromide or a cold treatment to meet U.S. Department of Agriculture quarantine restrictions.

The annual increased costs were estimated to range from a low of $349.6 million to a high of $731.9 million. The reason for this range is that the effective application of pesticides is dependent on weather factors and the length of the season. The estimated cost for post-harvest quarantine treatments was $135.3 million, which includes the cost of the treatment and the loss of fruit due to treatment damage. An additional $8.1 million in transportation costs for movement to and from treatment facilities was also estimated. Hence, total annual costs of controlling the Medfly were estimated to range from a low of $493 million to a high of $875.3 million. Compared to the 1992 value of the total value of production for the crops affected, these costs are substantial. The economic impacts from a trade embargo would include effects on fresh shipments of apples, apricots, avocados, bell peppers, sweet cherries, dates, figs, table grapes, grapefruit, kiwis, lemons, limes, tangerines, oranges, nectarines, peaches, pears, persimmons, plums, and tomatoes. These commodities do not necessarily match those of the production study, because an embargo would likely include all exported commodities to the countries in question. For example, in the production-cost study, lemons were excluded; however, in the embargo study, they are considered. Also,cultivar arandanos the embargo would likely take place even though the commodities could be treated for shipment. The 1992 farm value of these products was $2.1 billion, and the farm value of total exports was $354.8 million. These crops were grown on 655,000 acres . The 1992 total f.o.b. value of shipments of these products, including both domestic and export , was $2.9 billion. The total f.o.b. export value was $605.5 million, and the f.o.b. value of shipments to Japan, Korea, Taiwan, and Hong Kong was $376.3 million, amounting to 62.1 percent of total exports for this product. Estimates of the changes in revenue from 1992 due to an export embargo vary by crop as to their significance.In most cases, the estimated change in price was small and not very significant as reflected in the lost revenue figure. However, for the citrus crops—grapefruit, lemons, navel oranges, and Valencia oranges—which were the most impacted, the estimated revenue loss was highly significant. For grapefruit, the loss in revenue is estimated to be 51 percent of the 1992 levels; for lemons, 38 percent; for navel oranges, 15 percent; and for Valencia oranges, 55 percent. The loss in revenue for all of the commodities considered was $564.2 million or 20 percent of the 1992 value of shipments. This loss represents a decrease in income to growers, packers, and shippers of the commodities involved. At the levels indicated, it is highly unlikely that any profits would result to those commodities most heavily impacted. The costs of growing, packing, and shipping the commodities would still occur.

The question that remains is how long the industries involved would continue to produce at the levels that existed before an embargo. The total impact of a Medfly infestation on the industries involved should also take into account the costs of controlling the pest. When these costs are added to the embargo estimates, they indicate even higher losses to the industry. The total impact on the commodities would range from a low of $1.057 billion to a high of $1.44 billion. These figures represent losses to all segments of the industries involved—from pesticide applications to control the Medfly, to losses in revenues due to losses in export markets and price decreases in domestic markets. In the short run, the domestic consumer would benefit from an embargo, particularly from citrus.Estimated price decreases range from no change in the case of apricots, to over 60 percent for grapefruit. How long the consumer would benefit from these price decreases would depend on how long it took for the industry to readjust its production or to find new markets. Price decreases of the magnitude estimated for the citrus industry would be expected to last no longer than two years before production adjustments would be made. In the long run, the consumer might be worse off. Producers would eventually decrease production in order to raise prices enough to regain lost revenues and adequately cover capital investments. In addition to a loss in income to the commodities affected, the California state economy would also be impacted. It is estimated that there would be a $1.2 billion decrease in gross state product and a loss of 14,200 jobs. Hence policies to eliminate pest invasions have a significant impact on both the industries affected and the general economy.The sharpshooter transfers the bacteria from an infected host plant to other plants. Once infected, yield decreases, and often the vine will die. The leaf hoppers breed over winter in riparian vegetation, ornamentals, and/or pastures, picking up the Xylella bacteria from host plants. The insects then migrate in the spring to feed on succulent vegetation, such as grape vines, infecting the vines as they spread. An infectious blue green sharpshooter has more than a 90 percent chance of transmitting the bacteria. Recent PD outbreaks in California’s Napa Valley wine grapes, one of the premier wine-producing regions of the United States, are estimated to have cost vineyard owners $46 million in 1999 . Insecticides have limited effectiveness on PD in vineyards where the sharpshooters enter each spring from riverbank vegetation. Applying insecticide to the riparian area where the insects are concentrated might control the spread of PD, but applications are constrained due to wildlife and water quality concerns. Removal of the bacterial and sharpshooter host plants at their riparian sources might reduce incidences of the disease, but the riparian vegetation may be protected by legislation. Brown et al. considered the economic impact of planting crops between the source area and the grape vines. These crops act as a barrier to transmission in order to slow or prevent the sharpshooter migration, but this strategy requires taking land out of grape production. The optimal barrier crop strategy depends on the profitability of the barrier crop relative to wine grapes and the effectiveness of the barrier crop, measured by percentage reduction in pest penetration per unit of barrier length.

Agriculture is a major industry and major employer in California

In 1994 the SWP project contractors and operators met to renegotiate the conditions for water sales among contractors and the allocation of cuts in water deliveries during drought periods. The resulting Monterey agreement also enabled contractors who overlie a state operated groundwater storage project to exchange the control of the project for surface water entitlements; these entitlements could then be transferred to urban contractors. Finally, the agreement sanctioned the permanent transfer of 130 thousand acre-feet of water from agricultural to urban users. The CVP parallels the SWP and delivers 4.6 million acre-feet of water to both urban and agricultural contractors. Urban contractors receive 10 percent of total water deliveries while the remaining 90 percent of water is diverted to agricultural contractors. The CVP was operational in 1965, but by 1992 there was considerable political pressure to modify the operation of the project to reduce environmental damage to different fish populations in the Sacramento River Delta. The resulting Central Valley Project Improvement Act reallocated water to environmental uses by cutting water deliveries by 1 million acre-feet in normal rainfall years and by 804 thousand acre-feet in critical rainfall years. The CVPIA mandated that 800 thousand acre-feet of water be reallocated to in stream uses to protect the salmon runs, while 400 thousand acre-feet of water be reallocated to wildlife refuges . Water markets in the CVP districts are limited to local sales among agricultural contractors. These sales are short in duration and are generated by differences in the water allocations between farm regions and years. Due to institutional constraints,macetas cuadradas CVP water is still largely used for agricultural irrigation despite a three-fold difference between the value of water in nearby urban sectors and agricultural sectors.

In recent years, State and Federal law have mandated a set of modifications that affect both the state and federal water projects in California. In 1996 and 1997 California developed the 4.4 Plan that aims to reduce diversions from the Colorado River to 4.4 million acre-feet over a period of 15 years. Moreover, in 2000 the Environmental Water Account was implemented by the state and federal governments. The purpose of the EWA is to regenerate the fisheries of the San Francisco Bay-Delta system while simultaneously securing water supplies to both urban and agricultural users. Both these developments have encouraged water trading.Figure 3 plots both actual transfers and regression predictions of water transfers in California between 1985 and 2001. The regression fitted to water transfer data confirms that rainfall levels have a significant effect on annual water transfers . The data also confirms a positive correlation between the time trend and water transfers. When expressed as a percentage of the mean level of water transfers, the regression time trend shows an annual growth rate of 1.26 percent over the period. We can conclude that the current data shows a steady growth in water markets despite the recent predominance of relatively wet years. In spite of the active and growing water market, Hanak points out that California’s water market only accounts for 3 percent of total annual water use. Hanak estimates that Central Valley farmers have accounted for approximately three-quarters of all water sales, while the rest of the water has been supplied from Imperial and Riverside Counties. According to Hanak, environmental regulations, rather than urban agencies, have been the major sources of the increased demand for water. Direct purchases for in stream uses and wildlife reserves constituted over one third of increased water trades since 1995, while agricultural activities in the San Joaquin valley accounted for over half of the increase in water purchases. This increase in agricultural demand for water stems from the reduction in contractual water deliveries under environmental regulations. However, municipal agencies are the principal purchasers of long-term and permanent water contracts, which constitute approximately 20 percent of total water trades.

