- Author: Pamela Kan-Rice
- Author: Jim Downing
2016 is the final year for the soil fumigant to be used in California crop fields.
For many years, California growers relied on methyl bromide to kill a wide range of soil-borne pests, from fungi to insects to weeds, before planting crops. 2016 marks the last year in which the highly effective soil fumigant will be available.
The University of California's peer-reviewed journal California Agriculture examines the impact of the methyl bromide phaseout on strawberries, California's third most valuable crop, behind only almonds and grapes, with annual farmgate sales of $2.5 billion.
First identified as an ozone-depleting compound in 1991, methyl bromide was scheduled for phaseout in the United States by 2005 under the Montreal Protocol, an international agreement to protect the stratospheric ozone layer.
While methyl bromide was used for many crops, California strawberry growers found it irreplaceable, which helped the industry win exemptions that have allowed a significant, though declining, quantity of the chemical to be used through 2016. Despite years of research into alternatives, no equally effective replacement has emerged.
Berry industry grows dramatically
In the first research article, UC Cooperative Extension advisors Laura Tourte and Mark Bolda and Karen Klonsky, emeritus UC Cooperative Extension economics specialist, review economic data on the berry sector — blackberries and raspberries as well as strawberries — in Santa Cruz and Monterey counties. They look ahead to factors, including water, consumer demands, labor, invasive pests, and the full phaseout of methyl bromide, that are likely to shape future growth.
Methyl iodide controversy
In a paper chronicling events leading up to the 2012 withdrawal of methyl iodide, once promoted as a viable methyl bromide substitute, Julie Guthman, UC Santa Cruz professor in the Department of Social Sciences, reports survey findings that point to a variety of reasons why strawberry growers did not move quickly to adopt the chemical after it was approved by state regulators. Concerns about public opposition topped the list, followed by a variety of other factors, including concern about methyl iodide's toxicity, and a lack of strong incentive to switch to the new chemical because of the availability of other fumigants, including methyl bromide.
Managing soilborne pests
Three articles look at new approaches to managing soilborne pests without methyl bromide.
“It now seems likely that no single measure will suffice to meet the challenge of soilborne pathogens,” write Margaret Lloyd, UC Cooperative Extension advisor, and Tom Gordon, UC Davis professor in the Department of Plant Pathology, in this issue's Outlook. “Rather, a multi-faceted approach will be required, one that integrates advances in disease resistance through breeding with closer attention to the factors that influence the survival, activity and spread of pathogen populations in soil.” They make the case for using a suite of strategies to manage soilborne pathogens — including collective action among growers to help limit the spread of pathogens between fields.
A news item on research at the UC ANR Hansen Agricultural Research and Extension Center covers ongoing research on anaerobic soil disinfestation, a chemical-free technique that is being used in a growing number of commercial fields. Project scientist Amanda Hodson and UC Davis professor Edwin Lewis, both in the Department of Entomology and Nematology, review a variety of approaches to managing for soil health — in strawberries and other crops — as a pest suppression strategy.
Other soil fumigants
Fumigants other than methyl bromide, such as chloropicrin, remain widely used in California strawberry production. Rachael Goodhue, UC Davis professor in the Department of Agricultural and Resource Economics at UC Davis, examines how increasingly stringent buffer zone requirements for chloropicrin application have an uneven impact on growers, depending on their proximity to developed land. In another article, a group of UC Cooperative Extension and U.S. Department of Agriculture scientists report on the effectiveness of several fumigants at dosages lower than the maximum label rate.
Food safety and nutrient management on the farm
The issue also includes two research papers focused on general production practices for crops. One report discusses on-farm food safety practices based on a survey of produce growers. The researchers found that practices such as exclusion fencing and vegetation clearing, which may negatively impact wildlife, remain widespread despite a lack of clear evidence that they enhance food safety. Finally, Daniel Geisseler, UC Cooperative Extension specialist in the Department of Land, Air and Water Resources at UC Davis, and Gene Miyao, UC Cooperative Extension advisor, review the use of soil testing to guide the management of soil phosphorus and potassium in California cropping systems.
