- 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
The University of California Division of Agriculture and Natural Resources (UC ANR) has appointed Soroosh Sorooshian as chair of the Rosenberg International Forum on Water Policy. Sorooshian is distinguished professor of civil and environmental engineering and earth sciences at UC Irvine.
The forum, a program of UC ANR's California Institute for Water Resources, was launched in 1996 with an endowment gift from the Bank of America honoring then-retiring bank chairman and CEO Richard Rosenberg. Experts from all over the world convene at the Rosenberg Forum to identify ways in which conflict in the management of water resources can be reduced and to promote science-based policies to govern the management of water resources.
“I'm delighted that the University of California, through the Rosenberg International Forum on Water Policy, is carrying out the vision of Richard Rosenberg in reducing conflict in water resources management through dialogue and information sharing between scientists and policymakers,” said UC President Janet Napolitano. “We are pleased that Dr. Soroosh Sorooshian, with his wide range of expertise and prominence in the international community, will be leading this important work as the incoming chair of the Rosenberg Forum.”
The forum meets biennially at different locations around the world. Previous forums have been held in San Francisco (1997), Spain (1999 and 2008), Australia (2002), Turkey (2004), Canada (2006), Argentina (2010), and Jordan (2013). The most recent forum was in January 2016 in Panama City, Panama.
“Over the past 30 years, the Rosenburg Forum has raised UC's stature in international water conflict resolutions,” said Glenda Humiston, UC vice president for Agriculture and Natural Resources. “The forum will continue to develop new approaches and solutions to addressing water problems around the world under the leadership of Dr. Sorooshian, an accomplished and brilliant scientist.”
Attendance at the forum is by invitation and limited to 50 water scholars and senior water managers. Participants devote their time at each forum to discussions of previously commissioned papers, which are published following the meeting. The conclusions and findings of each forum are also published.
“The need for approaches and solutions to securing clean, reliable water sources crosses all political, ethnic and territorial boundaries,” said UC Irvine Chancellor Howard Gillman. “But how we get to those solutions varies greatly, depending on culture, financial resources and social norms. I'm confident that Soroosh Sorooshian will be able to find ways to transcend the differences and find workable solutions for all. I'm proud that UCI can contribute to making great progress on such global issues.”
Sorooshian is also director of the Center for Hydrometeorology and Remote Sensing in the Henry Samueli School of Engineering at UC Irvine. His fields of interest include hydrometeorology, water resources systems, climate studies and application of remote sensing to water resources issues in arid and semi-arid zones. Sorooshian is a member of the National Academy of Engineering and has garnered many international and national awards for his work. His appointment was effective April 1, 2016.
“I am honored to be appointed chair of the Rosenberg Forum and serve after my dear colleague Henry Vaux Jr., professor emeritus of resource economics at the University of California Riverside, who has filled this role since the forum was established,” Sorooshian said. “I've also had the pleasure of meeting Mr. Rosenberg. He is a remarkable and humble man whose wisdom and knowledge of international issues are unmatched. I thank him for sharing his vision of the role the Rosenberg Forum can play in addressing international water issues, and I look forward to this new opportunity.”
Drought management experts from Israel and Australia will join U.S. scientists in California for a workshop in Modesto on Jan. 12 and 13. Growers, crop consultants, irrigation practitioners, state agency members and others are invited to participate.
The two-day event, “Proven Solutions to Drought Stress: Water Management Strategies for Perennial Crops with Limited and Impaired Water Supplies,” is designed to foster conversation on a variety of drought management aspects and strategies. The drought workshop will be held at the Modesto Centre Plaza at 1150 9th Street in Modesto.
“California, Israel and Australia have all faced recurring drought conditions of varying severity and duration,” said James Ayars, research agricultural engineer of USDA Agricultural Research Service in Parlier, Calif., who spearheaded the event to bring together this prestigious group of scientists. “In view of more frequent and more severe recurring droughts in the years to come, it makes sense for us to pool our knowledge and plan more strategically for the future.”
Other speakers include Shabtai Cohn, head of Israel's Agricultural Research Organization Soil, Water and Environmental Sciences Institute, John Hornbuckle, associate professor at Deakin University in Australia, and other researchers from Israel and Australia.
This workshop is sponsored by the USDA Agricultural Research Service, UC Agriculture and Natural Resources (UC ANR), UC California Institute for Water Resources and the Israel Ministry of Agriculture's Agricultural Research Organization.
“We hope to share expertise gained from experiences in our respective countries and learn new approaches for growing crops with limited water and poor quality water under the prospect of increased climate variability and change,” said Daniele Zaccaria, UC ANR Cooperative Extension specialist in agricultural water management in the Department of Land, Air and Water Resources at UC Davis and one of the event organizers. “Although Australia and Israel have very different climatic and socioeconomic conditions, there may be drought management strategies and policies that work in California that they can apply, and they may have practices and policies that we can adapt to address issues in California.”
Registration is $80 and includes lunch for both days. Dec. 18 is the deadline for early registration. After Dec. 18, registration is $120 until Jan. 1, 2016, and $150 after Jan. 1. There will be no on-site registration.
Certified crop advisers can earn continuing education units: Soil & Water Management 12.0 CEU and Crop Management 0.5 CEU.
To see the agenda and to register, please visit http://www.droughtmgt.com.