The 2001 legislation that requires that local governments ensure adequate water supplies for development is likely to increase the urban demand for long-term water transfers.Within California there is considerable resistance to water trading which stems from communities in the source regions. These communities are concerned that water sales will generate significant “third-party” effects; i.e. trades may have an adverse impact on both local groundwater users and the local economy. These concerns have arisen from communities’ perception of the impacts of short-term water transfers in the early 1990’s, which involved the implementation of fallowing contracts by the state to purchase water for the 1991 drought water bank. Water transfers, which were accompanied by land fallowing, slightly reduced the demand for labor and other farm inputs and also decreased the supply of raw materials to local processors. Howitt estimated that losses in county income in two counties that transferred water ranged between 3.2 percent in Solano County, where 8 percent of the acreage was fallowed for transfers, to 5 percent in Yolo County, where 13 percent of the irrigated acres were fallowed. Those farmers who replaced the surface water they had sold by pumping additional groundwater were accused of reducing both the quantity and quality of water available to other users. Because groundwater resources are not regulated by the state, the implementation of the Californian water market has sparked concerns that aquifers will be subject to uncontrolled mining. The experience of the 1990’s has exacerbated another source of anxiety: local officials fear that once water has been transferred elsewhere, local communities will have insufficient money and political influence to retrieve these water entitlements . Currently, state approval is only required for water transfers pertaining to surface water entitlements that were acquired since 1914, certain types of groundwater banking and any water that is conveyed through a publicly owned facility.

The state only actively safeguards against negative economic impacts on source counties when water is conveyed through these publicly owned facilities. In the other two cases, traders are obligated not to harm other surface water rights-holders, fish and wildlife. Rural counties have attempted to protect their water interests by implementing local restrictions on water marketing in the form of local ordinances . By late 2002, 22 of the state’s 58 counties had put ordinances into effect . These ordinances mandate the acquisition of a permit before exporting groundwater or extracting groundwater to substitute for exported surface water. Individuals who wish to obtain a permit have to undergo an environmental review process. According to Hanak, the very low number of permit applications indicates that this process acts as a deterrent to water trades, rather than as a screening mechanism. Statistics for 1990 to 2001 suggest that the implementation of groundwater export restrictions reduced a county’s water trades by 14,300 acre-feet and transferred 2,640 acre-feet of water purchases to in-county buyers. Since 1996 total groundwater exports were reduced by 932,000 acre-feet or 19 percent and total water sales were reduced by 787,000 acrefeet or 14 percent .While the 1994 appellate court decision favoring Tehama County sanctioned the implementation of groundwater ordinances, counties do not have the legal authority to ban crop fallowing, although several counties have implemented such policies. According to Hanak, these counties tend to have boards that are elected by the general community,maceta cuadrada plastico as opposed to boards that only permit landowners to vote. In general, landowners are more likely to fallow land for the water market, especially when crop prices are low. Section 1745.05 of the Water Code mandates that any fallowing proposal that exceeds 20 percent of the local water supply must undergo a public review. Hanak found that water districts that implement fallowing programs tend to include restrictions in these programs that ensure that the viability of idled land is maintained and that landowners who engage in land idling are not solely engaged in selling water. In summary, a well functioning water market is seen as essential to California’s ability to adapt its restricted developed water supplies to changing demands for water. Over the past seventeen years the water market has evolved different forms and has shown steady growth despite relatively good water years. However in recent years, local resistance to water markets has taken the form of local ordinances. These ordinances need to reflect both the interests of local communities and state water users to enable the development of effective markets without imposing undue costs on local communities.Over the course of a year, some 35,000 of the state’s 750,000 employers hire a total 800,000 individuals to work on the state farms, so that about 5 percent of California’s 16 million workers are “farm workers” sometime during a typical year.

Agriculture is a seasonal industry, hiring a peak 455,000 workers in September 2002 and a low of 288,000 in February 2002. Since most farm workers are employed for fewer hours than manufacturing workers, and earn lower hourly wages, they have lower than average annual earnings. Average hourly earnings in California agriculture are about half of average manufacturing wages, $7 to $8 an hour versus $14 to $15 per hour,1 and farm workers average about 1,000 hours a year, so that farm workers have annual earnings of $7,000 to $8,000 a year, a fourth of the $30,000 to $35,000 average for factory workers.Since 1975, farm workers have had organizing and bargaining rights, but there have been elections on only about 5 percent of the state’s farms, and there are contracts on only about 1 percent. Farm worker unions have about 30,000 farm worker members; the organizing and bargaining activities of the dominant union, the United Farm Workers, have increased since founder Cesar Chavez died in 1993. Beginning in 2003, the state can require mandatory mediation that results in an imposed contract if employers and unions cannot negotiate a first agreement. During the 1990s, the percentage of unauthorized farm workers increased along with the market share of farm labor contractors and other intermediaries who, for a fee, bring workers to farms. Wages and fringe benefits generally declined in the 1990s, and farmers, fearing losses if unauthorized workers were to be removed suddenly, have lobbied in Congress since the mid-1990s for an employer-friendly guest worker program. They have not yet succeeded in winning such a program, and the debate in 2003 is whether surging Mexico-U.S. illegal migration is best managed with guest workers, legalization, or a combination of the two, so-called earned legalization, under which unauthorized foreigners in the U.S. would obtain a temporary legal status that could be converted to an immigrant visa with continued U.S. employment.Food and fiber is produced on farms, which are defined in the U.S. Census of Agriculture as places that sell at least $1,000 worth of farm commodities a year. Most of the 2.2 million U.S. farms are considered family farms, a term that is not defined officially, but a common definition is that a family farm uses less than 1.5 person-years of hired labor. Most family farms are diversified crop and livestock operations that provide work for farmers and family members year-round, and the mechanization of many farm tasks has enabled most farm families to include one or more persons employed in non-farm jobs. California farms are different because of specialization, size, and the presence of hired workers. Instead of combining crops and livestock, most California farms specialize, producing only lettuce, peaches or grapes. These FVH crops—fruits, nut and berries, vegetables and melons, and horticultural specialties that range from nursery and greenhouse crops to Christmas trees, mushrooms, and sod—require large amounts of labor for short periods of time, so large FVH farms can require hundreds of workers for 3 to 6 weeks, and only a handful the rest of the year. In California, FVH commodities occupy a third of the state’s irrigated crop land and account for half of the state’s farm sales. Producing FVH commodities with hired workers in California fields is often compared to manufacturing products on factory assembly lines. Like factories, the farms bring together people, land, water, and machines to transform seeds into crops, with agriculture’s biological production process marked by risks that do not arise in manufacturing production processes governed by engineering relationships. FVH commodities are considered “labor-intensive:” labor costs range from 20 percent to 40 percent of total production costs—higher than labor’s 20 percent share of average production costs in manufacturing, but less than labor’s 70 to 80 percent share of costs in many service industries.

California agricultural interests receive a large portion of the federal MAP funds

Specifically, the 2002 Farm Bill allows export subsidies to offset “a trade restriction or commercial requirement that adversely affects a new technology .” As Hudson points out, this may open up EEP to many new agriculture products not covered in earlier years. The DEIP subsidizes exports of milk powder, cheese, and butter. These dairy products, unlike the products that are eligible for the EEP, are subject to federal dairy price support, creating a gap between domestic prices and world market prices. The price support is administered by the Commodity Credit Corporation, which pays “bonuses” to exporters to compensate these firms for the differential between prevailing international market prices and artificially high domestic prices. The stated intention of the program is to develop export markets for U.S. dairy producers in markets where dairy is subsidized. In 2001, so-called bonuses of $1.76 million were awarded for U.S. cheese exports and $6.8 million was paid to U.S. non-fat dry milk exporters . These low figures, far below WTO ceilings, reflect the fact that relatively little of the dairy output from most U.S. producers is actually exported. Perhaps 5 percent of volume is exported, with most going to Mexico . Butter and butter oil lost DEIP funding in 2001 and 2002 due to high domestic prices and a fragile butter market, while similar market conditions eliminated support for whole milk powder those same years . As shown in table 2, DEIP awards to California producers vary widely from year-to year, depending on world market prices,garden pots ideas though the bulk of export subsidy payments consistently goes to non-fat dry milk .Table 3 lists California companies and trade associations receiving recent MAP assistance, including national or regional trade associations of which California producers are members.

