UC Blogs
Leaving crop residues in the field improves water use efficiency
Managing crop residues to essentially make them disappear has been the norm in California agriculture.
But a growing body of research, and experience with conservation tillage on thousands of acres of Central Valley farmland, is showing that reducing tillage and leaving crop residues on the soil surface can improve water use efficiency.
“Crop residues are an inevitable feature of agriculture,” Jeffrey Mitchell, cropping systems specialist in the Department of Plant Sciences, UC Davis, wrote in the April-June 2012 issue of California Agriculture journal. “Because no harvest removes all material from the field, the remaining plant matter accumulates and is typically returned to the soil through a series of mixing and incorporating operations involving considerable tractor horsepower, an array of tillage implements and cost.”
Conservation tillage is a suite of low-impact cultivation practices that includes leaving crop residues on the soil surface and planting new crops on top, significantly decreasing the number of tractor passes needed to prepare fields for planting. In turn, growers reduce their fuel, labor and maintenance costs, and less dust and pollution gets into the air.
In two field studies conducted at the UC West Side Research and Extension Center in Five Points, no-tillage and standard tillage operations were compared in a corn/wheat rotation. Mitchell and colleagues found that 0.89 and 0.97 inches more water was retained in the no-tillage soil than in the tilled soil.
And in three field studies on crop residue coverage, about 0.56, 0.58 and 0.42 inches more water was retained in residue-covered soil than in bare soil following 6 to 7 days of overhead sprinkler irrigation. The full study results are published in the April-June 2012 California Agriculture journal.
The authors estimated that coupling no-tillage with practices that preserve high residues on the soil surface can reduce evaporative losses during the summer by about 4 inches (13 percent), assuming a seasonal evapotranspiration demand of 30 inches.
In widespread use in other regions of the country, conservation tillage practices appear to be catching on in California. In surveys conducted by Sustainable Conservation and the UC Conservation Agriculture Systems Initiative, the amount of farmland under conservation tillage statewide grew by nearly 20 percent between 2008 and 2010, to about 1 million acres.
Mitchell and colleagues warn that a number of practical factors must be addressed before a wholesale transformation to no-tillage, residue-preserving production can be envisioned in California: “These include the relative ease with which a farm's existing cropping mix might be converted to no-till, the need for and cost of new equipment and the learning curve for new management practices.”
A two-year study compared soil water content in tilled (right, subsoil ripped) and no-tillage (left) plots.
The Hostest with the Mostest
You're sitting in your back yard or at a park and a mosquito bites you. You're the host whether you like it or not. You just hope that this isn't an...
Tara Thiemann is researching bloodfeeding patterns of Culex mosquitoes. (Photo by Kathy Keatley Garvey)
Tara Thiemann working in the lab. (Photo by Kathy Keatley Garvey)
UCCE launches Northern California obesity study, 'Naturalist' program
UC Cooperative Extension nutrition researchers are in the process of selecting five schools each from Shasta and Butte counties to pilot a nutrition and extension program that university researchers will study to learn how to motivate kids to choose healthy habits, the Redding Record Searchlight reported.
The project is funded with a $500,000 grant from UC Agriculture and Natural Resources.
"We are going to support the school(s) to develop a stronger wellness program that rewards healthy eating and physical activity," said Concepción Mendoza, UCCE advisor in Shasta County, nutrition, family and consumer sciences.
UC Cooperative Extension specialist Patricia Crawford, nutrition, told reporter Joe Szydiowski that people's palettes depend on four criteria: easy to get, cheap, tastes good, and heavily advertised.
Those combine to provide a strong push for people to eat unhealthy food.
"We have to go against the forces to reach out and get foods that will make us healthy," she said. One of the best ways to do that, Crawford said, is by providing students with easy access to cold, clean water.
The program could be extended to the state and national level if it's successful after the two years of study.
UCCE offers 'California Naturalist' program in Truckee
Aspiring naturalists may enroll in a 40-hour course this summer at UC Berkeley's Sagehen Creek Field Station near Truckee to receive classroom and field training in science, problem-solving, communication and community service, according to the Sierra Sun.
The 'California Naturalist' course fee of $350 includes course instruction, a PDF textbook, graduation certificate, website support and registration as a UC "California Naturalist."
An Uncommon Bee
Sometimes you get lucky.While watching floral visitors foraging last week in our rock purslane (Calandrinia grandiflora), we noticed a tiny black...
Female leafcutting bee, Megachile gemula, on rock purslane. (Photo by Kathy Keatley Garvey)
Female leafcutting bee, Megachile gemula, exiting rock purslane. (Photo by Kathy Keatley Garvey)
UCCE supports Tahoe fire awareness week and Oroville nutrition decathlon
As part of Tahoe Fire Awareness Week, May 26 to June 3, Tahoe Basin fire agencies and partners, including Tahoe Regional Planning Agency and the University of California and Nevada Cooperative Extensions, are sponsoring a series of free webinars to help individuals and communities learn how to become more fire adaptive, reported the Record-Courier. Each webinar will be held from noon to 1 p.m. and will be recorded and archived for later viewing.
“With 2012 shaping up to be a high risk year for wildfires, the more people can prepare to survive the threat the better we all will be,” said Susan Kocher, University of California Cooperative Extension advisor, natural resources.
Kocher speaks in session three of the seminar series on May 30 about defensible space landscaping. The session also includes a talk by Wendy West, UC Cooperative Extension program representative, natural resources, titled "Learning how to garden at Lake Tahoe."
See the UCCE Lake Tahoe Basin Wildfire Awareness Week website for more details and links to the webinars.
Nutrition Decathlon
UC Cooperative Extension in Butte County offers local schools a "Nutrition Decathlon," a full-day nutrition and physical activity program, reported the Oroville Mercury-Register.
UCCE is beginning its Nutrition Decathlon season, hosting activities at schools that are making changes on their campuses, said Jona Pressman, UCCE program manager, nutrition.
"To participate, they need to be making significant changes with physical activity and nutrition," Pressman said.
At Helen Wilcox School last Friday, students ran, jumped, balanced on beams, tossed balls into nets, hopped in sacks, ducked through hoops, balanced bean bags on their heads, crawled through tubes, did pushups and lifted slight weights, reported Barbara Arrigoni, Mercury-Register staff writer.