Posts Tagged: Nitrogen

Growing cereal crops with less fertilizer

Discovery could reduce nitrogen pollution, save farmers billions

Researchers at the University of California, Davis, have found a way to reduce the amount of nitrogen fertilizers needed to grow cereal crops. The discovery could save farmers in the United States billions of dollars annually in fertilizer costs while also benefiting the environment.

The research comes out of the lab of Eduardo Blumwald, a distinguished professor of plant sciences, who has found a new pathway for cereals to capture the nitrogen they need to grow.

The discovery could also help the environment by reducing nitrogen pollution, which can lead to contaminated water resources, increased greenhouse gas emissions and human health issues. The study was published in the journal Plant Biotechnology.

Nitrogen is key to plant growth, and agricultural operations depend on chemical fertilizers to increase productivity. But much of what is applied is lost, leaching into soils and groundwater. Blumwald's research could create a sustainable alternative.

“Nitrogen fertilizers are very, very expensive,” Blumwald said. “Anything you can do to eliminate that cost is important. The problem is money on one side, but there are also the harmful effects of nitrogen on the environment.”

A new pathway to natural fertilizer

Blumwald's research centers on increasing the conversion of nitrogen gas in the air into ammonium by soil bacteria — a process known as nitrogen fixation.

Legumes such as peanuts and soybeans have root nodules that can use nitrogen-fixing bacteria to provide ammonium to the plants. Cereal plants like rice and wheat don't have that capability and must rely on taking in inorganic nitrogen, such as ammonia and nitrate, from fertilizers in the soil.

“If a plant can produce chemicals that make soil bacteria fix atmospheric nitrogen gas, we could modify the plants to produce more of these chemicals,” Blumwald said. “These chemicals will induce soil bacterial nitrogen fixation and the plants will use the ammonium formed, reducing the amount of fertilizer used.”

Blumwald's team used chemical screening and genomics to identify compounds in rice plants that enhanced the nitrogen-fixing activity of the bacteria.

Then they identified the pathways generating the chemicals and used gene editing technology to increase the production of compounds that stimulated the formation of biofilms. Those biofilms contain bacteria that enhanced nitrogen conversion. As a result, nitrogen-fixing activity of the bacteria increased, as did the amount of ammonium in the soil for the plants.

“Plants are incredible chemical factories,” he said. “What this could do is provide a sustainable alternative agricultural practice that reduces the use of excessive nitrogen fertilizers.”

The pathway could also be used by other plants. A patent application on the technique has been filed by the University of California and is pending.

Dawei Yan, Hiromi Tajima, Howard-Yana Shapiro, Reedmond Fong and Javier Ottaviani from UC Davis contributed to the research paper, as did Lauren Cline from Bayer Crop Science. Ottaviani is also a research associate at Mars Edge.

The research was funded by the Will W. Lester Endowment. Bayer Crop Science is supporting further research on the topic.

Editor's note: Blumwald is affiliated with UC Agriculture and Natural Resources through the Agricultural Experiment Station at UC Davis.

New ‘big data’ tools help California wheat farmers reduce fertilizer guesswork

Growers in California grapple with plenty of climate uncertainty – but a new set of tools can help wheat farmers make crucial fertilizer decisions with more precision and confidence.

An interactive website integrates these tools – developed or adapted by researchers at the University of California, Davis and University of California Cooperative Extension – that provide farmers with recommendations for applying nitrogen fertilizers, specific to their own sites and conditions.

“The system is made for being flexible, for being reactive – and not having a cookie-cutter approach, year-in and year-out, because the weather is not cookie-cutter, year-in and year-out,” said Mark Lundy, UC Cooperative Extension specialist in the UC Davis Department of Plant Sciences.

While factoring in those weather variables, the management tool also draws data from two indicators of nitrogen sufficiency or deficiency: the results of a soil nitrate quick test (a simple test previously used in vegetable crop systems along the coast), and comparisons of plant health in the broader field to that in a “nitrogen-rich reference zone” (a practice originally developed in the Midwest).

Using them in tandem, in the context of California wheat growing, is a novel approach. In a Nov. 4 webinar, Lundy will introduce the use of the nitrogen-rich reference zone, a small area in a field where extra fertilizer is added at the beginning of the season.

“This project is a unique example of digital agriculture at work in an applied setting,” he explained. “We are integrating ‘big data' sources like site-specific soil and weather data, as well as satellite, drone and other sensor measurements into an interactive web interface. This allows users to receive straightforward yet highly customized recommendations from somewhat complex agronomic models.”

Since 2019, agronomists from UC Davis and UCCE have been testing these tools in real-world conditions, with support from the California Department of Food and Agriculture's Fertilizer Research and Education Program and a Natural Resources Conservation Service Conservation Innovation Grant.

The team conducted 11 on-farm demonstrations in fields representing a wide range of agroecosystems, including the Sacramento Valley, San Joaquin Valley, Delta region, and Tulelake Basin.

Fritz Durst, a western Yolo County-based grower who participated in one of the case studies, said that the process of gathering the data was “actually pretty simple” and the tool “eliminates much of the guesswork” for managing nitrogen fertilizers.

“This tool is extremely helpful for me to make decisions about the most efficient and cost-effective method for applying nitrogen to my wheat,” Durst said.