Lodging is available next to the Modesto Centre Plaza at the DoubleTree Hotel at 1150 9th Street in Modesto.
- Author: Pamela Kan-Rice
To help farmers make the best use of the water they have available, a series of new and updated drought tips fact sheets has been developed by UC ANR scientists and funded by the California Department of Water Resources.
“These drought tips provide irrigation management recommendations for a broad range of agricultural crops and under different water supply conditions,” said Daniele Zaccaria, UC ANR Cooperative Extension agricultural water management specialist at UC Davis and major organizer of the drought tip series. “The information in these tips will be of practical use for growers and other water-related stakeholders now and into the future as our agricultural community continues to adapt to climate variability and to a changing water supply situation.”
UC ANR scientists have identified best management practices for a wide range of annual and permanent crops and irrigation systems and methods during the drought. In the drought tips series, they also give advice for managing soil salinity and using shallow groundwater for irrigating crops. For beef cattle, they provide recommendations for culling herds and feeding to supplement grazing.
The following drought tips are currently available for free download at http://ucanr.edu/drought-tips:
- Drought strategies for alfalfa
- Drought management for California almonds
- Use of shallow groundwater for crop production
- Drought strategies for walnuts
- Fog contribution to crop water use
- Reclaiming Saline, Sodic and Saline-Sodic Soils
Decades of UC ANR research underlie the information contained in the drought tips. In the 1970s and again in the 1990s, UC ANR partnered with DWR to develop a series of drought management fact sheets.
“DWR has worked with UC ANR to update the drought tips and make sure the latest and best information on water management is available to growers,” said Peter Brostrom, DWR Water Use Efficiency Section Manager.
The California Institute for Water Resources, which coordinates water-related research and extension education across the 10 UC campuses and UCANR, has the drought tips and more drought resources online at http://ciwr.ucanr.edu.
“Even if El Niño brings rain this fall, water scarcity will continue to impact California farmers,” said Doug Parker, director of UC ANR's California Institute for Water Resources. “As climate change continues to reduce the average annual snowpack, it is likely that droughts in California will become more frequent and severe in the years to come.”
UC ANR's California Institute for Water Resources and the California Department of Water Resources also offer drought-related information in a series of videos. Water experts from UC and other agencies and institutions have recorded presentations on high-priority drought topics. Currently 38 videos can be accessed for free on computers and mobile devices at http://ucanr.edu/insights.
UC Agriculture and Natural Resources researchers and educators draw on local expertise to conduct agricultural, environmental, economic, youth development and nutrition research that helps California thrive. Learn more at ucanr.edu
High-volume hydraulic fracturing, or fracking, a form of natural gas and oil extraction, is water-intensive and could exacerbate water stress. Gwen Arnold, professor in the Department of Environmental Science and Policy at UC Davis, is examining efforts to locally restrict high-volume hydraulic fracturing.
“There's a lot of concern over water pollution and water use in communities,” said Doug Parker, UC ANR California Institute for Water Resources director. “We're looking at the characteristics of communities that have voted on measures to restrict the practice of fracking, both where the measures have failed and where they've passed.”
Parker expects that people on either side of the issue will be able to use the study's finding to better understand differing viewpoints. Decision-makers who may be contemplating policy action on fracking will also benefit from seeing the range of relevant policies passed by other jurisdictions and the conditions that appear to favor or discourage adoption of the policies.
Another research project is assessing the Integrated Regional Water Management approach to address the lack of safe and affordable water in disadvantaged communities throughout the state. In 2011, the California Department of Water Resources funded seven pilot projects to develop models for improving water supplies for these communities.
“We want to take a look at how well Integrated Regional Water Management worked, whether it is meeting the needs of providing safe, affordable drinking water,” Parker said.
Jonathan London, professor in the Department of Human Ecology and director of the Center for Regional Change at UC Davis, and Carolina Balazs, UC presidential postdoctoral research fellow at UC Davis, are evaluating the impact of those efforts in Inyo-Mono counties, Santa Cruz, Los Angeles County, Kings Basin, North Coast, Imperial Valley and Coachella Valley.
- Roya Bahreini, professor in the Department of Environmental Sciences at UC Riverside, is looking at the relationship between water management and air quality in the Salton Sea region of southern California, where low water levels are leading to increased dust from the dry lakebed.
- Igor Lacan, UC ANR Cooperative Extension advisor in San Mateo-San Francisco counties, is investigating the performance of trees used in streetside stormwater management facilities, which are increasingly common in cities across California as communities look for ways to increase groundwater infiltration.
- Bruce Linquist, UC ANR Cooperative Extension specialist in the Department of Plant Sciences UC Davis, is quantifying methylmercury loads from rice fields to determine whether they may be of concern.
- Clarissa Nobile, professor in the School of Natural Sciences at UC Merced is using a high-tech metagenomic approach to research a potential problem for groundwater wells across the state: biofouling, which has the potential to be a costly challenge.
Learn more about these and other California Institute for Water Resources research projects by visiting http://ciwr.ucanr.edu/CIWR_Making_a_difference.
The California Institute for Water Resources integrates California's research, extension, and education programs to develop research-based solutions to the state's water resource challenges. An initiative to maintain and enhance healthy families and communities is part of the UC Agriculture and Natural Resources Strategic Vision 2025.