While all $28 million shown in Table 5 does not flow solely to California producers and their trade associations, at least $15 million does benefit California producers through the MAP program.4 This amount alone is approximately 15 percent of the entire MAP budget in 2001 , meaning that California receives more than 15 percent of the MAP budget. Since California accounts for about 15 percent of U.S. agricultural export revenues but receives more than 15 percent of the MAP budget, it benefits disproportionately from MAP funds. FMD differs from MAP in that FMD’s stated goal is to target long-term development of overseas markets for generic commodities through trade associations rather than the promotion of individual brand products by companies. According to FAS/USDA, FMD gives preference to non-profit U.S. agricultural and trade groups that represent an entire industry or have a nationwide scope and is intended to support the export of value-added products to emerging markets . The FMD is also supposed to support a wider variety of marketing activities than MAP, allowing applicants to submit a marketing plan describing the world market for the given commodity, a marketing budget, and those promotional activities the trade association will undertake. In the latest Farm Bill, Congress increased annual funding for this program from $27.5 million to $34.5 million annually . Trade associations pertinent to California agriculture that received FMD funding in 2001 are listed in Table 4 . However, because FMD targets trade associations of a national scope, only one trade association included in the table represents solely California producers.The new TASC program is targeted at specialty crops, which are important to California. The program, funded at $2 million per year through 2007, is intended to subsidize the cost of activities such as seminars, field surveys, pest and disease research, and pre-clearance programs that may lower phytosanitary and technical barriers to trade for specialty crops .

Peanuts, sugar, and tobacco are not eligible for support. Like the MAP, this program is open to private firms as well as non-profit trade associations, suggesting that it will be vulnerable to the same criticism that MAP has faced. Table 5 lists California organizations that will receive TASC funding in 2002.Export subsidy programs like EEP and DEIP are constrained by current WTO commitments, and the California Farm Bureau Federation has taken the position that they should be phased out entirely as part of on-going WTO negotiations . However, the CFBF’s position with respect to the MAP and FMD programs is vastly different. There seems to remain a consensus in California agriculture that these programs deserve further and increased funding . Despite political support in California for export promotion programs, whether MAP and FMD actually benefit California’s international competativeness remains unclear. FAS claims benefits from these programs using a methodology that the General Accounting Office has called faulty and inconsistent with Office of Management and Budget guidelines . A 1997 study of agricultural export programs sponsored by the GAO finds that there is no conclusive evidence that these programs benefit the aggregate economy . Agricultural export programs “reallocate production, employment, and income between sectors” rather than increasing total economic activity . The original justification for these programs was to support the export of government grain stocks created by domestic subsidy programs which have since been reformed. Another stated purpose, to counter agricultural subsidies in competitor countries, remains an objective of MAP. However, the GAO finds that it is difficult to effectively target MAP funds to achieve this goal because foreign subsidies are not readily identifiable. Perhaps the most problematic element of MAP, and potentially of the TASC, is that even if it successfully increases exports of assisted commodities to targeted markets there is evidence that this is often to the detriment of unassisted products.

For example, proponents of MAP point to a projected increase of $5.30 over 40 years in walnut exports to Japan for every $1.00 spent on walnut promotion. However, another study found that while every dollar spent on walnut promotion increased walnut exports by $1.42, it actually reduced the exports of eight other horticultural products by $3.57 per dollar spent, resulting in a net reduction in U.S. agricultural exports for every dollar spent by $2.15 . Studies on meat exports to Japan are also mixed, with some concluding positive findings for beef promotion with no positive effects for pork or poultry, while others only find statistically significant increases for U.S. exports of beef offal. While the targeted overseas markets may purchase more of the targeted commodity, agricultural export programs merely benefit certain U.S. exports by displacing others and do little to increase the American share of the world agricultural market . Halliburton and Henneberry also conclude that there is little economic evidence that export promotion programs are effective. Economic theory predicts that programs like the MAP are not cost-effective uses of public budgets, and thus it is not surprising that it is difficult to find economic evidence in favor of the MAP. If the private benefits of marketing efforts exceed their cost, then firms should find it profitable to undertake these efforts without government assistance. Government assistance uses taxpayers’ money to underwrite marketing efforts with high costs relative to benefits. While well-known arguments are made for government support for investments that have “externalities” associated with them, that is,30 litre plant pots benefits that accrue to many groups whether they pay the cost of the investment or not. However, the marketing of name-brand agricultural products is not likely to be such an investment.In the 2002 Farm Bill, Congress mandated country-of-origin-labeling for fresh and frozen food commodities such as meats, fish, fruits and vegetables, and peanuts.5 The new law is an amendment to the Agricultural Marketing Act of 1946 and will impose new traceability responsibilities of uncertain magnitude on suppliers at all stages of the food marketing chain. As a result, COOL has been met with heated reactions within the food and agriculture industry, and its implementation has recently been delayed by several years. In this section we describe the COOL legislation, and suggest that current practices in the meat-packing industry will make implementation difficult. We also discuss the economics of COOL and the conditions under which this regulation could increase the profits of domestic producers. This outcome is by no means assured. Benefits to society as a whole from COOL are even less likely. As we discuss, the logic of revealed preference predicts that if consumers were prepared to pay for country-of origin information amounts in excess of the cost of providing this information, voluntary labeling schemes would be adopted.

After discussing the economics of COOL, we turn to political economy issues and review various interest groups’ lobbying positions at the time the 2002 Farm Bill legislation was passed. We next consider the international trade implications of COOL which is likely to act as a non-tariff trade barrier. Whether the rule would, if implamented, be challenged in the World Trade Organization remains unclear.The commodities that COOL applies to include muscle cuts of beef, lamb, and pork, ground beef, lamb, and pork, wild and farm-raised fish and shellfish, fresh and frozen perishable agricultural commodities , and peanuts. Under previous law, there were country-of-origin labeling requirements, but these mostly applied at the wholesale level . Shrink-wrapped packages of apples had to convey country of origin to the customer at the supermarket, while a crate of imported pears only had to indicate its country of origin to the retailer receiving the package, who by placing the pears in a bin, had no obligation to inform his/her customers of the pears’ origin. Similarly, imported meat that underwent processing in the U.S. was not required to be labeled for retail sale unless that meat was received in the exact form in which it would be sold to the consumer. The new regulation covers both domestic and imported food commodities and requires that retailers inform retail consumers of country of origin for the covered commodities. Thus, the number of businesses that must comply with COOL . Public comment was solicited during development of the program, and the Secretary was to release mandatory labeling requirements by September 30, 2004. However, as of December 2003, a House-Senate conference committee delayed mandatory compliance with COOL for all products except farm-raised and wild fish until September 2006. Strong opposition to COOL by producers and retailers is largely responsible for the postponement of this regulation. A review of the voluntary guidelines released in October reveals the complexity of the situation. According to Federal Register 67-198, to qualify for a “United States Country of Origin” label, beef, lamb, or pork must come from an animal exclusively born, raised, and slaughtered in the United States. For beef, an animal may be born and raised in Alaska or Hawaii and transported through Canada for up to 60 days before slaughter in the United States to merit a U.S. origin label. Fish and shellfish labeled as U.S. origin must come from farmed product hatched, raised, harvested, and processed in the United States or from wild seafood harvested in U.S. waters or aboard a U.S. flagged vessel and processed either on said vessel or in the United States. Seafood labels must also indicate whether the product is farmed or wild. Peanuts and perishable agricultural commodities must be exclusively produced in the United States for U.S. origin distinction. The exception made for beef from Alaska and Hawaii demonstrates some of the complications inherent in characterizing meat as the product of one country or another. Before slaughter and sale, an animal may pass through multiple countries and therefore cannot be labeled as the product of a single country. In Federal Register 67- 198, AMS addresses the problem of multiple origins, but an abundance of fine distinctions that a producer or retailer must consider indicates a potential for difficult and inconsistent labeling. For example, ground beef normally contains meat from more than one animal and thus could include beef from both the U.S. and another country. The new law will require the processor to verify the origin of each animal and determine the proportion used of each so that the label can reflect country of origin by prominence of weight. Thus, a label reading “From Country X, Slaughtered in the United States; Product of Country Y; and United States Product” would classify a product primarily from cattle born and raised in Country X but slaughtered in the U.S. followed by imported Country Y beef trimmings and beef trimmings of U.S. origin .

