jul-aug-2019

Figure 1. Average temperatures (degrees C) in the resident vegetation (left graph) and the cover cropped (right graph) treatments from the frost event occurring February 19, 2018. Temperatures were measured in the topsoil and at two inches, three feet, and five feet above ground (AB). Temperatures at five feet were nearly identical between cover cropped and resident vegetation treatments 2 . placed in orchards with or without cover crops. She also tracked the rate of survival of each colony throughout the year after they were done pollinating almonds. The results have significant positive implications for both the grower and beekeeper. The colonies pollinating almonds that had access to the PAm Mustard Mix had a 100 percent survival rate as compared to a survival range of 70 percent to 80 percent of colonies with access to later blooming cover crops or bare ground (no cover crop). Dr. Niño also found colonies that pollinated almonds with the PAm Mustard Mix cover crop were more populous by an average of three frames than colonies without access to cover crops 1 . The risk of frost damage is a concern some growers have when deciding whether to use cover crops. Preliminary results from a recent study on the effects of frost were intriguing and may help shed some light on the role cover crops play in orchard temperatures. Recent work from Dr. Dani Lightle, Cynthia Crézé, and Dr. Amélie Gaudin will also answer some important questions regarding how cover crops affect soil organic matter, water use, pest pressure, and greenhouse gas emissions. They found orchard floors with cover crops were cooler by a few degrees than those with bare ground or resident vegetation. However, at a height of five feet above ground the average temperatures of the orchard with a cover crop and without were the same 2 . Research into temperature dynamics is continuing. Project Apis m.’s Seeds for Bees ® continues to increase the acres of cover crops who growers and beekeepers are relying on to improve the health of their soil, trees, and bees. Last year we provided enough seed to plant more than 8,000 acres of cover crops. The 2019 – 2020 growing season Seeds for Bees ® open enrollment period is going on now. Interested applicants are encouraged to apply by going to the Project Apis m. Seeds for Bees ® website at www. projectapism.org/apply-to-enroll. We are currently accepting applications through November 1, or until we run out of seed. Growers of all types can apply and first-year applicants are awarded up to $2,000 of free seed. Keep in mind early planting is key to getting the most benefit as possible from your cover crop stand. Stay tuned for more results from the 11 scientists who are working hard to study what exactly is going on in your cover crops. Feel free to contact Billy Synk at billy @ projectapism.org for any questions regarding the Seeds for Bees ® program, cover crops, or bees/ pollination. References: 1 Nino, Elina, 2016 and 2017. Longitudinal Evaluation of Honey Bee Colonies on Different Forage Regimes. Almond Board of California Annual Research Reports 2 Lightle, D. Crézé, C. Gaudin, A. 2018. Cover Crops in Almonds: Research Updates. UCCE Tehama County Fruit and Nut Notes Article contributed by Project Apis m. 2 1 J U L Y – A U G U S T 2 0 1 9