To read California Agriculture, a peer-reviewed journal of research in agricultural, human and natural resources published by UC Agriculture and Natural Resources, visit http://calag.ucanr.edu. For a free subscription, sign up on the website or write to calag@ucanr.edu.
View this story in Spanish:
¿Qué hará la industria de la fresa sin el bromuro de metilo? http://ucanr.edu/sites/Spanish/noticias/?uid=6887&ds=199. Video on UCANR Spanish YouTube: California Agriculture: el bromuro de metilo en cultivos de fresa https://www.youtube.com/watch?v=5D4FwLqjaLk.
- Author: Pamela Kan-Rice
Plants need nitrogen to grow, but excess nitrogen – from livestock facilities, septic systems, car exhaust and other sources – that escapes into groundwater and the air can impact the environment, human health and the climate.
A new report from the Agricultural Sustainability Institute at UC Davis offers a big picture look at the scale and impacts of nitrogen in California. According to the California Nitrogen Assessment, excess nitrogen in the state comes primarily from agriculture and fossil fuel combustion.
The report, published by UC Press, offers a scientific foundation to develop practices and policies that allow nitrogen's benefits while reducing the risk.
For years, UC Agriculture and Natural Resources scientists have been working with farmers throughout the state to refine fertilizer management, irrigation efficiency and other farming practices to manage nitrogen, and the work continues.
The following are some examples of UC ANR research and extension projects underway.
App helps farmers better manage nitrogen fertilizer and water
Growers can use CropManage, developed by Michael Cahn, UC Cooperative Extension advisor in Monterey County, and UC ANR Communication Services and IT staff, to track and manage water and nitrogen fertilizer applications for their crop fields. The online application can be used on mobile devices or computers to help farmers use two tools to conserve water and make better use of nitrogen fertilizer while maintaining crop productivity and quality. Growers use the soil nitrate quick test in the field to measure the nitrogen level of their soil and the app to determine the optimal level of nitrogen fertilizer to apply based on UC ANR research on crop nitrogen use. CropManage also recommends water needs of a crop from weather station data and crop development models.
Matching nitrogen applied to crop need improves efficiency
Richard Smith, UC Cooperative Extension advisor in Monterey County, is leading several research projects evaluating the nitrogen requirements of vegetables including including cole crops, spinach, baby lettuce, a salad mix and cilantro. Smith is evaluating crop rotations with broccoli to scavenge nitrogen from the soil profile. He is also evaluating slow-release fertilizers to minimize nitrate leaching losses in shallow-rooted crops such as baby lettuce and spinach in the Salinas Valley.
Wood chips remove nitrogen in tile drain water
Using wood chips and supplemental carbon sources, Tim Hartz, UC Cooperative Extension specialist in the UC Davis Department of Plant Sciences, worked with Cahn and Smith to refine a process to remove nitrate from tile drain water, which typically is very high in nitrate. The carbon in the wood chips supports the activity of anaerobic bacteria that chemically reduce the nitrate to N2, a benign gas.
Irrigation water fertilizes vegetables
Water quality regulations in many regions of California now require farmers to report the amount of nitrogen fertilizer that they apply to their fields and the nitrate concentration of their irrigation water. Smith, Hartz and Cahn have just finished three seasons of field trials that demonstrated that the nitrate in groundwater supplied a substantial portion of the fertilizer requirements for lettuce and broccoli. By accounting for the nitrate in irrigation water and using the soil nitrate quick test to monitor soil nitrogen levels, growers may be able to significantly reduce the amount of fertilizer nitrogen they apply to vegetable crops.
Micro-irrigation offers almond growers a tool to control leaching
The majority of almond growers apply fertilizer through micro-irrigation systems and an increasing number of growers are irrigating with water that is saline. Patrick Brown, professor in the UC Davis Department of Plant Sciences, is studying how to use micro-irrigation to reduce nitrate leaching and manage soil salinity by varying the frequency of irrigation and the length of time water is applied during irrigation.
