California Agriculture Research Articles

Erratum to: Antibiotic Resistance in Airborne Bacteria Near Conventional and Organic Beef Cattle Farms in California, USA

Erratum to: Antibiotic Resistance in Airborne Bacteria Near Conventional and Organic Beef Cattle Farms in California, USA

Fresh-cow handling practices and methods for identification of health disorders on 45 dairy farms in California.

The aim of the present study was to describe fresh-cow handling practices and techniques used during fresh cow evaluations to identify postpartum health disorders on 45 dairy farms in California ranging from 450 to 9,500 cows. Fresh cow practices were surveyed regarding (a) grouping and housing, (b) scheduling and work organization, (c) screening for health disorders, and (d) physical examination methods. Information was collected based on cow-side observations and responses from fresh cow evaluators. Cows were housed in the fresh cow pen for 3 to 14 (20%), 15 to 30 (49%), or >31 (31%) d in milk. Fresh cow evaluations were performed daily (78%), 6 times a week (11%), 2 to 5 times a week (9%), or were not routinely performed (2%). There was significant correlation between the duration of fresh cow evaluations and the number of cows housed in the fresh pen. Across all farms, the duration of evaluations ranged from 5 to 240 min, with an average of 16 s spent per cow. During fresh cow checks, evaluators always looked for abnormal vaginal discharge, retained fetal membranes, and down cows. Dairies evaluated appetite based on rumen fill (11%), reduction of feed in the feed bunk (20%), rumination sensors (2%), or a combination of these (29%). Milk yield was evaluated based on udder fill at fresh cow checks (40%), milk flow during milking (11%), milk yield records collected by milk meters (2%), or a combination of udder fill and milk meters (5%). Depressed attitude was evaluated on 64% of the dairies. Health-monitoring exams for early detection of metritis were implemented on 42% of the dairies based on rectal examination (13%), rectal temperature (22%), or both (7%). Dairies implementing health-monitoring exams took longer to perform fresh cow evaluations. Physical examination methods such as rectal examination, auscultation, rectal temperature evaluation, and cow-side ketosis tests were used on 76, 67, 38, and 9% of dairies, respectively. Across dairies, we found large variation in signs of health disorders screened and how those signs were evaluated. Fresh cows were primarily evaluated based on nonspecific and subjective observations during screening. Future research efforts should focus on developing and validating scoring systems to more objectively identify health disorders in postpartum cows.

Factors affecting the numbers of expected viable lactic acid bacteria in inoculant applicator tanks.

The application of correct numbers of viable microorganisms to forages at the time of ensiling is one of the most important factors affecting the probability of a beneficial effect from an inoculant. The objective of this study was to determine relationships between numbers of expected lactic acid bacteria (LAB) from silage inoculants in application tanks and various factors that might affect their viability. The pH and temperature of inoculant-water mixes were measured in applicator tanks (n=53) on farms in Wisconsin, Minnesota, South Dakota, and California during the corn harvest season of 2012. Samples were collected on-farm and plated on de Man, Rogosa, and Sharpe agar to enumerate LAB and establish the number of viable LAB (cfu/mL). Expected numbers of LAB were calculated from the minimum label guarantees for viable bacteria and mixing rates with water. In addition, the pH of the inoculant-water mixes at sampling, the ambient temperature at sampling, and the length of time that the samples had been in the tank were measured and obtained. The log difference between the measured and expected numbers of LAB was calculated and expressed as ΔM - E in log scale. Ambient temperature at sampling had no relationship with time in the tank or ΔM - E. Most (83%) of the inoculants had been mixed with water in the applicator tanks for <10h. For these samples, a negative linear correlation (R2=0.36) existed between time that the inoculant-water mixes were in the applicators tanks and ΔM - E. The pH of the inoculant-water mixes was also negatively correlated (R2=0.28) with time in the applicator tank, but pH was not related to ΔM - E. The temperatures of the inoculant-water mixtures were negatively correlated with ΔM - E (R2=0.39). Seven of 8 samples whose ΔM - E were at least -0.95 or more lower than expected (equivalent of about 1 or more log concentration less than expected) had water temperatures above 35°C. These data support our previous laboratory findings and suggest that high temperatures of inoculant-water mixes have the potential to negatively affect the final application rate of some inoculants, which may affect their overall effectiveness to improve silage fermentation.

