Funded Projects
In 2024, the Foundation funded its fifth round of research projects. A synopsis of the research projects selected by the Foundation is provided below.
CAFRF Research Funding
MAPPING ALFALFA HAY WINDROW VOLUME AND YIELD USING DRONE IMAGERY submitted by Ahmed Kayad, Intermountain Research and Extension Center (IREC), UCANR
Summary: Currently there is not a precise and cost-effective technique for alfalfa yield mapping at the field scale. We suggest that mapping the volume of the alfalfa hay, windrow could be utilized to assess and measure alfalfa yield across the field. Drone images will be used to create a 3D model of the hay windrow to estimate hay volume and subsequently yield variability. Initial findings from a single cut of alfalfa in the 2023 season demonstrated the capability of this method to accurately assess alfalfa yield.
FALCATA ALFALFA VARIETY TRIALS IN TEHAMA COUNTY, CA submitted by Ryan J. Hill, UCCE Tehama, Glenn and Shasta Counties Counties
Summary: Falcata alfalfas are yellow-flowered, as opposed to the more common, purple-flowered sativa subspecies used for hay production in California. Falcata alfalfas tend to have a fibrous root system, a lower root crown that is resilient to heavy grazing, prostrate growth, and lower yield than sativa alfalfas. The falcata subspecies is also far more drought tolerant than the sativa subspecies but falcata germplasm is largely unexploited, particularly in California. The first step in development of falcata germplasm for use in California is to screen cultivars from across the country for local suitability. Nitrogen fixation services, forage production, pollinator services, protection from erosion, and weed suppression may be benefits that falcata alfalfa cover could provide to agricultural systems in the Central Valley.
DH Putnam Scholarship Funding
DEVELOPMENT OF ALFALFA FOR A WATER CHALLENGED FUTURE submitted by Charles Janssen, Graduate Group in Horticulture and Agronomy, UC Davis
Summary: Based on future climate models, alfalfa growers in California will likely be unable to irrigate their crop fully throughout the growing season. One way to decrease water use is through deficit irrigation, in which no irrigation is applied for part of the growing season. Our research aims to determine how much water can be conserved by deficit irrigation and whether certain alfalfa varieties are better suited for summer deficit irrigation while still maintaining yield potential and stand survival once irrigation is resumed. We have established yield trials in Davis and El Centro, CA under both deficit and full-season irrigation. Each trial contains multiple paired UC experimental cultivars selected under deficit and full irrigation, improved experimental lines from New Mexico State University selected under water limitation , as well as already released and experimental varieties from private seed companies. We aim to identify cultivars well suited to deficit irrigation and make recommendations to growers regarding the best cultivars for both full and deficit irrigation managements.
DEVELOPING ALFALFA CULTIVARS FOR RAINFED RANGELANDS IN NORTHERN CALIFORNIA submitted by Cree King, Graduate Group in Horticulture and Agronomy, UC Davis
Summary: This plant breeding project aims to improve alfalfa for rainfed rangeland systems in Northern California. It includes evaluating the survival and persistence of current alfalfa varieties in grazed rangelands often experiencing drought conditions, as well as the incorporation of a “creeping-rooted” trait into non-dormant alfalfa cultivars to enhance stand persistence and biomass yield in rangelands. From these experiments, desirable plants will be selected and intercrossed to create improved populations with grazing tolerance, creeping rootedness, and increased winter productivity. Ultimately, we want to develop alfalfa varieties that are adapted to rainfed systems, which in turn can help to increase the productivity of California’s rangelands.
In 2023, the Foundation funded its fourth round of research projects. A synopsis of the research project selected by the Foundation is provided below.