The growth in fresh-cut produce is rapidly reshaping the produce sector

As heightened attention has been brought to bear on obesity as a serious national health concern, in conjunction with mounting scientific evidence regarding the health benefits of fresh produce, more governmental effort is now focused on relaying positive messages to consumers about the potential health rewards of fruit and vegetable consumption. For example, there are new federal school lunch program initiatives featuring fruits and vegetables and a revamped USDA Food Guide Pyramid. The benefits of fruits and vegetables are being promoted by the Produce for Better Health Foundation in conjunction with numerous organizations such as the National Cancer Institute. Increasingly, consumer awareness of the benefits of eating fruits, vegetables and nuts is rising. Per capita consumption of fruits and vegetables, in both fresh and processed form, increased 15 percent from 1976 to 2002, reaching 324 kg, as shown in Table 2. However, examining only the total fruit and vegetable category masks important changes occurring within, such as changes in product form and relative preferences for vegetables versus fruits. Health claims benefited fresh fruits and vegetables proportionally more than processed ones, with 59 percent of total fruit and vegetable consumption in fresh form in 2002, compared to 49 percent in 1976. Fresh fruit and vegetable consumption totaled 145 kg in 2002, up 8 percent over 1989 and 29 percent relative to 1976. These gains are impressive in a developed country with a mature food market in the aggregate. Vegetable consumption, in both fresh and processed form,hydroponic channel grew much more rapidly from 1976-02 than did fruit consumption. Vegetable per capita consumption increased 20 percent to 195 kg, while per capita total fruit consumption grew by only 7percent to 128 kg.

Key forces driving the increase in vegetable consumption include the emergence of fresh-cut salads and vegetables , growth in the fast food industry with its usage of processed tomatoes, primarily for pizza, and processed potatoes, primarily for French fries.In 2002 fresh-cut produce sales were estimated to have reached $12.6 billion , with about 60 percent sold via food service channels and the remainder through retail. However, to date primarily vegetables have benefited from this trend. In 2002 the value of fresh-cut fruit sold through supermarket channels was still quite small, $238 million according to IRI, with total sales including through food service channels estimated by industry sources at over $600 million. Recently fresh-cut fruit new-product introductions have risen and fresh cut fruit post harvest technology is improving. Growing consumer demand for convenient, healthy snack foods and desserts lead some to predict that fresh-cut fruit may be poised for the same type of rapid growth experienced by fresh-cut vegetables over the last decade. California fruit shippers should benefit from this growth, both as producers and as sourcing agents. The diversity of fresh produce offerings in U.S. supermarkets has expanded at an astounding rate. The number of items carried by the average supermarket produce department increased from 133 items in 1981 to 350 items in 2001. This reflects the emergence of more diverse eating habits, and the growing demand for specialty and ethnic fresh fruits and vegetables, as well as the introduction of a myriad of fresh-cut, value-added products, designed to respond to the growing consumer demand for convenience. The abundant supply of increasingly diverse and convenient fruit and vegetable offerings should support continued growth in per capita consumption.

Exports have come to represent an increasingly important growth market for U.S. food marketers, in light of a mature domestic market. The importance of the export market varies widely by commodity and state, with a weighted average export share of 18 percent for the top 50 products produced in California in 2002 . Among horticultural crops export shares are higher for nuts than for fruit and vegetables, due to the lower perishability of nuts and California’s important role in world production. Over 60 percent of California’s almond crop is exported annually compared with 10 percent of lettuce and around 12 percent of strawberries. With certain important exceptions California is a net exporter of most of the crops it produces, even those facing import competition. Most fresh produce imports tend to enter during the off- or early-season when domestic production, including in California, is low. Trade liberalization negotiated under the Uruguay Round of the GATT and implemented under the World Trade Organization , as well as through regional trade agreements such as NAFTA, has expanded market access and strengthened mechanisms for combating non-tariff trade barriers such as scientifically unfounded phytosanitary restrictions. Advances in post harvest technology, including the development of container-level modified atmosphere technologies, have also facilitated exporting perishables to distant markets. Total U.S. horticultural exports, including fresh and processed fruits, vegetables, and nuts, were $11.3 billion in 2002, up from $2.7 billion in 1985. California firms captured a sizable share of this export growth, exporting $4.9 billion worth of horticultural products in 2002 according to USDA. However, trade liberalization has also led to greater import demand, with U.S. horticultural imports reaching $18.7 billion in 2002.

In recent years imports have grown more rapidly than exports but imports are still a small share of total U.S. horticultural consumption, 18 percent in 2001. As markets become more open, they become globalized and many California commodity sectors are increasingly impacted by changes occurring in international markets. Expanding export demand, in particular in Asia, led by Japan, in the first half of the 1990s caused producers to increase plantings of perennial fruit crops, for example. By the time this area was coming into production as of around 1995 and beyond, export markets had peaked and declined due to Japan’s economic recession and the resulting Asian flu. A growing export market in Mexico also temporarily peaked in 1995 due to an economic crisis there. Simultaneously, greater world production of many commodities also grown in California has increased competition for California firms in third country markets. The rapid emergence of China as a major producer and growing exporter of fruits and vegetables is already having a competitive impact on demand for California products in Asian markets and will continue to do so as China improves its infrastructure and export quality. China is the world’s largest producer of vegetables, apples and pears. Although most of the production remains in China to serve internal demand generated by its 1.3 billion inhabitants,hydroponic dutch buckets even a small export share can be significant relative to the international volumes normally traded in any given commodity. On the other hand, income growth should expand import demand as Chinese consumers demand a greater array of higher quality food products, including fruits and vegetables. Import demand is being further stimulated by the explosion in supermarkets which require year-round availability of produce. Indeed, a recent trend throughout the developing world away from wet markets and toward supermarkets bodes well for international fresh produce trade, and hence, for California producers. It is estimated that the 30 largest retail grocery chains now account for at least 10 percent of world food sales. Many of these chains have stores located on several continents and their global procurement practices and cold chain management investments and exigencies mean that these modern produce departments must be kept full year-round. Since no country produces all of the fruits and vegetables it needs year-round, international trade will undoubtedly expand. As some California commodity sectors adjust to new market realities, structural adjustments may occur. However, in general, California agriculture remains very competitive with imports still a small share of supply. California growers and shippers substitute capital and technology for labor, enabling them to remain competitive even in the most labor-intensive horticultural crops. The primary crops for which sizable production has moved off-shore, in this case to neighboring Mexico, are those requiring bunching at harvest, such as green onions, asparagus and radishes. Still, over the next decade it is likely that many California commodity sectors will face greater import competition and more competition in export markets. While competition in third country markets will be strong, total international trade should expand as trade liberalization continues under the WTO.The principal marketing channels in the U.S. fresh fruit and vegetable marketing system are shown in Figure 1. Final value in 2002 is estimated to be at least $81 billion with roughly equal amounts distributed through food service and retail channels and around 2 percent comprised of direct farm to consumer sales.

In California, there are about 400 Certified Public Markets and many fresh produce growers participate in these markets for at least a part of their sales. Produce sold in retail or food service outlets may be procured directly from shippers or from wholesalers operating in terminal markets or in independent warehouses in local communities. Terminal markets have steadily declined in importance since the 1950s. Today there are major terminal markets serving only 15 cities, and these markets primarily handle the residual fresh market domestic production that cannot be marketed directly to retail or food service buyers. The largest terminal markets tend to be located near port areas since many imports are still handled by importers/intermediaries physically receiving the product upon arrival to the U.S. Terminal markets are no longer a factor in the distribution of processed food. The decline in terminal market share is largely a result of the increased buying power of integrated wholesale-retail buying entities, which operate large-volume centralized buying operations, and enhance efficiency by purchasing directly from the source, bypassing the wholesaler and thereby avoiding intermediary margins and handling costs. Also, the retailer- or food service-buyers are able to communicate directly with suppliers concerning important issues such as desired product quality, safety/traceability, packaging characteristics and shipment timing, improving their management of the supply chain. For fresh products, direct production-source-to buyer shipments have the additional advantage of not breaking the cold chain, better preserving product quality. Brokers may be used by either buyers or sellers at any level of the distribution system. Most brokers do not take title to or physically handle the goods, and, rather, assist in making the sale and possibly arrange transportation and other logistics. Their role had grown in importance since World War II. However, retail consolidation has been reducing the role of brokers as buyers seek closer relationships with preferred suppliers with strong category management skills. Today successful brokers tend to be those with global sourcing capabilities and account-specific service-orientations, including category management, designed to meet specialized buyer needs.Turning now to the opposite end of the marketing system, farm production of most commodities in California remains atomized in the sense that producer volumes, although often large in absolute terms, are small relative to the size of the market. It is estimated that there are about 16,500 fruit, vegetable and nut growers in California producing about half of the total volume of these crops grown in the U.S. However, most fresh produce growers don’t market their own produce, marketing instead via shippers acting as agents. Most shippers are large growers that have integrated their operations downstream into the marketing of their own production and the production of other growers—hence their designation as forward-integrated “grower-shippers.” These grower-shippers generally control harvesting, packing, and cooling, and arrange for domestic and export sales, transportation, and promotion of production. They are the dominant type of marketer of California fresh produce. According to the Red Book Credit Services there are around 5,000 fresh produce shippers in the U.S. as a whole, with about 900 located in California. These shippers are selling to an estimated total of 1,079 principal buyers, including 267 retail chains, 188 produce wholesalers, with the difference accounted for by independent retailers and other types of buyers. The bulk of retail chain purchases are being made by 161 retail chains each selling at least $64 million in 2001 . Consolidation at the buying end of the food marketing system has driven consolidation at the production level. Today’s large, integrated wholesale-retailer and food service buyers demand more services from their suppliers, tailored to their specific needs, including: category management, ripening and other special handling and packaging, including private labels, and year-round availability of a wide line of consistent-quality fruits and vegetables. Grower-shippers have responded with improved communication and information management programs and by becoming multi-regional and multi-commodity in focus.