Identifying Food Safety Barriers among Small and Mid-Sized California Farmers

Identifying Food Safety Barriers among Small and Mid-Sized California Farmers

How many workers are employed in California agriculture?

In 2014, the average employment of hired workers in California crop and livestock agriculture, counting all occupations, rose by 10% to 410,900. However, although the state reports the number of jobs on farms regularly, it does not report the number of workers who fill these jobs. We analyzed all Social Security numbers reported by farm employers in 2014 and found two workers for each average or year-round equivalent farm job, making the total number of farmworkers employed in agriculture 829,300, or twice average employment. Approximately 83% of farmworkers had their maximum earnings with an agricultural employer in 2014, and almost 80% of those primary farmworkers were employed by crop support firms (392,000) or fruit and nut farms (154,000). Over 60% of all workers had only one farm employer, followed by 27% with two or more farm employers, and 35% were employed in Kern (116,000), Fresno (96,000) and Monterey (82,000) counties. These data show that California has a remarkably stable farm workforce: most farmworkers are attached to one farm employer, often a labor contractor who moves them from farm to farm.

Berry research at Hansen Agricultural REC helps growers increase yields

News from the RECs At Hansen Agricultural REC, better blackberries and a soil disinfestation alternative Hazel White A t 27 acres, Hansen Agricultural Research and Extension Center (HAREC), in Ventura County, is small. It is exposed to the Santa Ana winds and has heavy clay loam soil infested with one of the highest levels of Verticillium wilt fungus recorded anywhere in the state. And yet it’s proving a major resource for Central Coast growers interested in producing a very profitable blackberry crop or in managing soil pests in strawberries without fumigation. HAREC has developed a growing program for a firm, sweet, large blackberry to produce a good yield during a high-prices sales window in late summer and fall. UC Cooperative Extension (UCCE) Farm Advisor Oleg Daugovish, in charge of berry research, is also contributing to the in- ternational knowledge bank on anaerobic soil disinfestation (ASD), an alternative to chemical fu- migation that uses waste carbon products, such as rice bran. Growers of high-value organic strawber- ries in the Central Coast region have taken up ASD enthusiastically. Prime-Ark 45 blackberry In fall 2011, a new, publicly available primocane blackberry variety, Prime-Ark 45, from the Uni- versity of Arkansas fruit breeding program was planted at HAREC. “It looked good, tasted good, and yielded well,” Daugovish recalls. Since then he has established how to manipulate the timing of the harvest, working with UCCE researchers with blackberry trials under way in other parts of the coast: Mark Bolda, UCCE Director and Farm Advisor in Santa Cruz County, and Mark Gaskell, UC Small Farms Program Advisor in San Luis Obispo and Santa Barbara counties (Gaskell and Daugovish 2016). “Our results are consistent and add up to the same story,” says Daugovish. “This is a high-quality crop, easy to manage, and fruiting can be optimized for the lucrative window in late summer.” Oleg Daugovish Timing the California blackberry harvest for late summer, when berries from other sources are scarce, helps growers maximize returns. 104 CALIFORNIA AGRICULTURE • VOLUME 70 , NUMBER 3

Antibiotic Resistance in Airborne Bacteria Near Conventional and Organic Beef Cattle Farms in California, USA