Managing irrigation to reduce nitrate leaching
To identify the best irrigation management practices to control soil salinity and to minimize nitrate leaching to groundwater, Laosheng Wu, professor and UC Cooperative Extension specialist in the UC Riverside Department of Environmental Sciences, is using computer simulation to consider soil, water, crop nitrogen demand and fertilization with irrigation methods. In collaboration with UC Cooperative Extension advisors, Wu is conducting field experiments on alfalfa in Imperial County, almonds in the Central Valley and avocados at South Coast Research & Extension Center in Orange County to validate the simulations.
Online tool being developed to estimate soil nitrogen mineralization rates
To develop a tool for growers and crop advisers to estimate soil nitrogen, Daniel Geisseler, UC Cooperative Extension specialist in the Department of Land, Air, and Water Resources at UC Davis, is gathering data throughout California to estimate field-specific nitrogen mineralization rates. This project, funded by UC ANR's California Institute for Water Resources, will use nitrogen mineralization data to develop an online tool to help growers adjust their applications of fertilizer. The tool has the potential to increase nitrogen use efficiency in crop production, resulting in lower risks of nitrate leaching to groundwater.
Nitrogen management training for Certified Crop Advisers
Between 2014 and 2016, approximately 900 Certified Crop Advisers participated in a nitrogen management training program coordinated by UC ANR's California Institute for Water Resources with support from CDFA's Fertilizer Research and Education Program. The technical and applied training improves CCAs' understanding of sound nitrogen management practices to make informed recommendations to growers.
The California Nitrogen Assessment book
The book, “The California Nitrogen Assessment: Challenges and Solutions for People, Agriculture, and the Environment,” is available for purchase at ucpress.edu. The 20-page executive summary can be downloaded for free at asi.ucdavis.edu.
This story is also available in Spanish: "La evaluación del nitrógeno en California ofrece oportunidades para mejorar http://ucanr.edu/sites/Spanish/Noticias/boletines/?uid=6884&ds=199
- Author: Kat Kerlin, (530) 752-7704, kekerlin@ucdavis.edu
California paves the way for reconciling agriculture and the environment
Nitrogen is essential for agriculture but also has health and environmental impacts. The California Nitrogen Assessment, a new report from the Agricultural Sustainability Institute at the University of California, Davis presents a big picture of the scale and impacts of nitrogen in the state. The report, published by UC Press, offers a scientific foundation to develop practices and policies that balance nitrogen's benefits and harm.
It's easy for nitrogen to become too much of a good thing, according to the report, which is the first state-level nitrogen assessment. Excess nitrogen can pollute groundwater and air, and impacts the environment, human health, and climate change.
The report shows that excess nitrogen in the state comes primarily from agriculture and fuel combustion.
“This problem was created by all of us,” said lead author Tom Tomich, director of the Agricultural Sustainability Institute at UC Davis. “Nitrogen is an issue that affects and is affected by every Californian.”
The seven-year, multi-institutional assessment identifies how much nitrogen enters the state, where it is used, and its eventual fate. It consolidates existing scientific knowledge and weighs options for addressing nitrogen management.
“Many programs in California have been recently put in place to help balance the benefit and harm of nitrogen use,” Tomich said. “The California Assessment hopes to contribute to long term solutions and we see farmers as the leaders in positive change.”
Agriculture the major source of California's nitrogen
Each year, about 1.8 million tons of nitrogen enter California. Agriculture represents the largest source of California's nitrogen imports from synthetic fertilizer, livestock feed, and nitrogen-fixing crops, which pull nitrogen from the air and convert it into a usable plant nutrient.
Nitrogen fertilizer helps California produce 21 percent of the nation's dairy commodities and more than half of the nation's fruits and vegetables.
However, vegetable and fruit crops throughout the state use only half of the nitrogen applied to them on average. For livestock, only about a quarter of the nitrogen in animal feed becomes meat or dairy products. The remaining 75 percent becomes manure, which can emit nitrogen into the air as ammonia, a known air pollutant.
Much excess nitrogen from crops leaks into soil and eventually the state's groundwater. Sixteen percent of the state's net nitrogen imports each year, accumulate in groundwater, and 11 percent of nitrogen from crop land and livestock is lost as air pollution.
Nitrogen in groundwater linked to health issues
Nitrogen leaches into groundwater as nitrate, which has been linked with blue-baby syndrome in infants, adverse birth outcomes, and various cancers. While most adults consume more nitrate through food than through drinking water, people who rely on contaminated wells may take in the majority of their nitrate through drinking water.