TESTING YIELD AND ADAPTATION OF IMPROVED ALFALFA CULTIVARS FOR DROUGHT SCENARIOS submitted by Daniel H. Putnam, University of California Davis, Davis
Summary: In spite of the record snowfall and rains in 2022-23, drought years remain a severe challenge to alfalfa growers in California. In addition, the Sustainable Groundwater Management Act (SGMA) will restrict groundwater supplies, especially in the San Joaquin Valley, necessitating reduced irrigation for alfalfa. Based on past experience and future climate models, we expect alfalfa farmers will be unable to irrigate their crops fully in a large percentage (>50%) of future years. New varieties that thrive under these stress conditions are needed. Consequently, alfalfa cultivars that tolerate drought from irrigation cut off for portions of a year, yet still maintain multi-year persistence, high yield, and high quality. Alfalfa is a crop well suited to partial-season dry-downs, and will produce impressive partial-season yields when water is cut off, conserving 30-50% of the irrigation water normally needed. The question is: do we have varieties well suited to this scenario? This funding implements field trials at El Centro and Davis which tests commercial and experimental alfalfa varieties under both full irrigation and partial season drought. Some UC experimental lines were selected under late-season drought or dryland production, and improved lines for NM State University and private companies selected under drought will be tested.
In 2022, the Foundation funded its third round of research projects. A synopsis of the two research projects selected by the Foundation is provided below.
ONE SIZE DOES NOT FIT ALL: THE NEED TO ESTABLISH NEW TREATMENT AND INTEGRATED PEST MANAGEMENT THRESHOLDS FOR BLUE ALFALFA APHIDS (YEAR 2) submitted by Michael D. Rethwisch, UCCE, Riverside County, Blythe
Summary: Currently existing UCCE economic and treatment thresholds for blue alfalfa aphids in California alfalfa were developed when insect pressures were currently less than those recently documented and insecticides were fully systemic, compared with many newer insecticides are which are only acropetally systemic, and when alfalfa prices were much lower than currently being noted. Cowpea aphids are now also major pests in California low desert alfalfa and interactions and integrated pest management (such as ladybeetles) for control from one pest (cowpea aphids) to the next (blue alfalfa aphids) needs investigation, as yellowed alfalfa from cowpea aphid feeding is thought to be more attractive to blue alfalfa aphids migrating into alfalfa fields. This project year proposes continued comparative evaluation of current and potential new insecticides applied at various crop heights to document their efficacy in controlling blue alfalfa aphid, with data to be collected on alfalfa yield, quality and economic values to develop pest management decision tools and treatment/ economic thresholds for California alfalfa growers and pest control advisors on both established and first year alfalfa stands as 2022 data indicate large differences in insecticide efficacy results (which is not included in current thresholds).
EVALUATION OF ALMOND HULL APPLICATION AS A SOIL AMENDMENT TO ALFALFA STANDS submitted by Sarah Light, UCCE Sutter, Yuba, and Colusa Counties, and Rachael Long, Agronomy and Pest Management Advisor, Yolo, Solano, and Sacramento Counties
Summary: Last year, 4-8 tons/ac almond shells were applied to replicated research plots in a three-year old alfalfa stand and data collected on soil health, weed suppression, and alfalfa performance. The 8-ton per acre covering gives a uniform half to one inch covering of shells, which appear to suppress weeds in preliminary visual observations, and which we speculate may contribute to increased soil moisture retention. In year two, more almond shells will be applied to the same replicated field plots (within 6-months the shells assimilated into the soil) and the multi-year impact of almond shell application on the alfalfa stand, weed suppression, and soil health (including moisture retention and compaction) will be measured.
In 2021, the Foundation funded its seconded round of research projects. A synopsis of the two research projects selected by the Foundation is provided below.
