Researchers have been evaluating cover cropping in commercial almond orchards for the last three years, with interesting results. While there are still several questions about the practice that will need to be addressed, the growers who have been participating in the research have incrementally expanded their cover cropping systems and experienced various benefits from the practice.
“The most noticeable benefits have been in terms of an increase in infiltration of rainfall and irrigation water, winter weed control and decreasing compaction and increases in yields,” Amélie Gaudin, Assistant Professor of Agroecology at UC Davis. “We haven’t noticed any difficulties at harvest which is promising for adoption for this practice on a wider scale.”
Over the course of the research, a 12th leaf orchard with extremely compacted soil experienced a 200 pound per acre yield increase in year two of the trial. Gaudin noted that it was more an indirect result of the cover crop that was planted due to the soil compaction, but it still highlights the potential that cover crops present. Establishing a cover crop can also provide much-needed forage for pollinators, with the research indicating very little competition for pollination between the cover crop and the trees. “When you talk to beekeepers they do feel it at the end of the season with the strength of their hives being way better when they were in orchards that had some forage for bees during the pollination season,” Gaudin noted.
STILL WORK TO BE DONE
Some of the reservations about implementing cover crops in almond orchards come from concern surrounding harvest and maintaining a clean orchard floor. Gaudin noted that terminating the cover crop immediately after bloom in their experiments addressed the issue, however, there are still many questions that will need to be answered before cover crops become commonplace in almond orchards.
“Growers have a lot of questions of, what should I plant? Which mixture for which objectives? When should I plant? How do I terminate my cover crop? How do I keep it mowed? How to facilitate sanitation and frost control?” said Gaudin. “So, we need to get these fundamental best management practices out there in a format that is digestible for growers and their advisors and that’s something that we’ll be actively working on.”
Listen to the interview below.