Parts of the state regularly fail to meet federal drinking water standards for nitrates, and previous reports have shown low-income Latino communities in agricultural regions are the most exposed to groundwater nitrate contamination.
Excess nitrogen in the environment can have detrimental impacts on crop yields, native species and biodiversity, as well.
Nitrogen, fossil fuels, and air pollution
Fossil fuel combustion is responsible for nearly a quarter of the nitrogen coming into the state in the form of nitrogen oxides, which contribute to ozone formation, and ammonia, a component of particulate matter.
Well-established scientific evidence links ozone and particulate matter to poor respiratory and heart health.
Much of the nitrogen oxides and ammonia produced in California are transported downwind from California, making the state a major exporter of nitrogen air pollution.
A very small amount of the state's nitrogen, 2 percent, is released as nitrous oxide, a potent greenhouse gas. Nitrous oxide emissions account for 4 percent of California's total greenhouse gas emissions.
Emissions have declined since 1980 as regulations have pushed fuel efficiency advancements, but nitrogen-related air pollutant levels still exceed state recommendations in many areas.
The path forward
The dispersed, “non-point” nature of nitrogen pollution makes achieving solutions especially challenging. A one-size-fits-all approach will not work for managing nitrogen.
The report highlights practices farmers and ranchers can use to decrease nitrogen losses and save money, such as reducing nitrogen application rates and timing nitrogen application closely with irrigation, practices many farmers in California already are using.
“California has amazing resources to address this issue,” said Rich Rominger, a California farmer and former Director of the California Department of Food and Agriculture. “The state has skilled and motivated farmers and a university system that can continue to dive deep into our unanswered questions about nitrogen. California is often looked to as both an agricultural innovator and an example of strong environmental policy. How we deal with nitrogen can enhance our leadership in these areas.”
The California Nitrogen Assessment was funded primarily by the David and Lucille Packard Foundation, as well as by the UC Division of Agriculture and Natural Resources (UC ANR), and the UC ANR Kearney Foundation of Soil Science.
The book is available at ucpress.edu, and summary materials are available at asi.ucdavis.edu.
More information:
Read the executive summary.
The book, The California Nitrogen Assessment: Challenges and Solutions for People, Agriculture, and the Environment,is available at ucpress.edu.
- Author: Pat Bailey,UC Davis News and Media Relations, (530) 219-9640, pjbailey@ucdavis.edu
Sacramento-area farmers and ranchers who sell their products directly to consumers generate twice as much regional economic impact per dollar of output as do area food producers who don't engage in direct marketing, reports a UC Davis agricultural economist and a team of UC Cooperative Extension researchers.
The newly released study of the four Sacramento region counties of El Dorado, Placer, Sacramento and Yolo found that direct-marketing food producers had a regional output multiplier of 1.86 compared to just 1.42 for producers not involved in direct marketing.
Direct-marketing channels include farmers markets, roadside farm stands and community-supported agriculture programs that provide consumers with regular deliveries of farm products.
“The direct marketers make up a relatively small part of the Sacramento region's agricultural sector, but this study demonstrates that these food producers generate both economic and qualitative benefits for the region,” said study leader Shermain Hardesty, a UC Cooperative Extension specialist in the UC Davis Department of Agricultural and Resource Economics.
“It's important that the economic contributions of direct-marketing farmers and ranchers be taken into consideration so that regional policies can be enhanced to support and nurture the growth of these food producers,” Hardesty said.
The regional economic impacts identified in the study are threefold: revenue received directly by the agricultural producer; a ripple effect when the food producer purchases inputs in the region; and a secondary ripple when the producer and the suppliers of goods and services to the producer, in turn, spend more money in the region on household goods and services.
The report, along with separate economic impact reports specifically for El Dorado, Placer and Yolo counties, is available online.
Sacramento region direct marketers
In the four-county Sacramento region, direct-marketing food producers are a relatively small segment of the total agricultural sector, accounting for 19 percent of the region's farms and only 4 percent of its agricultural production.