ONE SIZE DOES NOT FIT ALL: THE NEED TO ESTABLISH NEW TREATMENT AND INTEGRATED PEST MANAGEMENT THRESHOLDS FOR BLUE ALFALFA APHIDS submitted by Michael D. Rethwisch, UCCE, Riverside County, Blythe and Thomas Getts, UCCE, Lassen County, Susanville, CA
Summary: Populations levels and damage by blue alfalfa aphids have become more damaging in California over the past decade, resulting in significant yield loss in the low desert and often crop death in intermountain regions. Many newer insecticides are only acropetally systemic (they only move to new leaf growth) and do not control aphids below the upper canopy. As such plant/stem height at time of application becomes extremely important for insecticide efficacy which differs by product and rate. This project proposes to evaluate and compare various current and potential new insecticides applied at various specific crop heights to document their efficacy in controlling blue alfalfa aphid. Additionally, information on alfalfa yield, quality and economic values will be collected to provide pest management decision tools and treatment/economic thresholds for California alfalfa growers and Pest Control Advisors (PCAs).
EVALUATION OF ALMOND HULL APPLICATION AS A SOIL AMENDMENT TO ALFALFA STANDS submitted by Sarah Light, UCCE Sutter, Yuba, and Colusa Counties
Summary: California growers are adopting innovative strategies to increase soil carbon and recycle agricultural by-products onto production farmland. Some producers have begun to adopt the practice of adding almond shells and hulls from nearby orchards onto alfalfa fields, however the benefits of this practice to the alfalfa stand have not been quantified. This project aims to measure changes in soil health and alfalfa yield for fields with and without almond hull application.
In 2018, the Foundation funded its first round of research projects. A synopsis of the three research projects selected by the Foundation is provided below.
EVALUATION OF WEED MANAGEMENT IN CONVENTIONAL SEEDLING ALFALFA submitted by Mariano Galla, UCCE Agronomy & Weed Science, Butte and Tehama Counties
Summary: Seedling alfalfa is especially susceptible to weed interference as interspecific competition can inhibit alfalfa growth and development compromising stand persistence. Poor weed control in seedling alfalfa can influence the size of future weed infestations through contributions to the soil seedbank thereby necessitating additional control measures. The research will evaluate the efficacy and safety of herbicides for the management of weeds in establishing stands. Because alfalfa is grown across a variety of environments within the state, concurrent trials will be conducted in the low desert, the San Joaquin and Sacramento Valleys, and the Intermountain area to generate up-to-date performance data specific to major growing areas.
EVALUATION OF WEED MANAGEMENT IN ESTABLISHED ALFALFA submitted by Thomas Getts, UCCE Weed Ecology and Cropping Systems Advisor – Lassen, Modoc, Plumas and Sierra Counties
Summary: Weeds are a significant concern in established alfalfa stands because weed infestation can reduce hay yields. Hay quality can also be influenced by weeds, because of palatability, nutrition, or toxicity concerns. Weeds can interfere with the cutting, curing, and baling processes, or they can trigger load rejections (i.e. noxious weed contamination). Local and export dairy markets pay growers a premium for weed free high-quality hay, whereas hay contaminated with weeds will be worth far less per ton. Weed control in alfalfa is imperative to economical production. The objective of the study is to evaluate the efficacy and safety of herbicides for weed management in established alfalfa fields. Because alfalfa is grown across a variety of environments within the state, concurrent trials will be conducted in the low desert, the San Joaquin and Sacramento Valleys, and the Intermountain Area to generate up-to-date performance data specific to the major growing regions.
REDUCING WEED PRESSURE DURING STAND ESTABLISHMENT USING PRE-PLANT WEED GERMINATION FOLLOWED BY MECHANICAL OR CHEMICAL CONTROL submitted by Sarah Light, UCCE Agronomy Advisor, Sutter, Yuba and Colusa Counties
Summary: Despite evidence that allowing weeds to germinate, and then controlling them prior to planting alfalfa is effective for reducing weed pressure during stand establishment, this practice is not widely used in the Sacramento Valley. This project will evaluate the use of a sterile seed bed, followed by either mechanical or chemical control, to reduce weed pressure during alfalfa establishment in the region. The cost of implementing both control methods will be quantified to enable the clientele to make informed management decisions on their farms.