Physical Soil Health and Water Storage Dynamics of a Novel, Perennial Cover Crop in California Almond Orchards

Project Overview

Project Type: Graduate Student
Funds awarded in 2024: $29,984.00
Projected End Date: 12/31/2026
Grant Recipient: University of California, Davis
Region: Western
State: California
Graduate Student:
Principal Investigator:
Dr. Mallika Nocco
University of California, Davis
Principal Investigator:
Dr. Cristina Lazcano
University of California Davis


  • Nuts: almonds


  • Crop Production: cover crops
  • Education and Training: demonstration, extension, on-farm/ranch research, technical assistance
  • Natural Resources/Environment: carbon sequestration, soil stabilization
  • Soil Management: organic matter, soil physics, soil quality/health

    Proposal abstract:

    Cover cropping has been
    demonstrated to be an effective conservation technique at
    combating soil degradation and restoring soil health.
    Unfortunately, California orchard growers have low rates of cover
    cropping due to management timing, costs, and concerns of
    competition with crops for resources, especially water. A
    hybridized cool season grass, Radix
    Poa bulbosa, commonly referred to as Oakville Bluegrass,
    presents a novel drought-tolerant, perennial cover crop designed
    for orchard systems. The project team will partner with working
    almond orchards in the California Central Valley to assess the
    impact of Oakville Bluegrass on a suite of physical and
    hydrologic soil properties during cover crop establishment. This
    research will address if the novel cover crop can bring
    improvements to water storage dynamics through structural changes
    and carbon inputs. Continuous soil moisture data will be
    collected in addition to water use efficiency of orchard trees to
    clarify perceptions of cover crop water use, addressing concerns
    that often lead orchard growers to maintain bare ground
    management. Collaborating almond growers will document
    operational changes linked to managing the cover crop. Field
    days, hosted on participating orchards, will showcase the soil
    health impacts of cover cropping with Oakville Bluegrass and
    offer technical assistance to growers. Research findings will be
    communicated through printed outreach materials and digital media
    in the form of a short video, blog, and podcast. This research
    aims to contribute to knowledge on soil health and water dynamics
    of perennial cover crops in semi arid, irrigated cropping systems
    of California.

    Project objectives from proposal:

    Research Objectives: 

    1. Evaluate the impact of
      perennial cover cropping on structural and hydrologic soil
      properties compared to bare ground management.
    2. Quantify changes in soil carbon
      pools from cover cropping and evaluate carbon inputs from cover
      crop biomass, ground coverage, and plant C:N. 
    3. Examine the effect of cover
      cropping on soil moisture and plant water response of almond

    Educational Objectives:

    1. Create outreach materials to
      increase knowledge and awareness of the effect of cover
      cropping on soil health through:

      1) a video showcasing soil management
      strategies using a rainfall simulator demonstration, and 2) an
      illustrated fact sheet about perennial cover cropping with
      Oakville Bluegrass.
    2. Demonstrate the soil health and
      management impacts of perennial cover cropping compared to bare
      ground management through two field days hosted at a
      participating producer’s orchard.
    3. Communicate findings through 1)
      co-creating an episode for the UC ANR Water Talk podcast, 2)
      presenting research at extension and grower conferences, and 3)
      publishing research in a peer-reviewed journal.
    Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the view of the U.S. Department of Agriculture or SARE.