Public land ownership is highest in the mountain and desert regions

Today’s agricultural bounty consists of hundreds of commercial agricultural commodities and products sold in every conceivable form at markets ranging from local roadside stands and farmers’ markets to distant markets around the world.The challenge to California farmers and ranchers has always been to match available, and often limited, physical, human, financial, and managerial resources to produce and market alternative outputs chosen from a long and constantly evolving set of potential agricultural commodities and value-added products. Investment and management decisions often involve the integration of production with other economic activities. The highest and best use of resources available to California’s agricultural decision makers requires frequent re-examination of the criteria of the numerous possible uses that are legally permissible, physically possible, financially feasible, and maximally productive. In the dynamic setting of California agriculture, changes are frequent, and often dramatic, as producers and marketers recurrently assess alternatives and make decisions that change important features of the state’s agricultural sector. A half century ago, University of California Dean of Agriculture Claude B. Hutchison in his preface to the book California Agriculture noted the difficulty of measuring the diversity of agricultural production in California even then. He compared the existence of 118 distinct types of farming areas in California in 1946, to substantially lesser numbers in other important agricultural states: 8 in Illinois, 12 in Kansas, 20 in the huge state of Texas, and 25 in Pennsylvania,nft system the state with the next highest number of farming areas. He also noted that only 6 percent of California farms had been classified by the 1940 Census as being general field crop and livestock farms of the sort characteristic of the Midwest Corn Dairy Belt.

“The other 94 percent are distinctly specialized farms, farms devoted largely to the production of a single commodity…Such concentration of effort or specialization calls for outstanding technical and scientific knowledge as well as familiarity with good business methods and procedures” . The developments of the past half century have accelerated greater diversity in types of farming and number of commercial commodities or products. This chapter portrays some of the current dimensions of the state’s diverse agricultural sector by first discussing the characteristics of the major agricultural production regions of California. Natural endowments and man-made infrastructures, in part, determine the nature of agricultural activity within each of the regions. Comparative advantage varies from region to region, and many crops are grown in several regions for reasons of temporal and geographical diversification. A second section discusses the changing composition of agricultural production from extensive to more intensive, higher investment, and higher valued crops. Finally, in the third section, a discussion of the state’s “Top Twenty” agricultural commodities gives better understanding of the nature of agricultural production in California. Nevertheless, the following pages, constrained by time and space considerations, are obviously nothing more than a brief introduction into several ways of examining the diversity of California agriculture.Landforms, hydrography, and climate primarily comprise the physical resources available to farms, ranches, and agribusinesses. Augmented by inputs of production capital, management, and labor, and by private and public investments in institutions and infrastructure, the physical resources importantly characterize the state’s agricultural production regions. California is a large state, the second largest in the conterminous United States. Within such a large geographical area, variations in physical resources are often extreme. For example, normal annual precipitation ranges from only 2.75 inches at Imperial in the southeastern comer of the state to over 100 inches of rain in the northwest corner of the state and at higher elevations in the Sierra Nevada and Coast ranges.

The availability of natural rainfall and snow melt fostered early irrigation development on the western slopes of the Sierras. The uneven seasonal and geographical distribution of surface water led to early private, and later governmental, investments in storage and conveyance systems. Both the highest and lowest elevations in the conterminous United States are found in California—within 75 aerial miles of each other.Climatic regions range from hot desert to alpine tundra. While most of the state’s population and much of its agricultural production occur in areas characterized by a Mediterranean climate, many of its agricultural areas in the San Joaquin Valley and in southern interior areas are located in steppe or desert climatic zones.Growing seasons range from year-round frost-free areas along the coast to relatively short seasons in higher elevation mountain valleys. The more than 700 soil series in California also reflect vast variations in age, parent material, and natural vegetation, in addition to the influence of climate and topography. Residual and transported soils vary greatly in depth, permeability, water-holding capacity, and nutrient-supplying capacity. For these and other reasons, the great variation in the physical resources available to agriculture across the state is more than sufficient to bear out the “any-crop, somewhere” maxim. Figure 1 shows California agricultural production regions delineated along county boundaries.For the most part, these regions are characterized by different resources and land uses, with the exception of valley versus mountain-type lands found along the boundary between the Central Valley and the Sierra Nevada region.8 Forty-nine percent of California lands is in public ownership, most of it controlled by the federal government .Conversely, the most agriculturally important regions have the highest private ownership levels, ranging from 71 percent in the San Joaquin Valley to about 80 percent in the Central Coast and Sacramento Valley regions. Statewide, 28 percent of the land area is in farms. Of the land in farms, 39 percent is cropland; and of the land in cropland, 81 percent is irrigated. The 1997 Census tallied 74,126 farms, which averaged 374 acres in size and sold an average of $311,000 of farm products per farm.

The size and value-of-sales statistics include both small, part-time and larger full-time farm units.Among regions, the highest average per acre sales were reported for the more intensive South Coast and South Desert subregions and the San Joaquin Valley region. The following discussion includes brief descriptions of California’s agricultural production regions as denoted in Figure 1 and summarized in Table 1. Regional values of agricultural production are based on 2001 crop reports prepared by County Agricultural Commissioners. Regional production is distributed among five categories: Field crops, Fruit and Nut crops, Vegetable crops, Livestock, poultry and products, and Nursery, Greenhouse and Floriculture crops .Consisting of the nine counties in the three northernmost production regions, the North region is in the main a relatively unimportant agricultural area of the state, even though it contains about a fifth of the state’s land area. More than half of the land area is in public ownership, and private forestry is a significant land use. Relatively small proportions of land are in farms , and of that land only 20 percent is cropland. Cattle and sheep operations, the most important component of the region’s overall agricultural economy, utilize a combination of owned land, a portion of which is typically devoted to hay or irrigated pasture production, and leased public rangelands, commonly used for summer grazing. Some dairying is still found in coastal areas. Field crop production,hydroponic gutter which includes rangeland and pasture for livestock, contributed 34 percent of the value of production in 1995, and livestock production itself amounted to another 28 percent. Some highly productive farming areas include the North Coast grape growing region in Mendocino County and the Tulelake district and mountain valley areas of the northeast, where potatoes, alfalfa hay, malting barley, durum wheat, and sugar beets are regionally important cash crops.This production region consists of a number of highly productive areas with coastal climate and fertile soils devoted to high-valued vegetable, fruit, and nursery production, as well as less productive dryland farming areas, all of which occur in relatively close proximity to the north-south Coast Range of mountains. Since early settlement, the Central Coast has been a very important agricultural region of the state.However, significant acreage has been lost to urban development as California’s population has grown. For example, farmland in the once highly productive Santa Clara Valley has been almost totally displaced by urbanization; having lost its historic reputation for tree fruit and nut production, the region is now widely known as the “Silicon Valley,” a center of the computer and electronic industries. Because of agreeable climate and other coastal amenities, pressures for urban development continue in many locales. Despite the inclusion of the important Napa and Sonoma County wine grape growing areas north of San Francisco, and the important vegetable and wine grape production areas of the Salinas Valley and Santa Maria and other coastal areas of the south, only 22 percent of the Central Coast land area is in crop land.

