Posts Tagged: forage crops
Drip irrigation in arid regions can cut greenhouse gas emissions, improve air quality
Study at Desert Research and Extension Center highlights agriculture's sustainability role
Under the blistering sun of Southern California's Imperial Valley, it's not surprising that subsurface drip irrigation is more effective and efficient than furrow (or flood) irrigation, a practice in which up to 50% of water is lost to evaporation.
But a recent study also concludes that drip irrigation can dramatically reduce greenhouse gas emissions from soil – which contribute to climate change and unhealthy air quality in the region – without sacrificing yields of forage crops alfalfa and sudangrass.
“It was really exciting to see,” said lead author Holly Andrews, a National Science Foundation postdoctoral fellow at the University of Arizona. “The crop yield was at least maintained and in some cases increased, but the water use and gaseous emissions were especially decreased under drip irrigation.”
Desert REC crucial to collecting data
Andrews and her colleagues gathered data from field studies at University of California Agriculture and Natural Resources' Desert Research and Extension Center, a crucial hub of desert agriculture research for more than 100 years. Studies in that context are increasingly important, as much of California and the Southwest becomes hotter and drier.
“We already have this history of looking at drip irrigation at this site, so our study was trying to build on that,” said Andrews, who lauded Desert REC's facilities and staff.
In their study published in Agriculture, Ecosystems & Environment, researchers found that – in comparison to furrow irrigation – drip irrigation in alfalfa slashed per-yield soil carbon dioxide emissions by 59%, nitrous oxide by 38% and nitric oxide by 20%.
Nitrous oxide is a greenhouse gas with nearly 300 times more warming potential as carbon dioxide, and nitric oxide is a precursor to ozone and major contributor to air pollution.
While drip irrigation only decreased water demand 1% in alfalfa, the practice led to a substantial 49% decrease in irrigation for sudangrass. For more fertilizer-intensive sudangrass, drip irrigation also reduced soil emissions of nitrous oxide by 59% and nitric oxide by 49% – the result of drip irrigation making those fertilizers more efficient.
Water management can help mitigate climate change
Studying alfalfa and sudangrass – forage crops with very different fertilizer requirements – was a strategic choice by the researchers. They are number one and number three on the list of most widely grown crops by acreage in the Imperial Valley (Bermudagrass, another forage crop, is number two).
With so much land dedicated to producing these crops, the adoption of drip irrigation at scale could deliver significant benefits to residents' health and quality of life.
“The thought that saving water can increase yields while lowering the emission of trace gases that affect regional air quality and Earth's climate is quite encouraging,” said Pete Homyak, an assistant professor of environmental sciences at UC Riverside who contributed to the study. “This is especially true for the Imperial Valley, an arid region where water is a limited resource and where residents are exposed to bad air quality.”
Homyak, who is affiliated with UC ANR through UC Riverside's Agricultural Experiment Station, said that this study illustrates how changes in water management can substantially mitigate agricultural impacts on the environment.
The study findings should encourage growers to replace furrow irrigation systems with drip irrigation infrastructure – especially in combination with financial incentives from the state, such as cap-and-trade and carbon credit programs, that can help defray high installation costs.
“It really is worthwhile if you're thinking sustainability and environmental activism in how agriculture can actually support climate change mitigation,” Andrews explained. “These practices might be a way that we can start to change that picture a little bit – and make agriculture more sustainable by tailoring irrigation management to local climate conditions.”
In addition to Andrews and Homyak, the other study authors are Patty Oikawa, California State University, East Bay; Jun Wang, University of Iowa; and Darrel Jenerette, UC Riverside.
/h3>/h3>/h2>2018 Kearney Alfalfa and Forage Field Day: Presentations now available
This year's Alfalfa and Forage Field Day held on September 19, 2018 at the Kearney Agricultural...
2018 Kearney Alfalfa and Forage Field Day Agenda
The agenda for the annual Kearney Alfalfa and Forage Field Day is set. Where: Kearney Agricultural...