Levels of antibiotic resistance genes (ARGs) and the fractions of antibiotic resistant bacteria (ARB) among culturable heterotrophic bacteria were compared in outdoor air near conventional (n = 3) and organic (n = 3) cattle rearing facilities. DNA extracts from filters taken from 18 locations were analyzed by quantitative polymerase chain reaction (qPCR) for five ARGs. At the reference (non-agricultural) site, all genes were below detection. ARGs sul1, bla SHV, erm(B), and bla TEM were more frequently detected and at higher levels (up to 870 copies m−3 for bla SHV and 750 copies m−3 for sul1) near conventional farms compared to organic locations while the opposite was observed for erm(F) (up to 210 copies m−3). Isolates of airborne heterotrophic bacteria (n = 1295) collected from the sites were tested for growth in the presence of six antibiotics. By disk diffusion on a subset of isolates, the fractions of ARB were higher for conventional sites compared to organic farms for penicillin (0.9 versus 0.63), cloxacillin (0.74 versus 0.23), cefoperazone (0.58 versus 0.14), and sulfamethazine (0.50 versus 0.33) for isolates on nutrient agar. All isolates’ ΔA600pres/ΔA600abs were measured for each of the six tested antibiotics; isolates from farms downwind of organic sites had a lower average ΔA600pres/ΔA600abs for most antibiotics. In general, all three analyses used to indicate microbial resistance to antibiotics showed increases in air samples nearby conventional versus organic cattle rearing facilities. Regular surveillance of airborne ARB and ARGs near conventional and organic beef cattle farms is suggested.

ADAPTATION IN CALIFORNIA AGRICULTURE: WHAT HAVE WE BEEN ASSESSING FOR TWO AND A HALF DECADES?

Following the release of the IPCC Fifth Assessment Report, and realizing the likely impact on California water and agricultural sectors, we review key concepts in the climate change lexicon in the context of California agriculture. There are a range of modeling approaches used to study the benefits of water basin- and/or farm-level adaptations, including hydrological, crop simulation, economic programming, and econometric models. Given the central role of farmer and institutional responsiveness, how do recent agro-economic assessments suggest that specific adaptations may improve economic welfare and reduce vulnerability? What is economically efficient adaptation in the short and long-run? What are the limits to the agricultural sector’s adaptive capacity?

Evaluation of two methodologies for lameness detection in dairy cows based on postural and gait abnormalities observed during milking and while restrained at headlock stanchions

Lameness is a critical issue on dairies with an impact on production and animal welfare. Early lameness detection followed by effective treatments could improve prognosis and cure rate of lame cows. Current methods for lameness detection are based on locomotion score (LS) that requires observation of cows walking, preferably at the exit of the milking parlor. This is a time-consuming task that is difficult to implement on large dairies. Therefore, a common methodology for lameness detection is based on milkers’ and cow pushers’ observations of cows walking to the milking parlor or standing at the milking stall (MPP). Observation of postural abnormalities predictive of lameness while cows are locked at stanchions (S) can be used as an alternative detection method. The objective of this research was to study the association between postural and gait abnormalities observed with S and MPP methodologies and lameness using LS≥3 as the reference method, as well as to evaluate the epidemiological characteristics of those methods as a diagnostic test for lameness. A secondary objective was to describe the type of hoof lesions observed with postural and gait abnormalities detected with LS, MPP, and S methodologies. A cross-sectional study design was performed on 2274 cows from one farm in California (US). Arched back, cow-hocked, wide-stance, and favored-limb postures as well as uneven gait were observed. Both lameness detection methodologies, S and MPP, indicated that arched back and favored-limb were postural abnormalities associated with lameness. However, the epidemiological test characteristics for each of the postures evaluated as a diagnostic test for lameness indicated that both detection methods, S and MPP, had good specificity (>0.91) but poor sensitivity (0.04–0.39). A convenience sample of 104 cows, selected based on LS>3, favored-limb, presence of two or more abnormal postures, and gait anomalies with either S or MPP methods, received a hoof examination. Lesions were observed on cows selected by LS (17/24), MPP (21/30), and S (33/60) criteria, suggesting a lack of concordance between lameness detection methodologies and visible hoof lesions. Nevertheless, due to the lack of acceptance of LS as the lameness detection method on large commercial dairies in California, it is imperative that future research evaluates modifications of S and MPP lameness detection techniques, considering hoof lesion as reference method.