About half of the cropland is irrigated. High valued vegetable production, mainly in Monterey, Santa Cruz, San Benito, and San Luis Obispo counties, contributed 53 percent of the value of production from the Central Coast production region in 1995; fruit and nut crops contributed 23 percent. Major vegetable crops include almost all of the vegetables from A to Z .Wine grapes, strawberries, and raspberries are the major fruit crops. Expansion of high valued production has exacerbated surface and groundwater supply concerns. Producers in this region are highly specialized and often use very sophisticated technologies in production and post-harvest activities. Nursery products are important in several of the counties. Dryland farming and livestock activities on the more extensive farming operations contribute only a minor portion of the region’s value of production.The northernmost part and the smaller component of the Great Central Valley, the Sacramento Valley has the highest proportion of land in private ownership of any production region of the state. While urbanization pressures are substantial in the southern portion of the Sacramento Valley, most of the region continues to be heavily dependent on agriculture. Eighty-two percent of Sacramento Valley cropland is irrigated. Irrigation water sources include private and cooperatively developed surface water supplies along the western slope of the Sierras, riparian sources along the major rivers, e.g., the Sacramento, Feather, Yuba, Bear and others, and more recent additions of federally developed water supplying the western valley via the Tehama-Colusa Canal. The Sacramento River and its tributaries are the initial components of the conveyance system for federal and state water systems which, from the Delta southwards, delivers surface water via pumping plants and canals to the San Joaquin Valley and Southern California for agricultural, municipal, and industrial uses. Groundwater sources are also significant. Cooler winters, higher rainfall, and less productive soils than the San Joaquin underlie the continued importance of field crops in the Sacramento Valley. Rice is grown in areas with more impervious basin soils; both wheat and corn are included in irrigated crop rotations; and alfalfa, dry beans, sunflowers, safflower, and vine seeds are among other important field and seed crops. Field corn is grown extensively in the Delta. A variety of fruit and nut crops—mainly almonds, peaches, pears, prunes and walnuts—are grown on the deeper, better-drained and more fertile soils of the region. Fruits and nuts amount to 33 percent of the region’s value of production in 1995. Vegetable crops, mostly processing tomatoes, contributed 16 percent, and livestock and livestock products, an additional 11 percent, of the regional production total.About a third of California’s farmland and 55 percent of its irrigated lands lie in the San Joaquin Valley. Nearly 90 percent of valley cropland is irrigated. The eight counties of the San Joaquin Valley accounted for $12.75 billion of the $22.1 billion total value of California agricultural production reported for 1995 . Unlike the Sacramento Valley, the San Joaquin does not have a single river system that runs through the entire valley. The southern portion of the valley is two lake basins, historically fed by seasonal runoff from the Sierra Nevada Mountains to the east. Early farming depended on private and cooperative development of water supplies from Sierra rivers to irrigate alluvial lands on the east side of the valley, and on the reclamation of the Tulare and Buena Vista Lake Basins in the south valley bringing more acreage into agricultural production. In the post-World War II period, federal and state surface water development brought additional water supplies to the most southern area and to the entire western San Joaquin Valley, which had formerly depended on limited and often poor quality groundwater. Because much of the valley is either of a desert or steppe climatic type, irrigation is the major factor that has made the San Joaquin the most extensive and productive of the agricultural regions of California.

Urban and peri-urban agriculture is growing as urbanized areas expand

Urban agriculture occurs within and near the built environment, with high proportions of surrounding impervious surfaces such as buildings and roads . Urbanization fragments habitats and reduces the abundance and diversity of organisms . Many of the affected organisms are beneficial to urban agriculture and the provision of ecosystem services such as pollination and biological control services . Biological control of pest insects is an important ecosystem service for urban farmers due to pesticide use regulation in cities and rejection of chemical management practices for health and environmental reasons. In the absence of chemical controls, agroecological pest management practices are frequently adopted. Agroecological pest management is a proactive ecosystem services based approach that aims to reduce pest abundance and crop damage by increasing natural enemy populations through agroecosystem diversification . However, landscape fragmentation and surrounding imperviousness can often negatively affect the regulatory ecosystem services APM relies upon . While most off-farm landscape effects are not within the control of urban farmers, on-farm diversification practices are. Substantial research and published literature have investigated the impact of diversification practices to increase biological control of pest insects on rural farms, but less attention has been focused on the effects of diversification in the fragmented landscapes innate to urban agroecosystems . This chapter focuses on the effects of floral provisioning on parasitic Hymenoptera and the ubiquitous cabbage aphid , specifically,30 plant pot the impact of floral provisioning on PH populations vis-a-vis the enemies hypothesis and the nectar provision hypothesis .

The nectar provision hypothesis was proposed to explore the effects of floral-based diversification schemes on the contributions made by PH to biological control services. Heimpel and Jervis posit that with increased accessibility to nectar-producing plants, PH should respond with increased fitness, resulting in elevated levels of localized biological control . Many PH species have been documented feeding on a wide variety of flowers . Nectar, pollen, and extrafloral nectar are essential sources of carbohydrates, proteins, lipids, and minerals for PH . Nectar provisioning has been shown to play an important role in increasing parasitoid longevity, fecundity , abundance, and diversity , as well as increase rates of parasitism . Despite documented positive outcomes for parasitoid fitness and increased rates of biological control, floral provisioning does not always result in improved biological control services from PH . In response to confounding results regarding floral manipulations, researchers have proposed several concepts to explain these inconsistencies: 1. PH may utilize floral resources but then disperse to reduce the risk of hyper- or super-parasitism, other mortality, and inbreeding among offspring ; 2. parasitoids may already have enough local floral resources, and floral manipulations may not be introducing a limited resource ; 3. pest insects utilize floral resources more effectively than parasitoids ; 4. diversification strategies might make it difficult for parasitoids to find hosts in increasingly heterogeneous landscapes ; and lastly, 5. many factors determine the ability of PH to use floral resources, including wasp body size, mouthpart morphology, floral structure, and nutritional value . A disconnect between plant species and parasitoid feeding characteristics may limit the opportunity of PH to utilize these floral resources . The extent to which these conditions affect PH in urban areas is still being explored.

Generally speaking, the inclusion of flowers into urban agroecosystems to supply nectar for PH should yield effective results in the context of APM. However, inconsistent results regarding the nectar provisioning hypothesis and effects on biological control services have complicated the implementation of floral provisioning practices for farmers. Of all potential remedies for inconsistency regarding effects of floral provisioning, the concept of functional biodiversity has been championed for its potential to influence habitat manipulations that are targeted toward specific ecosystem services or to particular natural enemies. Understanding the linkages between potential PH feeding preferences and specific agroecosystem components could help farmers “fine-tune” their production systems to maximize biological control services. Morphology, bloom time, floral area, and the amount of pollen and nectar resources provided by a given plant species have all been shown to either positively or negatively impact natural enemy populations . Gaining a better understanding of the range of flowers most likely to be utilized by and positively affect PH populations and biological control services may enable practitioners to tailor management practices . To better understand the effects of floral provisioning on PH richness and abundance and potential feeding preferences, we conducted an in-situ flower survey using an improvised D-vac insect vacuum fitted with a lined and filtered five-gallon bucket that wholly covered flowering plant inflorescences. Each sampled plant was visually assessed for spatial relationships regarding other herbaceous cover and was only sampled if it was standing free of additional herbaceous cover and flowering plants. In addition, each plant was visually assessed for pest infestations and was not sampled if pest infestations were visible. We vacuumed three plants of each flowering plant species present at a farm location. Multiple samples were collected during a farm visits, but varied due to available specimens.

