Farm Information

County: Colusa
Location: Sacramento River
Slope: Flat
Irrigation system: Micro-sprinklers: mix of solid set and aboveground hose
Soil type: Sandy loam
Soil detail: n/a
Special farming challenges: Gophers

• Cropping Systems Information
• Crop: walnuts
  Acres of orchard or vineyard: 112

  Other crops: no
  Acres of other crops: n/a
  Organic management: Yes
  Certifications: Yolo Organic
  Certifications notes: In the certification process. 30 acres now certified with new blocks transitioning each year, all will be certified organic by 2023, except for 35 acres
  Where using cover crops: Walnuts

• Grower Experience, Farm Priorities, and Cover Cropping Goals
• When started farming (yr): 1977. They started farming organic vegetables and flowers. Bought this property in 2005.
  Farm priorities: Committed to ecological, organic farming. Finds it easier, and doesn’t like dealing with chemicals and their effects on the farm’s ecosystem.
  Years growing orchard or vineyard crop: 16 years
  Years growing cover crops: 13 years
  Initial transition to cover cropping: Worked with NRCS conservation plan starting in 2008, using a soil builder mix to increase available nitrogen.
  Goals and benefits: Nitrogen supplement, soil improvement, insect predator support, pollinator support
  Benefits description: Nitrogen fixation, soil organic matter, pest control, beneficial habititat
  Change in goals over time: Now, trying different cover crops to increase biomass and soil organic matter, address nematode issues, and move to more permanent cover.
  Reasons: Included mustards and tillage radish for nematode suppression starting two years ago. And this year, they are including the mustards and radishes with soil builder mix across the farm to address any emergent issues with nematodes in other blocks. Also, next year they will plant cover crops only in alternating rows to allow orchard access in every other row during winter pruning.
• Cover Crop Details, Planting and Management Methods

• Block described here: Walnuts: Certified Organic
  Current cover crops: Legumes, grasses, brassicas
  Species and mixes: Legume dominant mix (bell beans, peas, clover, vetch), triticale, other grasses`
  Planting method: Broadcast seed
  Planting date (2020): Early November
  Was that optimal? Yes, following the walnut harvest closely is ideal.
  Pre-plant soil prep: After harvest, irrigate then lightly disc. Broadcast seeds, then disc again with a roller followed by another light irrigation depending on rain.
  Planting equipment: PTO-driven broadcast seeder, disc to cover
  Seeding rate: 60 lbs/acre
  Seeding depth: n/a
  Did it germinate well? Okay
  Additional management and advice: May move to planting every other row for orchard entry and pruning in the winter as a trial. Will also give them the opportunity to apply spring compost application earlier on rows that don't have the cover crop in.

• Cover Crop Termination Methods and Biomass Management

• Termination method: Mow
  Termination equipment and process: Flail mower for all except cover crop that drifted in-row to the strips. Weed eater with a blade for the strips.
  Termination date: Early April
  Was it optimal? n/a
  Biomass management: Left in place what remained after chopping with the flail mower. Otherwise, what is the point of cover cropping?

• Cover Cropping Challenges and Strategies to Address Them
• Challenges: Vertebrate pests
  Challenges description: Gophers
  Strategies to address challenges: In organic system, not many options. Has barn owl boxes but less effective with cover crops.
  Was the cover crop worth it? Yes, they have seen good results after 3 years. healthier trees, good growth not seen for years. They find it to be a cost-effective option for adding nitrogen in an organic system. Also add compost, but that is much more expensive. Still unsure of the nematode benefits, not clear in the soil tests.
  Least successful past cover crops: n/a