Conservation agriculture: Systems thinking for sustainable farming

Outlook Conservation agriculture: Systems thinking for sustainable farming by Jeffrey Mitchell, Ron Harben, Garrison Sposito, Anil Shrestha, Daniel Munk, Gene Miyao, Randy Southard, Howard Ferris, William R. Horwath, Eric Kueneman, Judee Fisher, Monte Bottens, Phil Hogan, Robert Roy, Jim Komar, Dwayne Beck, Don Reicosky, Michelle Leinfelder-Miles, Brenna Aegerter, Johan Six, Tom Barcellos, Dino Giacomazzi, Alan Sano, Jesse Sanchez, Mike Crowell, John Diener, Darrell Cordova, Trevor Cordova and Jerry Rossiter C alifornia is an unquestioned global leader in the productivity of its farms and the diversity and quality of its crops. However, there are significant threats to the sustainability of the state’s agricultural systems. The scarcity of water has received great attention in recent years, but that is just one of many concerns. Fossil fuel use, carbon emissions, nitrate pollution of groundwater, labor cost and availability, air pollution and loss of soil fertility all present challenges to the long-term viability of farming in California. Conservation agriculture can help to address all of these issues. Fundamentally, conservation agriculture is about “kindly use” of the land, to quote farmer-essayist Wendell Berry. It is based on three principles: reducing soil disturbance (tilling less, or not at all), retaining crop residues on the soil surface year-round and fostering crop and soil biodiversity. By designing farming systems around these principles, our work has shown that farmers can save water, store more carbon in the soil, burn less fossil fuel, cut labor costs, lower dust emissions and increase profits. Despite conservation agriculture’s promise, how- ever, its adoption has been slow in California. In the Midwest and Great Plains regions, conservation ag- riculture is practiced on more than 30% of cropland, • Water: No-till, surface mulching practices and in- creases in soil organic matter can reduce soil wa- ter evaporation by 4 to 5 inches annually (Klocke et al. 2009; Mitchell, Singh et al. 2012; van Donk et al. 2010) and increase soil water storage ca- pacity by the equivalent of roughly 2 inches (Franzluebbers 2010; Hudson 1994). If applied on a significant amount of California’s roughly 8.5 million acres of irrigated lands, these measures could reduce statewide irrigation demand by millions of acre-feet. • Cost: By limiting tractor passes and other opera- tions, reduced-tillage practices cut production costs by $100 to $150 per acre across a range of crops grown in California (Mitchell, Carter et al. 2012; Mitchell, Klonsky et al. 2012). http://californiaagriculture.ucanr.edu • APRIL–JUNE 2016 53 Ron Harben In 2010, CASI held a public education event on cover crops for farmers and private sector, UC and NRCS participants at the UC ANR West Side Research and Extension Center in Five Points. compared with less than 5% of annual cropland in California. As founders and members of the Conservation Agriculture Sustainability Innovation center (CASI), we are partnering with California farmers and equipment makers to develop conser- vation agriculture practices and technologies that are effective and appropriate for the state’s produc- tion systems, and to build networks to help their adoption. The magnitude of the benefits possible with con- servation agriculture is striking. A few examples:

