Posts Tagged: water use efficiency
CASI's Mitchell helps with interview on KVPR's Valley Report - January 14, 2022
CASI's Mitchell helps with KVPR interview on climate change
January 16, 2022
CASI's very own Jeff Mitchell, along with UC ANR colleagues Mae Culumber, George Zhuang, Karl Lund, and Bob Hutmacher, helped with information on their research that is related to climate change in an interview with KVPR reporter, Kerry Klein, at the UC West Side field station on January 14th 2022. The segment was part of the Valley Report on KVPR and was titled, “Climate change resilience begins with water say these UC ag researchers.” An audio recording and a copy of the report written by Klein are available at https://www.kvpr.org/environment/2022-01-14/climate-change-resilience-begins-with-water-say-these-uc-ag-researchers
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Capture KVPR January 14, 2022JPG
DeVincentis and Mitchell talk “cover crop water use” with KMJ580’s Don York on morning Ag Report
December 28, 2021
KMJ580's Don York, who produces the daily “Ag Report” on the Fresno-based radio station, interviewed Alyssa DeVincentis and Jeff Mitchell about work they and a larger team of researchers at UC Davis conducted on water-related impacts of winter cover crops throughout the Central Valley. The interview aired at 5:05 AM on York's Tuesday, December 28th, broadcast and can be heard by clicking on the link here below.
The work that DeVincentis and Mitchell summarized with York involved ten almond orchard and tomato field sites in which side-by-side comparisons of soil water content during the winter cover cropping period from November through March were conducted from 2017 through 2019. The study sites spanned San Joaquin Valley sites in Arvin, Shafter, Five Points, and Merced, as well as Sacramento Valley locations in Davis, Durham, Orland, and Chico. Basic conclusions stemming from the work include the finding that cover crops grown in the winter growing window do not lose more soil water than fallow bare ground despite considerable dogma about the likelihood that they deplete soil water reserves during the winter growing period.
This finding adds important information that may help local Groundwater Sustainability Agencies (GSAs) create groundwater management plans that are required for compliance with SGMA, the Sustainable Groundwater Management Act. If remote-sensed imagery is used to determine a farm's overall water use, winter cover crop vegetation may appear on satellite images as a net water loss, while in actuality, because cover crops perform other functions such as improving soil water infiltration from rain, increasing soil aggregation and water holding capacity, and reducing the energy available at the soil surface by providing shade by the cover crop canopy, the net effect tends to be no additional water loss relative to a bare soil surface during the winter period.
The team that worked together on this research included then UC Davis PhD student, DeVincentis, her major professor, Samuel Sandoval-Solis, Daniele Zaccaria, Anna Gomes, then an undergraduate student at Davis and now a PhD student at Stanford University, and CASI's Mitchell.
The project is summarized in a manuscript that will be published in an upcoming issue of UC's quarterly peer-reviewed journal, California Agriculture, in 2022. A pdf copy of the research article is also available below.
Old theory drives new soil heatlh research in California!
July 7, 2020
“Generating and preserving surface residues on the soil – despite being one of the core principles of just about all of the soil health movements and government programs these days – has had very little play in most agricultural fields in California now for nearly ninety years.” That stark assertion come from experienced Cropping Systems Extension Specialist and leader of the State's Conservation Agriculture Center, Jeff Mitchell, who's been in the trenches tinkering with systems that couple residue-preserving and reduced disturbance practices for nearly 30 years.
“The body of research knowledge and experiences on the values of high residue systems is enormous,” Mitchell says, “ and yet most folks in California have not come around to them.” Scientific theory supports the role of residues in reducing soil water evaporation and weed emergence, cooling the soil, and increasing soil carbon gain. “And this theoretical underpinning is now guiding our expanded work with high residue systems to better understand the value they may have in improving biodiversity as well as the efficiency of the carbon, nitrogen and water cycles in California's food production systems,” says Mitchell about the new work that is now underway at several farm study sites throughout the State.
Most annual crop fields that you'll drive by in California typically have close to zero residue on them. “Residues are pretty much managed to make them disappear,” Mitchell observes. Yet, several studies from both irrigated and rainfed regions around the US and including our own work in Five Points have shown that when no-tillage is coupled with high residues, annual irrigation savings can be as much as 4 to 5 inches. In several areas including the Central Great Plains of the US, no-till, high residue practices have positively affected agricultural management and local farm economies with both the intensification and diversification of cropping systems. “What we're doing at this point is trying to figure out just how these residue practices might actually work in various California production systems and minimizing risks associated with transitioning to them.”
More information on these types of systems will be shared on July 23rd as part of the Desert Southwest Soil Health Webinar (https://www.eventbrite.com/e/desert-southwest-soil-health-webinar-tickets-107732693386), slated for July 23rd from 8 AM through 6 PM.
Accompanying photo caption
High residue, no-tillage and cover cropped surface soil conditions achieved in 21-year conservation agriculture research study in Five Points, CA showing the extent of residue cover that can be achieved when these practices are coupled together.
Residue 2020
A More Water Efficient Avocado?
Here's a pretty technical report of water efficiency in avocado - the amount of water it takes to make fruit. It looks like there might be some varieties that could produce more fruit with less water. It's a promising start to selecting a tree that could produce under the increasing drought conditions found in avocado growing areas.
Evaluation of leaf carbon isotopes and functional traits in avocado reveals water-use efficient cultivars
Plant water-use efficiency (WUE) describes the ratio of carbon gain to water loss during photosynthesis. It has been shown that WUE varies among crop genotypes, and crops with high WUE can increase agricultural production in the face of finite water supply. We used measures of leaf carbon isotopic composition to compare WUE among 24 cultivars of Persea americana Mill (avocado) to determine genotypic variability in WUE, identify potentially efficient cultivars, and to better understand how breeding for yield and fruit quality has affected WUE. To validate carbon isotope measurements, we also measured leaf photosynthetic gas exchange of water and carbon, and leaf and stem functional traits of cultivars with the highest and lowest carbon isotope composition to quantify actual WUE ranges during photosynthesis. Our results indicate large variation in WUE among cultivars and coordination among functional traits that structure trade-offs in water loss and carbon gain. Identifying cultivars of subtropical tree crops that are efficient in terms of water use is critical for maintaining a high level of food production under limited water supply. Plant functional traits, including carbon isotopes, appear to be an effective tool for identifying species or genotypes with particular carbon and water economies in managed ecosystems.
Read the article:
https://www.sciencedirect.com/science/article/pii/S0167880918301828
avocado fruit