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2015 Western Alfalfa & Forage Symposium
2015 Western Alfalfa & Forage Symposium will be held in Reno, Nevada on December 2-4 at the...
Kearney’s 2013 alfalfa and forage meeting provides diverse tools to the agriculture community.
The recent alfalfa and forage meeting at Kearney attracted about 100 growers and pest control advisors.
Shannon Mueller, UC Cooperative Extension advisor and director in Fresno County, agronomy, alfalfa, hay, forage crops, honeybees, seed oil crops, and dry beans, indicated that grower knowledge of the local pest and disease pressure and selection of an alfalfa variety with desired resistance qualities is an effective IPM tool for managing pests and disease in alfalfa crops.
Dan Putnam, extension specialist in the Department of Plant Sciences at UC Davis, agronomy, alfalfa and forage crops, alternative field crops, cellulosic energy crops, crop ecology, shared that some of the nitrogen produced by alfalfa (a legume) remains and is available for subsequent crops. Current research has a goal of developing alfalfa’s nitrogen credit to help manage nitrogen fertilizer supplementation for non-legume rotational crops (like wheat). Putnam also shared the potential value of sorghum as a summer irrigated forage crop for dairy and livestock production that requires less water and nitrogen as compared to corn (California’s main forage crop). Research on the sorghum is ongoing, with benefits and limitations being identified.
Michelle Leinfelder-Miles, UC Cooperative Extension advisor in San Joaquin, Contra Costa, Sacramento, Solano and Yolo counties, crop production, soil and water quality, the Delta, discussed concerns and management strategies related to the co-existence of Roundup Ready (RR) alfalfa and conventional alfalfa. Gene flow between seed producing alfalfa fields has been observed. Gene flow between hay producing alfalfa fields is mainly prevented by management barriers, particularly the cutting of hay at a stage that minimizes any seed development. Best practices to allow growing and separating both RR and conventional alfalfa were discussed. Additionally, growers can use test strips that allow easy and quick detection al RR alfalfa if customers do not want any RR alfalfa.
Jeffery Dahlberg, director at Kearney Agricultural Research & Extension Center, plant breeding, agronomy, field crops, sorghum, plant production, plant genetics, discussed sorghum variety trials designed to assess many characteristics, including water use, fertility, forage quality and yield. Dahlberg indicated that sorghum serves as a grain and forage crop for livestock, and biofuel crop.
Robert Hutmacher, cooperative extension specialist and director at West Side Research & Extension Center, cotton production issues, water stress, nutrient management, indicated that water conservation is a high priority. Hutmacher highlighted water timing and reduction research that indicated that although yields are lowered with less water, acceptable sorghum crop yields can still be obtained. Yields of grain sorghum were impacted less than yields of forage sorghum with reduced water use.
Steven Wright, UC Cooperative Extension advisor in Tulare and Kings counties, cotton, small grains, weed control, discussed how nitrogen/wheat variety management strategies help maximize both yield and protein levels while minimizing ground water contamination in growing areas.
Larry Godfrey, UC Cooperative Extension Specialist in the Department of Entomology, UC Davis, entomology, discussed the Blue Alfalfa Aphid, which caused extensive economic damage throughout California last year. The Blue Alfalfa Aphid was a major problem in the 1970s, and a minor problem in the interim. The pest management materials that were effective historically were not effective last year. New pest management strategies have been developed and a new use registration and/or section 18 use permit are pending, hopefully in time for the 2014 alfalfa growing season.
Kurt Hembree, UC Cooperative Extension Specialist in Fresno County, weed management strategies in crop and non-crop settings, discussed weed management strategies for RR and conventional alfalfa stands. Hembree indicated that best practices are to design weed management strategies according to existing and anticipated weeds with extra weed control effort during early stand development. Hembree stressed that if growers want to preserve the benefits created by RR alfalfa, they need to reduce the chances of weed resistance to glyphosate with escapes control, mode of action rotation, and/or tank-mixing with other herbicides.
For more information, please look at the California Ag Today blog.
Forage and Alfalfa Day attendees visiting research plots at Kearney. (photo by P Cavanaugh)