Public funding for agricultural research benefits us all

Editorial Public funding for agricultural research benefits us all by Glenda Humiston, Vice President, UC Agriculture and Natural Resources I n February, President Obama proposed a budget for fiscal year 2017 that would double funding, to $700 million, for the Agriculture and Food Research Initiative (AFRI), the nation’s premier competitive grant program for research in the agricultural sciences. Glenda Humiston benefit of $33 per additional public dollar invested in agricultural research here. There are countless concrete examples of how agri- culture in California is benefiting from publicly sup- ported research today. UC ANR Cooperative Extension research and out- reach has been instrumental in the development of I applaud this proposal. In recent decades, fed- drip irrigation, which is now used on approximately eral support for agricultural research has waned, 40% of irrigated cropland in California. A recent study even as key international competitors like Brazil and valued the benefit attributable to this research at be- China have increased their investments in this area tween $78 million and $283 million per year. dramatically. Publicly supported research is critical to the ongo- Agricultural research helps farmers compete in the ing management of invasive pests and diseases. One global market and meet food demand, and it is critical major current focus in California is huanglongbing to the continued growth of U.S. agricultural (HLB) disease. Spread by the Asian citrus psyllid, HLB productivity. It also addresses a host of has damaged 100,000 acres of Florida citrus since 2007. other issues: climate change, safe drinking In California, it has been found in residential citrus water, childhood obesity, the ecosystem trees but not yet in commercial orchards. In February, services provided by farmland, the invasive USDA awarded $20.1 million for research nationwide species that damage crops and spread dis- to fight the disease, including nearly $4 million to UC eases, and many more. Riverside, where researchers are working to develop Public support for research in these areas early detection methods and HLB-resistant rootstocks is essential and irreplaceable, and the avail- to help protect California’s $2.1 billion citrus industry. ability of competitive grant funding helps With California’s aquifers stressed after years to attract top young scientific talent to study of drought and subject to new rules for sustainable the full range of agricultural problems. management, UC ANR researchers are testing the use Private sector funding for agricultural of farm fields and orchards as percolation basins. It’s research also contributes to innovation a new approach to recharge depleted groundwater and progress — and now exceeds USDA research basins by capturing flows from rivers in winter, when spending. But business concerns tend to focus those water is often abundant. research dollars on a few large crops, mainly corn and This issue of California Agriculture illustrates the soybeans, and on applications likely to yield a near- range of issues that researchers are tackling — from term profit. sustainable water reuse for irrigation to managing That leaves a great deal of important pests with fewer pesticides to promoting nutrition and work reliant on public support — community gardens. These represent just a sample of particularly in California, with the ways that agricultural research continues to our extraordinarily diverse agri- contribute to the health, prosperity and security cultural sector. of California and the nation. c Agricultural re- search is also an excel- lent investment for our economy. One in 12 jobs in America is invested in linked to agriculture. agricultural Nationally, every ad- ditional dollar invested research in USDA research returns a benefit of roughly $20. In California, the gains in benefit to California are even greater, with an estimated 52 CALIFORNIA AGRICULTURE • VOLUME 70 , NUMBER 2

Cumulative Incidence of Acute Kidney Injury in California's Agricultural Workers.

Chronic kidney disease in Central America suggests that agricultural work is potentially harmful to the kidneys. We investigated the cumulative incidence of acute kidney injury (AKI) over one work shift among agricultural workers in California. Serum creatinine was measured both before and after a work shift to estimate AKI. Associations of incident AKI with traditional and occupational risk factors were tested using Chi-square and trend tests and logistic regression. In 295 agricultural workers, AKI after a summer work shift was detected in 35 participants (11.8%). Piece-rate work was associated with 4.52 adjusted odds of AKI (95% confidence interval 1.61 to 12.70). The cumulative incidence of AKI after a single day of summer agricultural work is alarming due to an increased risk of long-term kidney damage and mortality.

Associations Between Plasma Fatty Acid Composition, Estimated Desaturase Indices, and Measures of Insulin Resistance in 4th‐ and 5th‐grade Children