The direct-marketing farm operations tend to be smaller and more labor-intensive, and source more of their inputs locally than do nondirect-marketing operations in the area.
The new study was based on economic information gathered from 88 local farmers and ranchers, including 31 vegetable farmers, 48 orchard or vineyard growers and nine livestock producers, each of whom generated at least $1,000 in annual sales from marketing directly to consumers.
After the data were collected, they were incorporated into an economic modeling program to estimate the economic impacts of producers engaged in direct marketing.
Study highlights
Other findings from the report include:
• Sacramento region direct-market producers averaged just $164,631 in one year of sales compared to $568,105 for those not engaged in direct marketing.
• Seventy-three percent of the direct marketers also sold through wholesale channels.
• Overall, the direct-market producers generated 44 percent of their total revenues through direct-marketing channels, 55 percent through wholesale channels and 1 percent through commodity markets.
• For every $1 million of output, the direct-market producers generated a total of 31.8 jobs in the Sacramento region while the nondirect-market producers generated only 10.5 jobs.
• Direct marketers purchased 89 percent of their inputs within the region while the nondirect-market producers purchased 45 percent of their inputs in the region. This local sourcing of inputs was the primary factor responsible for the direct-market producers having a greater economic impact on the region than nondirect-market producers.
Collaborators and funding
Hardesty collaborated on the study with Libby Christensen, Erin McGuire and Gail Feenstra, all of UC Davis; and Chuck Ingels, Jim Muck, Julia Boorinakis-Harper, Cindy Fake and Scott Oneto, all with the UC Cooperative Extension.
Funding for the study was provided by the University of California Division of Agriculture and Natural Resources Competitive Grants Program.
- Author: Jeannette E. Warnert
Despite these achievements, Wright said he counts the relationships he developed with local farmers, pest control advisers, consultants, private industry, university researchers, students, UC and county staff as his greatest career accomplishments.
“When I think over my career, I think of the people who I was privileged to work with more than the projects,” Wright said.
A native of San Diego, Wright earned a bachelor's degree in plant science at Fresno State in 1972. Upon graduation, he and his wife joined the Peace Corps, spending three years working with Guatemalan native farmers.
“I did research and extension work on corn, wheat and potatoes,” Wright said. “That's what motivated me to come back to California and do graduate work at Fresno State. I wanted to work in extension.”
He praised the opportunities afforded to him during his college days at Fresno State.
“They had all kinds of farm projects we could do,” Wright said. “I had grain, cotton and vegetable projects as a student. I was doing everything from planting to harvesting. In addition to working for the school farm and private farms, I owe a lot to the professors there, who offered the applied aspects of farming along with their teaching programs.”
While completing his master's degree in agronomy in December 1980, Wright began work with UC Cooperative Extension in Tulare County. His education and work experience was immediately applicable on the job, where he was hired to work with cereal crops. Two years later, when the UCCE weed science advisor retired, Wright's research and teaching experience with weed management allowed him to take on this additional responsibility in Tulare County. When the UCCE cotton advisor retired, Wright stepped up and began to also work with cotton. Wright was later given the opportunity to cover cotton and cereal crops work with Kings County farmers.
Besides focusing much of his research on all aspects of cereals and cotton production, he also worked on weed control projects in rangeland, irrigation districts, the first herbicide-tolerant crops and later herbicide-resistant weeds in both annual and permanent crops.
“The job got bigger and changed all the time,” Wright said. “I enjoyed working in different disciplines, from controlling yellow starthistle in the foothills, to working with large- and small-acreage farmers in Tulare and Kings counties. I thrived on that.”
Wright was involved with administration and committees, serving as president of UC Agriculture and Natural Resources Academic Assembly Council, UC ANR Program Council member, and president and honorary member of California Weed Science Society. He also coordinated the building and management of California Youth Soccer Association soccer fields in Visalia.
In retirement, Wright said he plans stay in Visalia and spend time taking long walks with his young chocolate Labrador retriever. He is seeking emeritus status with UCCE and plans to work part time continuing with a few research projects that are underway. He is planning on pursuing his passion for international volunteer work and recreational outdoor activities, including camping, snow skiing, going to Morro Bay, and enjoying three grandchildren.
