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Open Access Publications from the University of California


California Agriculture is a quarterly peer-reviewed journal reporting research, reviews and news on California’s agricultural, natural and human resources.

Volume 72, Issue 2, 2018

Issue cover
Cover Caption:A romaine lettuce harvester. Photo courtesy of Taylor Farms.

Research and Review Articles

Employment and earnings of California farmworkers in 2015

The average employment of hired workers in California agriculture (NAICS 11) rose over 10% between 2005 and 2015, when some 16,400 agricultural establishments hired an average 421,300 workers who were paid a total of $12.8 billion, which was 27% of the state's $47 billion in farm sales. This means that a full-time equivalent (FTE) employee would earn $30,300, implying an hourly wage of $14.55 for 2,080 hours of work. We extracted all Social Security numbers reported by California agricultural establishments and found that the average annual pay received by the 848,000 workers who had at least one job on California farms was $20,500 in 2015, two-thirds of the average annual wage of an FTE worker, reflecting some combination of lower wages and less than full-year work.

Automated lettuce thinners reduce labor requirements and increase speed of thinning

Salinas Valley lettuce growers are adopting automated lettuce thinners to improve labor efficiency. We conducted field studies in 2014 and 2015 to compare the time involved in automated and manual thinning of direct-seeded lettuce and any differences in lettuce quality and yield. We recorded the number of doubles (two closely spaced plants) left behind after thinning, time taken to remove the doubles, final crop stand, efficiency in weed removal, crop yield and disease incidence. Using an automated thinner in place of manual hoeing reduced the thinning labor requirement from 7.31 ± 0.5 person-hours per acre to 2.03 ± 0.5 person-hours per acre. Automated thinning left more doubles than manual thinning, resulting in additional time to remove them, but was overall more labor-efficient and had no impact on yield or disease incidence.

Wild pigs breach farm fence through harvest time in southern San Joaquin Valley

Wild pigs cause around $1 billion of damage to agriculture in the United States each year — foraging on crops, breaking branches and vines, and damaging irrigation lines and fences — but little is known about how and when they access agricultural fields. We used wildlife camera traps to document and describe wild pig access to two fenced southern San Joaquin Valley farms. Pigs breached fences around agricultural fields, especially during the harvest period when crops were ripe, and almost exclusively at night, outside of the regulated, daytime recreational pig hunting period. GPS data from an adult boar revealed that pigs may travel long distances from wildlands to reach crops. The results of our case study suggest that increasing monitoring and maintenance of fences during the harvest season and removing pigs that have learned to access farms may help reduce pig damage to agricultural fields. The results also suggest a formal scientific investigation of risk factors and strategies to reduce wild pig damage is warranted.

Central Coast growers' trust in water quality regulatory process needs rebuilding

Growing evidence of agricultural water pollution in California's Central Coast even after the implementation of tough water quality regulations has increased the pressure on regional stakeholders. Previous research has shown that collaborative relationships between growers and regulators can motivate growers to make management decisions that benefit the environment. However, informal evidence suggested trust might have been eroding between growers and the Central Coast Regional Water Quality Control Board (CCRWQCB, the regulator) since 2004, the year the first legislation went into effect. Using a survey conducted in 2015, interviews and in-depth document review, this study assesses growers' trust of and communication with other agricultural groups and water quality regulatory agencies, specifically CCRWQCB. Survey results were compared to results of the same survey sent out in 2006. Results corroborate other research — growers' trust of most regional agricultural groups was closely correlated with frequency of communication. However, growers' trust of CCRWQCB did not correspond to the relatively high contact frequency and had declined since 2006. The literature on rebuilding trust suggests ways forward for CCRWQCB.

Teens-as-teachers nutrition program increases interest in science among schoolchildren and fosters self-efficacy in teens

The Healthy Living Ambassador Program brings health, teen leadership, and teamwork to California's elementary school gardens through interdisciplinary UC Cooperative Extension collaboration, community-based partnerships and teen teaching. During spring 2015, teen ambassadors trained by Extension educators and volunteers at UC Elkus Ranch in San Mateo County taught nutrition science, food cultivation and healthy living skills in an 8-week, garden-based, after-school nutrition and physical education program for elementary school children in an urban setting. We conducted a pilot study using a mixed-methods approach to measure and explore the program's impact on children's vegetable selection and consumption preferences, as well as perceived self-efficacy in teen healthy living behavior. The children trended toward an increased preference for gardening, cooking and science, and teens displayed an increase in perceived health self-efficacy.

News and Opinion

The race in the fields: Imports, machines and migrants

Four ways farmers are responding to the tightening labor market.

Next-generation mechanization

New advances in image-recognition technology and robotics are reducing the need for manual labor — and potentially herbicides as well.

Research highlights

Briefs of recent AES and UCCE research papers on tree mortality, sugary drinks, mountain runoff and wild bees.