The basis of our farming system is simple: to enhance and work with what is already there. Over a decade ago, during a presentation by University of California Cooperative Extension (UCCE) specialist Walt Bentley, a comment was often repeated that many natural predators and parasites exist in walnut orchards. According to Bentley, farmers simply need to make sure they don’t kill or harm them. Unfortunately, most people in the audience did not hear this. Russ did. After all, it fell in line with what Dixon Ridge Farms was already observing and doing.
At Dixon Ridge Farms, this simple idea, coupled with looking at the entire system, comprises what we do. We don’t just look at nitrogen; we look at fertility. We don’t just look at how cover crops can supply fertility; we look at how they can suppress weeds, conserve soil moisture, attract and keep beneficial insects, cool the orchard, and supply cover crop seed for next year. We don’t just look at soil as an inert mineral to hold roots and water; we view soil as a living, dynamic supplier of micronutrients, microorganisms, carbon, nutrients, water, minerals and the basic building blocks of life. And throughout our farming operation, we look at ways of maximizing our resources, minimizing our inputs, and by doing so, maximizing our net income, not our gross income.
Our Cover Crop: A “Rich Mix”
Our cover crop seed mixture is designed to help us achieve all of these goals and more, and at Dixon Ridge Farms, it is the heart of our farming system. Our “Rich Mix” is comprised of Lana (wooly pod) vetch, purple vetch, common vetch, crimson clover, sub-clover, burr medic, oats, cereal rye, and barley. This mixture is used in orchards where maximum biomass and nitrogen is desired and where water is available to 100% of the soil surface via irrigation. In orchards employing micro-sprinklers or drip lines, we use a variant, called micro-sprinkler mix, which encourages earlier seed and nitrogen production as the majority of the soil surface dries out early. This mixture also produces less biomass, which can be hard to break down without irrigation, tillage or rainfall.
This cover crop grows during walnut tree dormancy when water use by the trees is very low. Topping methods have evolved to allow maximizing nitrogen production while minimizing weeds and water use. These toppings are timed to coincide with the times that the trees need nitrogen and water. Final mow down of the cover crop is delayed until after seed production occurs. This late mow also provides habitat for beneficials while creating mulch for water conservation and weed suppression. Mowing of the cover crop occurs early enough to allow decomposition prior to harvest. Harvest is done in a conventional manner, requiring bare ground, thus mowing and allowing for decomposition are a matter of great importance.
At harvest, our walnuts are picked up and placed in trailers. These trailers are labeled as to field of origin, lot and variety. Buffer rows are harvested, handled and labeled separately. These walnuts are transported to the huller where they are hulled, cleaned, washed and sorted. They are then placed in dryers, which are labeled the same way as the transport trailers. After drying, the walnuts are transferred to bins, which are similarly labeled. These bins are weighed, and a Certified Weight Certificate is issued. The bins are then placed in our storage facility.