Lipidomics is often used to characterize the role of lipids in disease; however, few reports document lipid profiles of children. The aim of this study was to evaluate plasma fatty acid profiles in children and identify potential correlates with markers of metabolic health. The fatty acid profiles of children (n=85, ages 9–12) were determined. Anthropometric data, dietary intake data, and plasma were collected. Fasting plasma was analyzed for total fatty acids, glucose, insulin, and full lipid panels for this cross‐sectional study. Insulin resistance was estimated using calculated HOMA‐IR values. Pearson's correlation was used to exam the relationship between HOMA‐IR and blood biomarkers, analysis of covariance was used to determine differences between groups, and multivariate regression was used to determine the predictors of HOMA‐IR. An increased proportion of palmitic acid (16:0) often characterizes insulin resistant states. A negative correlation between HOMA‐IR values and 18:0/16:0 ratio (r=−0.37, P=0.005) was observed. When analyzed by HOMA‐IR quartiles, the highest quartile had a mean difference of −0.05 in the 18:0/16:0 ratio compared to the lowest quartile (P=0.030). A high stearoyl‐CoA‐desaturase (SCD) index, estimated by taking the ratio of 16:1n7/16:0, has been linked to obesity and metabolic syndrome and in this study HOMA‐IR correlated with SCD‐16 (r=0.35, P=0.001). Mean SCD index was greater among the third and fourth quartiles of HOMA‐IR compared to the first (P=0.020). A low Delta‐5‐Desaturase (Δ5D) is often associated with lower risk for metabolic diseases and mean Δ5D was highest in the fourth quartile of HOMA‐IR (P=0.02). In the linear regression model, BMI, 16:0 ratio, and Δ5D were the strongest predictors of HOMA‐IR (r2=0.38, P=0.01). Consistent with adult studies, insulin resistance in children appears to be associated with increased 16:0 proportions and SCD activity indices in plasma. Though these children appear healthy, the type and level of lipidomic markers may be indicative of the degree of insulin resistance. Evaluating plasma fatty acid profiles of children may help establish early disease risk.Support or Funding InformationFunding provided by University of California Agriculture and Natural Resources Competitive Grant #11‐1018, USDA Training Grant 2011‐38420‐20082, USDA NIFA, Hatch project 221082, USDA Intramural Project 2032‐52530‐022‐00D, and NIH 1U24DK097154‐01. The USDA is an equal opportunity provider and employer.

Understanding organic potato fertilization dynamics at Intermountain REC

News from the RECs Understanding organic potato fertilization dynamics at Intermountain REC S trong consumer demand and high prices are encouraging an increasing number of potato growers to consider organic production. Growing organic potatoes introduces new complexities for nutrient and pest management — complexities that Intermountain Research and Extension Center (IREC) Director Rob Wilson and Daniel Geisseler, a UC ANR Cooperative Extension specialist based at UC Davis, are unraveling in an ongoing experiment. Rob Wilson Researchers at IREC are evaluating different organic amendment and cover crop treatments for organic potato production. IREC, in the Siskiyou County town of Tulelake, serves the Klamath Basin farming region, an area of roughly 200,000 acres of irrigated land on the California-Oregon border that is one of the leading potato-growing regions for both states. At an eleva- tion of roughly 4,000 feet and with a high desert climate, farming conditions in the basin are quite dif- ferent from the Central Valley and other low-elevation agricultural regions of California. Potatoes have a relatively high demand for nitro- gen, and organic growers have two general ways to provide it: organic amendments like manure, compost and blood meal; or nitrogen-fixing cover crops, such as varieties of vetch or field peas. Wilson and Geisseler are teasing out the costs and benefits of the various options and developing 60 CALIFORNIA AGRICULTURE • VOLUME 70 , NUMBER 2 nutrient-monitoring plans to guide growers’ man- agement decisions. While the work is tailored to the needs of potato growers in the Klamath Basin, it will also help to expand the understanding of nutrient dy- namics in organic farming systems more broadly. In organic farming systems, meeting a crop’s nitro- gen need is complicated because the available sources, whether cover crops or amendments, provide nitrogen in a form — organic nitrogen — that is not directly available to plants. By contrast, the fertilizers used on conventional farms generally provide nitrogen in plant-available forms — ammonia and nitrate — known as mineral forms of nitrogen. Soil microbes convert organic nitrogen to ammonia and then to nitrate. Mineralization takes time, and it happens at a different rate depending on the source — the nitrogen in chicken manure is mineralized more quickly than that in steer manure, for instance. The rate is also influenced by environmental variables such as soil type and temperature. The mineralization timetable is important because potatoes need a signifi- cant amount of nitrogen in the early stages of their life cycle, before the potato tubers start to grow in earnest. One objective of the research project is to evaluate how the nitrogen mineralization process proceeds for cover crop residues. Around 90% of the nitrogen in a nitrogen-fixing cover crop is contained in the above- ground plant tissue. To convert that nitrogen into a