Sampling occurred once every thirty days during the same time intervals during each visit. Results from the 2018 survey informed flowering plant selection for the 2019 sampling season. Each plant species that yielded very few or no PH during the 2018 sampling period was excluded from sampling in the following year; 13 flowering plant species were sampled . Each sample was stored in a deep freeze until processed by extracting all PH and identifying them to sub-family as per previous literature . Parasitic Hymenoptera identification was accomplished using Goulet et al., for all groups and Gibson et al. for Chalcidoidea and Dangerfield et al., for Braconidae. Collected specimens that were damaged were identified to morphosubfamily.Aphid abundance, parasitism, and plant damage observations were performed over two growing seasons on commonly grown brassica cultivars: kale, broccoli, collards, and tree collards. Individual plants were randomly selected and identified to cultivar. If possible, we only observed plants that had not been heavily harvested. The major insect pests of interest were cabbage aphids , a common agricultural pest of Brassicaceae. Aphid abundance was measured on each plant by selecting three leaves and recording the number of apterous, alate, and parasitized aphids . The percent of mummified aphids per leaf was used as a measure of biological control services by parasitoid wasps. A qualitative assessment of pest damage on brassicas was completed using a high, medium, and low scale based on familiar concepts of marketability. High damage corresponded to a leaf that would be unmarketable, medium damage had some damage but would still be purchased by a consumer, and low damage had little to no visible damage. Two agroecological practices that increase on-farm diversification, floral provisioning,30 planter pot and crop richness were measured three times: early-season , mid-season , and late-season . Crop richness was measured by using 8m transects across cropping systems. Any crop plant that touched the transect line was considered, including different cultivars of the same species . Three transects were completed on small farms, six on medium farms, and nine on large farms. We collected data for crop richness three times during the growing season over the two years of the study. Floral richness was recorded seasonally, similar to crop richness. Every on-farm, non-crop flowering plant was recorded and identified to genus. Generalized linear mixed models were constructed for each of the following response variables: Total parasitic Hymenopteran abundance, super-family, family, and subfamily abundance, and total PH diversity. Selected fixed effect explanatory variables included: floral richness, floral species, year by season, and site as a random intercept. Using the fitdistrplus package in R, parasitic Hymenoptera count data were plotted and examined to determine the best probabilistic distribution for the GLMM modeling; a Poisson distribution with a log link function . Models that had response variables significantly affected by floral species were further analyzed using the non-parametric KruskalWallis test with posthoc Dunn’s test to determine floral species that had the most significant influence on the response variable . Aphid data were analyzed to test for differences in aphid abundance, parasitism rates, and crop damage.

Explanatory variables examined were year and season, floral richness?Aphid count data were assessed using the fitdistrplus package in R to determine the best probabilistic distribution for the GLMM modeling; a negative binomial distribution with a log link function . The final GLMM was constructed with glmer.nb using crop and floral richness, date and year as fixed effects and site as the random effect. We constructed mixed-effects models using the lme4 package in R . After fitting a series of GLMMs based on predictors expected to affect response variables, the model with the lowest Akaike Information Criterion score was selected. All GLMM model residuals were simulated from the fitted model using the simulate Residuals function in the package DHARMa to test for dispersion and model fit . Using the effects package in R, a partial regression plot was constructed for each predictor variable included in the final GLMMs . To better understand the nectar provision hypothesis and the effectiveness of floral-based habitat manipulations, we used PH abundance and richness on flowering plants to indicate parasitoid feeding preferences. Our results showed that floral species were not a strong indicator of increased abundance or richness at any measured scale of PH. Only one PH family, the pteromalids, was found in more significant quantities on nettles. Using a non-parametric test, PH diversity was shown to increase on marigolds and nettles, a response documented by previous floral provisioning research . Laboratory experiments have shown floral feeding preferences in parasitoids , but in-situ results have been less clear . Our results show that our collected PH had a very weak response to floral species, and in some cases showed a negative relationship to floral richness. Several factors may singularly, or in aggregate, explain this absence of floral preference in situ: 1. floral resources incorporated into urban gardens and farms are not selected for their functional diversity but that of other traits, such as attractiveness and availability ; 2. in-situ food resources may present a greater variety of acceptable foods unlike no-choice feeding trials; and 3. some sampling bias may have occurred when using the vacuum on inflorescences as the vacuum may be more likely to capture smaller parasitoids which may be able to exploit a broader range of nectaries or may be feeding on other food items such as honeydew . Many parasitoids also feed on the same plant as their host, which may bias visitation by family and sub-family. A negative PH abundance response to increased floral richness may be a result of dispersion to reduce the risk of hyper- or super-parasitism, other mortality, and inbreeding among offspring . Our research showed a weak relationship between increased PH richness on marigolds and nettles and an increased abundance response with pteromalids on nettles compared to other PH taxa. Marigolds have a history of being utilized as a beneficial flower in the gardening community and are grown for cultural and aesthetic reasons. Nettles are not typically grown intentionally, and in the few location’s nettles were sampled, they were unintentional but preserved in non-crop areas. Nettles, in this case, may be an example of a non-selected floral species with a higher level of ecosystem function than species selected for other traits. Additionally, aphid parasitoids, specifically Aphidius, have been found in higher abundance on nettles due to the occurrence of the stinging nettle aphid, Microlophiurn carnosum . It is unclear what connection pteromalids may have in this ecology. It is possible that nettles sampled had infestations of aphids that remained obscured due to the obstacles associated with close inspection of stinging nettles. Despite these findings, anecdotal relationships between floral species and specific PH species indicate these relationships should continue to be explored to better understand parasitoid feeding preferences, floral occupancy, and farm scape mediated biological control. To assess the second criterion of the nectar provision hypothesis, a demonstratable reduction in pest impacts, we looked at aphid abundance, rates of parasitism, and overall crop damage on brassicas. Our results show that farms with increased floral richness have lower aphid counts per plant. We did not record a reduction in crop damage nor an increase in aphid parasitism with increased floral richness.

How Long Does Hydroponic Lettuce Take To Grow

The growth time for hydroponic lettuce can vary depending on the specific lettuce variety, environmental conditions, and the desired size for harvest. However, lettuce is generally known for its relatively quick growth compared to many other crops. Here are some general guidelines for the growth time of hydroponic vertical lettuce tower:

Leaf lettuce: Leaf lettuce varieties, such as green leaf, red leaf, and butterhead lettuce, are typically harvested at the baby leaf stage or as mature leaves. Baby leaf lettuce can be harvested as early as 3 to 4 weeks after planting, while mature leaf lettuce may take around 6 to 8 weeks to reach full size.
Romaine lettuce: Romaine lettuce, also known as cos lettuce, takes slightly longer to grow compared to leaf lettuce. It usually takes around 8 to 10 weeks for romaine lettuce to reach maturity.
Bibb and butterhead lettuce: Bibb and butterhead lettuce varieties, which have more compact heads, generally require 8 to 10 weeks to reach maturity. These lettuces are harvested when the heads are fully formed and compact.

It’s important to note that these timeframes are approximate and can vary depending on various factors, including temperature, light levels, nutrient availability,hydroponic nft channel and specific lettuce variety. Additionally, some growers may choose to harvest lettuce at different stages, such as baby leaf stage, for a continuous harvest rather than waiting for full maturity.

By monitoring the growth of the plants and observing the development of the lettuce leaves or heads, growers can determine the optimal time for harvest based on their preferences for size, taste, and texture.

Self-reported information on personal or family history of kidney disease was collected

All study procedures were approved by the University of California, Davis Institutional Review Board. AKI during the work shift, defined by a specified increase in serum creatinine from the preshift to the post shift measure, was the primary outcome of interest. Using the recommended definition and stages of injury from the Kidney Disease: Improving Global Outcomes group,AKI was defined as an increase of the post shift serum creatinine by ≥0.3 mg/dL or ≥1.5 times the preshift creatinine. AKI staging was based on the following: stage 1 ; stage 2 and stage 3 . Variables thought to be associated with AKI were selected a priori based on a review of the literature and feasibility of collecting data in the field. Demographic variables included sex , age and level of education . Clinical data were also obtained. Estimated glomerular filtration rate was calculated using preshift serum creatinine based on the Chronic Kidney Disease Epidemiology Collaboration equation and categorised as ≥90 mL/min/1.732, ≥60 to <90 mL/min/1.732 or <60 mL/min/1.732 . Body mass index was calculated from preshift height and weight measurements , and classified based on WHO recommendations as normal weight , overweight or obese . Diabetes status was defined by standard categories of HbA1c:no diabetes , prediabetes or diabetes . Seated blood pressure was categorised as recommended by the Joint Commission:normal blood pressure , prehypertension , or hypertension .Variables related to occupation included years in agricultural work , how the worker was paid or salary, and the farm task they engaged in most during that day.Descriptive statistics were calculated for the outcome and potential risk factors,hydroponic growing in pooled models and stratified by sex. Differences between males and females were tested using χ2 tests.

