How We Grow

2021 July/Aug How We Grow

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gases) from the soil between the various treatments," Edalati said. As the Dr. Zhang-led team nears the completion of its second year of research, various compost treatments have been applied to the test orchard and in-field measurements continue. The year two harvest is planned for August or September later this year, to be followed by additional measurements and a research update provided to the almond and dairy industries via ABC and CDRF. Additional research indicates positive impact of compost Another ABC-funded research project 2 indicates that dairy manure compost may be a viable option for supplementing – or even partially substituting – synthetic fertilizers in almond orchards. Since 2016, Dr. Sat Darshan S. Khalsa of UC Davis has led a research project to determine the effects of an annual application of four dry tons per acre of composted dairy manure on an almond orchard. "Compost tends to have a low non-organic nitrogen content, but a high organic nitrogen content, which takes time to decompose and become available," Dr. Khalsa said. "We saw that 70-80% of the compost visibly broke down on the surface, translating to 5-10% nitrogen availability for the growing season." Dr. Khalsa notes that one would naturally wonder what happened to the rest of the nitrogen in the compost: If only a small fraction of the compost's nitrogen is available for the growing season, does the vast majority leach through the root zone and potentially into groundwater? "We showed that the nitrogen from compost isn't leaching," Dr. Khalsa said. "Rather, the nitrogen is building up in the soil organic matter like an investment for future use." This investment may lead to growers being able to reduce applications of synthetic nitrogen by up to 20%, according to Dr. Khalsa. Dr. Khalsa's review of soil moisture samples from orchards that received dairy manure compost versus those that didn't also showed higher levels of soil moisture in the top 10 centimeters of the soil profile down to about 50 centimeters of soil depth, indicating improved water holding capacity in the root zone due to the buildup of soil organic material. Measurements of stem water potential also revealed that trees experienced lower stress where soil moisture content was higher in the root zone. 3 ABC's Huang notes that research projects such as Dr. Khalsa's and Dr. Zhang's are part of the organization's continued effort to assist growers in improving their operations both economically and agronomically. "We are excited about these research projects and their potential to unlock new and innovative ways to move the almond community forward," Huang said. "We look forward to updating growers and handlers as more results become available." Get to Know Your Board – Part Eight In the July/August 2019 issue of How We Grow, we published Part One of our series "Get to Know Your Board." In this series, we're profiling members and alternates of the Almond Board of California (ABC) Board of Directors, which is composed of ten members — five growers and five handlers — with each member having one alternate. This group of individuals embraces the California almond story and is living it every day, just like you. Read Part Eight of this series below, which highlights two industry members who serve as alternates on ABC's Board of Directors. When did you first become involved in the California almond industry? Caleb: I was born and raised on an almond and poultry ranch in Central California. After graduating from UC San Diego with a B.A. in Economics, I worked as a commercial and agribusiness relationship manager for nearly 10 years and farmed almonds on the side. In 2013, I left my banking career to farm full-time. In 2016, I was elected to the Board of Directors. Mark: Eleven years ago, I brought my wife, three kids, and our dog to California to lead Blue Diamond Growers. One of the first things I did was learn the difference between a grove and an orchard when one of our kind growers reminded me that "peaches, not almonds, grow in groves." I quickly came up to speed to overcome my naivety, and we've had a wonderful partnership ever since. ALMOND COMMUNITY Continued from page 16 ZERO WASTE 2025 GOAL Compost sourced from dairy manure is surface applied in strips around almond trees. 2 "Effect of Partial Fertilizer Substitution with Organic Matter Amendments on Nutrient Cycling," Almond Board of California 2020 Research Update: 3 "Impact of Organic Matter Amendments on Soil and Tree Water Status in a California Orchard" Lepsch H, et al. (2019) Agricultural Water Management: 17

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