In addition to potentially increasing crop productivity and farmer net-income, the tool can benefit the environment by reducing the amount of nitrate leaching from fertilizer applications, according to Lundy.

“It's not only trying to say how much fertilizer to put down, sometimes it's trying to confirm you don't really need any fertilizer,” he said.

More resources and events related to the Nitrogen Fertilizer Management Tool for California Wheat – including demonstration activities – will appear on the UC Small Grains blog.

UC is offering a nitrogen management course for certified crop advisors and the general public

The University of California has opened registration for a seven-part video course on nitrogen management. The series, taught by UC researchers and extension specialists, begins May 10.

The course is open to anyone interested nitrogen management or seeking certified crop advisor continuing education units related to nutrient or soil and water management. The curriculum addresses all the learning objectives set forth by the American Society of Agronomy for the new California Nitrogen Management Specialty Exam. Taking the course helps certified crop advisors prepare for the exam, but doesn't substitute for taking and passing the exam.

The course topics, release dates and continuing education units for the series are:

• Environmental impacts of nitrogen losses, May 10, 0.5 unit
• Nitrogen cycling soil transformations, May 17, 1.0 unit
• Nitrogen cycling plant utilization, May 24, 1.0 unit
• Nitrogen sources, May 31, 1.0 unit
• Nitrogen budgeting, June 7, 1.0 unit
• Irrigation and nitrogen management, June 14, 1.0 unit
• California cropping systems, June 21, 2.0 units

Registration for the course is $120. Students with a valid educational email address (.edu) receive a 50% discount. July 31 is the last day to register and Sept. 30 is the last day to access the course content.

To register or for more information visit http://ucanr.edu/NitrogenCourse

If additional information is needed, contact course organizer Sat Darshan Khalsa at sdskhalsa@ucdavis.edu, or visit the FAQ page.

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UC ANR publishes nitrogen management advice for fruit, nuts and other crops

California growers can download a new series of publications summarizing efficient nitrogen management practices from UC Agriculture and Natural Resources. The publications are designed to assist growers in complying with state regulations for tracking and reporting nitrogen fertilizer applied to crops, in an effort to prevent nitrogen from leaching into groundwater.

The science-based publications are associated with a series of trainings for growers and Certified Crop Advisers to develop efficient nitrogen management practices, an effort coordinated by UC ANR's California Institute for Water Resources.

“Our role is to provide farmers, agricultural consultants and policymakers the best science possible for making decisions on managing and protecting California groundwater,” said Doug Parker, director of the water institute.

The free publications, created from training materials, lessons learned from the training sessions and from additional UC research, can be downloaded at http://ucanr.edu/nmgmtpublications. 

The following publications are now available for download:

·         Principles of Nitrogen Cycling and Management

·         Irrigation and Nitrogen Management

·         Nitrogen Management for Nut Crops

·         Nitrogen Management for Deciduous Fruit and Grapes

·         Nitrogen Management for Citrus and Avocado

·         Nitrogen Management for Cool-Season Vegetables

·         Nitrogen Management for Strawberry Production

·         Nitrogen Management for Processing Tomato

·         Nitrogen Management for Corn on California Dairies

The publications were authored by Parker of California Institute for Water Resources; Patrick Brown, professor in the UC Davis Department of Plant Sciences; Allan Fulton, UC Cooperative Extension advisor, Tehama County; Tim Hartz, UC Cooperative Extension specialist emeritus, UC Davis Department of Plant Sciences; Dan Munk, UC Cooperative Extension advisor, Fresno County; Daniel Geisseler, UC Cooperative Extension specialist, UC Davis Department of Land, Air & Water Resources; Michael Cahn, UC Cooperative Extension advisor, Monterey, Santa Cruz and San Benito counties; Richard Smith, UC Cooperative Extension advisor, Monterey, Santa Cruz and San Benito counties; Marsha Campbell, UC Cooperative Extension advisor emeritus, Stanislaus County; Sat Darshan Khalsa, UC Davis project scientist; and Saiful Muhammad, UC Davis graduate student.  

Developed in 2014, the training program has been offered at 11 different locations around the state, most recently in Fresno. More than 1,000 Certified Crop Advisers have taken the training.

“Based on course evaluations, the percentage of participants with good-to-complete understanding of nitrogen management increased after the training,” Parker said. “In addition, the participants found the presenters very knowledgeable and informative. Most importantly, the majority of participants felt they were better prepared to address nitrogen mitigation regulatory requirements after the training.”

The nitrogen management training curriculum was developed by a group of UC ANR faculty, specialists and advisors. The first day focuses on the nitrogen cycle in crop production systems, nitrogen sources, irrigation and nitrogen management, and nitrogen budgeting. The second morning covers annual and permanent crops and nitrogen planning practices.

For more information on the nitrogen management training materials, visit http://ciwr.ucanr.edu/NitrogenManagement.

The Nitrogen Management Training and Certification Program is a joint effort between the California Department of Food and Agriculture, UC Agriculture and Natural Resources, California Association of Pest Control Advisers' Certified Crop Adviser Program and the Regional Water Boards.

 

California nitrogen assessment presents opportunities for improvement

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

 

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