Cantaloupe melon ( Cucumis melo L.) conservation using hydrocooling

ABSTRACT Maintaining cantaloupe melon at field temperature impairs conservation as it speeds up cell metabolism and transpiration, and, consequently, reduces shelf life. This study aimed to evaluate the conservation of Torreon hybrid cantaloupe using the hydrocooling treatment. Fruits were harvested at the commercial maturity stage (60 days after planting), in the morning, at the Nova California Farm, municipality of Mossoró-RN, in September 2007. One set of fruit was immersed in chilled water at 5 ºC for 5 min, at the packing house, while the remaining set was not hydro cooled. Then, both sets (treated and untreated with hydrocooling) were pre-cooled in air forced tunnels at 7 ºC, until the temperature in the pulp reached 10 ºC. Both fruit sets were stored for 0, 14, 21, 28 and 35 days under modified atmosphere at 3 ± 1 oC and 90 ± 5% RH. After each storage period, the fruits were incubated in an atmosphere-controlled chamber at 20 ± 2 oC and 80 ± 5% de RH, for seven days. The following characteristics were evaluated: external and internal appearance, mass loss, soluble solids, firmness and titrable acidity. The experiment was arranged in a completely randomized split-plot design with four replications of three fruits. The plots consisted of the hydrocooling conditions (with and without fruit soaking in chilled water), and the sub-plots consisted of the storage times (0, 14, 21, 28 and 35 days).The treatment with hydrocooling was efficient in keeping the firmness and soluble solids of the fruits and shortened the pre-cooling time in the cooling tunnel. However, hydrocooling did not increase fruit shelf-life.

Precision overhead irrigation is suitable for several Central Valley crops

Overhead systems are the dominant irrigation technology in many parts of the world, but they are not widely used in California even though they have higher water application efficiency than furrow irrigation systems and lower labor requirements than drip systems. With water and labor perennial concerns in California, the suitability of overhead systems merits consideration. From 2008 through 2013, in studies near Five Points, California, we evaluated overhead irrigation for wheat, corn, cotton, tomato, onion and broccoli as an alternative to furrow and drip irrigation. With the exception of tomato, equal or increased yields were achieved with overhead irrigation. Many variables are involved in the choice of an irrigation system, but our results suggest that, with more research to support best management practices, overhead irrigation may be useful to a wider set of California farmers than currently use it.

After the Incubator: Factors Impeding Land Access Along the Path from Farmworker to Proprietor

Farmworkers aiming to transition to independent proprietorship often benefit from beginning farmer incubator programs that offer agricultural training, subsidized farmland rents, and marketing and business assistance. Incubator initiatives often align with various efforts to stem the tide of shrinking U.S. farm numbers and enhance the viability of small-scale, environmentally and socially regenerative enterprises. Yet even as these promising initiatives provide former farmworkers with initial tools for success, structural barriers can impede beginning farmers' eventual transition to independent proprietorship. Land access is one well-known barrier to entry. Impediments to land access for beginning farmers are frequently framed purely in terms of available acreage and/or sufficient start-up capital. Sociocultural and relational factors mediating land access are less well understood. Our study addresses this gap, examining how sociocultural and relational constraints impede land access for former immigrant farmworkers aspiring to independent farming in California's Central Coast region. We employ qualitative methods, including 26 in-depth interviews, focus groups, and participant observation, to explore barriers to land access faced by aspiring small-scale organic farmers participating in an established regional organic farm incubator program. Our findings indicate that these beginning farmers are highly motivated, possess sophisticated farming skills, and wish to shape their livelihoods independently. However, their access to farmland is mediated by landowner and tenant farmer relationships, including lease arrangements, and sociocultural barriers, including ethnicity and/or cultural identity. In a context in which incubator initiatives are envisioned as means to facilitate new entry of former immigrant farmworkers into the agricultural sector, this case study analysis traces specific sociocultural contours associated with land access that impede successful proprietorship for beginning farmers. We conclude by suggesting potential strategies for addressing these barriers to entry in order to facilitate enhanced efficacy of incubator programs. See the press release for this article.&nbsp

Labor strategies and agribusiness counterstrike during the Bracero Era: the peculiar case of the National Farm Labor Union, 1946–1952

