It has taken some time for tree nut growers to become more receptive to implementing a cover crop system in their orchards. The practice has been shown to provide a series of benefits related to soil structure, bee health, and weed pressures. Crop Consultant with California Ag Solutions, Cary Crum said he has been working with a walnut grower in Hanford using flood irrigation. After having issues with water infiltration, Crum explained that the cover cropping system they have implemented is proving to be beneficial.
“We started working with him in implementing a cover cropping system to help open up the soil and provide better aggregate stability and improve overall water infiltration and ultimately reduce sodium accumulation. So that’s what we’re doing there, this is our second season,” Crum noted. “We came back at it with a more aggressive cover crop for this season that we planted directly after harvest.”
Growers have been somewhat hesitant to adopt cover cropping for a variety of reasons. Water use and maintenance have been concerns for growers, along with potential impacts the practice may have on harvest. Crum said that having a solid termination strategy and mowing protocol will alleviate any potential impact on harvest. Growers will, however, want to weigh the costs of a cover crop system with the benefits that it can provide, which can include significant yield increases.
TAKING THE NEXT STEP WITH COVER CROPPING
Once a grower has adopted cover cropping and has experienced success with the practice, Crum said there is another component that can be added. Implementing animal grazing into a cover crop system can amplify the benefits to microbial communities in the soil. Crum said growers can be apprehensive about integrating animal agriculture, but the practice does work really well.
“When you can implement animal integration into that cover crop system, you can really ramp up the biology in the soil. There’s some process that happens when you take the biomass that’s grown on that particular site and process it through the animals’ rumen and they extract both feces and urine and put it back on the soil,” said Crum. “Something happens in that process. The urine actually becomes like a biostimulant for the microbial community that’s there, but it’s actually been specifically designed for that community. So, it really ramps up that process.”