We determined AKI classification using the three stages of AKI. We then estimated the association of categories of per cent change in body mass and heat strain with AKI categories. In regression models, we dichotomised AKI as ‘any’ versus ‘none’. Logistic regression models assessed the associations between AKI and predictor variables. Because of concerns that sex might modify the effects of interest, we fit models stratified by sex in addition to pooled models. To aid in interpretation of the main effects in models which included interaction terms, we centred the PSI at a selected reference point and subtracted 4 from each value of PSI. We defined heat strain as a continuous variable based on the PSI. Our first model estimated the age-adjusted association of body mass change and heat strain on AKI. The second model added physiological or traditional risk factors, including weight class, diabetes status, hypertension status, and personal or family history of kidney disease. The final model added occupational risk factors, including years in farm work, payment method and farm task. We tested for effect modification of significant predictors . The Akaike and Bayes information criteria are model goodness of fit measures that incorporate a complexity penalty in favour of parsimonious models, with smaller values indicating better model fit. We report these measures for all models and used them to select the final model, with preference going to Akaike in case of conflicting results. Investigator beliefs about possible causal linkages were encoded using directed acyclic graphs, to develop a parsimonious set of candidate covariates . Covariates were also screened for variation. Those without sufficient variation were dropped . For some categorical variables, levels were combined to increase the precision of estimates involving these factors. For example, diabetes was collapsed to HbA1c<5.7 vs ≥5.7. Farm task was also collapsed to picking versus other. Participants with missing values for critical variables were dropped . A total of 300 participants were enrolled in the study. Five participants were missing either preshift or postshift creatinine measures, and an additional 12 were missing variables required for calculating heat strain, and the final analyses therefore included 283 participants . Our sample consisted of 182 males and 101 females, and the majority of the participans were from Mexico . The mean age was 38.6 years . Most participants were overweight or obese and were prehypertensive or hypertensive . Most had eGFR≥90 mL/min/ 1.732 , were not patients with diabetes or prediabetes , and had no personal or family history of kidney disease .

The mean maximum temperature was 38.0°C , and the mean maximum heart rate was 130 bpm . Statistically significant differences between the two sexes are shown in table 1. Overall, men reported higher levels of education than women. Men also had higher rates of prehypertension or hypertension than women . Men reported more years working in agriculture . There were also differences in the payment method, with 30.8% of men being paid by the piece versus 19.8% of women . Using changes in serum creatinine from preshift measures to post shift measures, 31 participants met KDIGO criteria for stage 1 AKI . An additional four participants met criteria for stage 2 AKI. Stratified by sex, 22 males and 13 females met criteria for AKI. Among men, 10 experienced heat strain, as estimated by PSI≥7.5, and 3 of those met criteria for AKI. No women experienced heat strain. Additionally, most of the sample experienced loss of body mass during the shift, but most did not lose more than recommended by OSHA. For example, 118 of men and 53 of women lost <1.5% body mass. However, five of the men and two of the women who lost ≥1.5% body mass met criteria for AKI. There were no statistically significant unadjusted associations of AKI with either heat strain or the change in body mass classification. Table 3 shows the results of logistic regression models. In the age-adjusted and sex-adjusted model, heat strain was associated with 1.29 adjusted odds of AKI . In this model, stratified by sex, the association among men was significant , but not among women. In the model adding physiological characteristics, the association of heat strain on AKI was virtually unchanged . Obesity was significantly associated with AKI . In the stratified model, men who were overweight or obese had reduced odds of AKI . There were no statistically significant associations among females. The addition of occupational characteristics in the final model did not appreciably change previous associations. However, piece rate work was associated with 4.24 adjusted odds of AKI . In stratified models, this association was not significant among men. Among females, the adjusted odds of AKI rose to 102.81 . Additionally, there was a statistically significant association of years in agricultural work to AKI among females . We modelled BMI as a continuous variable and found an inverse linear association with AKI: for every one-point increase in BMI, the odds of AKI went down 0.09 .

In subsequent pooled models, we added the interaction terms. None were statistically associated with AKI, nor did the additions appreciably change the estimations. Additionally, the model-fit statistics did not improve with the addition of the interaction terms . Incident AKI occurred in 35 participants in our sample of 283 California agricultural workers in the summer of 2014, in 22 of the 182 males and 13 of 101 females . In males, heat strain as estimated by PSI was associated with increased odds of incident AKI. In females, heat strain measurement was not associated with AKI, but occupational factors such as years in agricultural work and being paid by the piece were associated with AKI. While manifested differently between the two sexes, these findings together suggest that incident AKI is an occupational risk factor of agricultural work. The association of heat strain and AKI is not surprising, given that occupational heat strain has been associated with increased risk of renal insufficiency.In particular,hydroponic dutch buckets heat strain has been named as one of the potential risk factors for the development of a chronic kidney disease identified among agricultural workers in Central America, India and Sri Lanka.Moreover, heat exposure has been linked to AKI in other studies of otherwise healthy individuals such as athletes and military recruits.Given the high ambient temperatures in the Central Valley and the strenuous nature of agricultural work, our estimates of heat strain using the PSI were surprisingly lower than we expected, particularly among women, none of whom experienced heat strain. Other researchers have found agricultural work to be associated with high levels of heat strain both in the USA and in other countries.The Central Valley has low levels of humidity, which may allow workers to maintain cooler body temperatures than in other agricultural areas with high humidity. In addition, California is progressive in its prevention of heat related illness through regulations of the state Occupational Safety and Health Administration . Under Cal-OSHA requirements, farmers are required to provide heat illness prevention training for workers and offer regular breaks to cool off and rehydrate . Despite research that suggests workers do not remember the information provided in the trainings and do not take recommended breaks,443 our estimates of heat strain indicate that workers in our sample do not experience high levels of heat strain. This may be related to the different farm tasks performed, suggesting that not all farm work is strenuous. For example, the majority of the women were involved in packing or weeding, which is less strenuous than picking. However, the finding that heat strain in males was statistically associated with incident AKI suggests that agricultural workers who do experience high levels of heat strain are at risk of adverse renal effects.

Fortunately, current research into simple interventions, such as the use of backpack water reservoirs and the enforcement of rest periods during agricultural work, has had an effect on symptoms of heat strain and may provide a potential means of protecting the kidneys. The finding that women are affected differently by occupational exposures than men may be expected due to known gender differences in agricultural work. However, we were surprised to see that the occupational risk factors of years in agricultural work and payment method were associated with AKI in women in our sample. Studies of women’s experiences in agricultural work have documented the risk of sexual harassment or assault, which often occurs around bathroom facilities.Women may tend to limit drinking or eating during their work shift to reduce their need to use these facilities, or may delay trips to the bathroom during the work day out of fear for their safety. In a study of women in India who experienced heat stress at work, researchers found that delayed urination among women was associated with increased risk of urinary tract infection and AKI.The association of years of agricultural work and AKI among women in our sample could suggest that chronic delayed urination may increase the risk of AKI.Our finding that workers paid by the piece had higher odds of AKI requires further investigation, particularly because our sample size yielded imprecise estimates, and wide CIs may be attributed to the low numbers of women who experienced AKI and were paid by the piece . Piece rate work incentivises the worker to work harder and to take fewer breaks by financially rewarding higher productivity.Women who are paid by the piece may have an extra incentive to not visit the bathroom during the work shift, and piece rate work is associated with other poor health outcomes, including higher rates of accidents,musculoskeletal injury and risk-taking among workers.The independent association of piece rate work on AKI among women in our models suggests that piece rate work is a marker of conditions potentially damaging to kidney function, and that this mechanism is separate from heat strain or hydration status. Alternatively, piece rate work may be a better measure of the factors suspected to be involved in the development of AKI, which could explain the associations found here. In either case, modifications to the pay structure may help prevent AKI in agricultural workers. While not a risk factor for AKI in our estimations, the majority of workers in our sample experienced volume depletion after an agricultural work shift as measured by change in body mass. Other estimates of fluid intake among agricultural workers suggest that the amount of water workers drink is not sufficient to replace fluids and electrolytes lost during the work shift,as many do not believe they are at risk for injury and do not adequately rehydrate.