This article investigates the responses of the political establishment and the agro-industry to the militant actions of the National Farm Labor Union (NFLU) from 1946 until 1952. It confirms the well-known hypothesis that the maintenance of the bracero program affected the efforts to form agricultural unions in California, but it also underlines strategies and the roles played by the agro-industry, California Farm Placement Service and other federal instances of government in the weakening of agricultural unionization. It argues that the agricultural unions’ weakness in California throughout this period can be attributed to the needs of the food-processing industry and the latter’s special relationship with the political establishment. I demonstrate that while the failure to consolidate agricultural unions in California during the postwar years, is not attributable to the strategies adopted by the NFLU per se, it is closely related to a lack of support from the major political players and to the privileged relationship they built up with Mexican officials. The influence of some public servants, political representatives and agribusiness lobbyists has been crucial for the continuation of the bracero program and has also obstructed the NFLU to organize efficiently strikes and boycotts.

Carbon Abatement and Emissions Associated with the Gasification of Walnut Shells for Bioenergy and Biochar Production.

By converting biomass residue to biochar, we could generate power cleanly and sequester carbon resulting in overall greenhouse gas emissions (GHG) savings when compared to typical fossil fuel usage and waste disposal. We estimated the carbon dioxide (CO2) abatements and emissions associated to the concurrent production of bioenergy and biochar through biomass gasification in an organic walnut farm and processing facility in California, USA. We accounted for (i) avoided-CO2 emissions from displaced grid electricity by bioenergy; (ii) CO2 emissions from farm machinery used for soil amendment of biochar; (iii) CO2 sequestered in the soil through stable biochar-C; and (iv) direct CO2 and nitrous oxide (N2O) emissions from soil. The objective of these assessments was to pinpoint where the largest C offsets can be expected in the bioenergy-biochar chain. We found that energy production from gasification resulted in 91.8% of total C offsets, followed by stable biochar-C (8.2% of total C sinks), offsetting a total of 107.7 kg CO2-C eq Mg-1 feedstock. At the field scale, we monitored gas fluxes from soils for 29 months (180 individual observations) following field management and precipitation events in addition to weekly measurements within three growing seasons and two tree dormancy periods. We compared four treatments: control, biochar, compost, and biochar combined with compost. Biochar alone or in combination with compost did not alter total N2O and CO2 emissions from soils, indicating that under the conditions of this study, biochar-prompted C offsets may not be expected from the mitigation of direct soil GHG emissions. However, this study revealed a case where a large environmental benefit was given by the waste-to-bioenergy treatment, addressing farm level challenges such as waste management, renewable energy generation, and C sequestration.

Incidence, Severity, and Welfare Implications of Lesions Observed Postmortem in Laying Hens from Commercial Noncage Farms in California and Iowa.

The egg industry is moving away from the use of conventional cages to enriched cage and noncage laying hen housing systems because of animal welfare concerns. In this study, the prevalence and severity of lesions in noncage laying hens from commercial farms in two of the largest egg-producing states, California and Iowa, were evaluated by postmortem examination. Hens that died or were culled were collected during early, mid, and late stages of the laying cycle from 16 houses on three farms. Of the 25 gross lesions identified for study, 22 were observed, with an average of four lesions per hen. Vent cannibalism, reduced feather cover, keel bone deformation, and beak abnormalities were the most frequent lesions, observed in ≥40% of hens. Other common lesions were cloacal prolapse (30.5%), footpad dermatitis (24.3%), and septicemia (23.1%). Beak abnormality and enteric disease had the highest proportion of severe lesions. Pearson chi-square analysis revealed a number of stage-of-lay effects (P ≤ 0.05), some of which differed by state. For both states combined, the lesions observed more frequently during early lay were beak abnormalities, northern fowl mite infestation, and cage layer fatigue, whereas during mid lay, they were poor feather cover, vent cannibalism, footpad dermatitis, keel bone deformation, respiratory disease and roundworms. Feather pecking and cloacal prolapse were most common during late lay. Although differences in hen genetics, farm management practices, and environmental factors could all have affected the results of this study, the information provides a better understanding of hen health in noncage housing systems and could help to identify potential interventions to reduce hen welfare problems.