Almond Series #2

This is a continuation of the trial we established in 2019 on a California almond farm in the process of transitioning to regenerative. The grower wanted to change some of the trial locations and treatments based on successes and failures from the previous season. We also decided to involve another grower in the trial. His orchards are reflected in Treatment E. The 2020 treatment programs are below:

Results: 

The 100% organic treatment A, with high amounts of compost (10 tons/acre) and Provide and Revive, was the most effective in improving soil and tree health from soil samples of biology and nutrients.However, yields were low due to a handful of problems including cover crops taking Nitrogen from the trees, poor weed management, and leaf burn from a high rate of fish fertilizer and copper foliar spray. 

With no NPK fertilizer for Treatment A, 70% reduced NPK rates for Treatment B, and 50% reduced rates for Treatment D, these treatment areas had noticeably increased nutrient use efficiency. Treatment C, which did not include Provide and Revive but rather worm tea extract, resulted in poor biological performance and yield losses. 

Treatments B, C, and D were significantly cheaper per acre than the old conventional program. Treatment A was more expensive because of the high amount of compost applied, and treatment E was more expensive because the NPK inputs were at 100% rates. 

Provide and Revive treatments A, B, & D had improved water holding capacity. We measured plant stress and irrigation schedules by Phytech dendrometors and visual observation. During deficit irrigation, the Provide/Revive treated blocks’ deficit rates were increased from 15% to 60% more than the typical grower standard without any additional stress to the trees. “The average deficit rate increase on the Provide/Revive treatments [A-D] was 30%.” Furthermore, 2nd leaf trees in the Treatment D block showed no stress in the dendrometer for 21 days without irrigation, while 2nd leaf trees on an adjacent field without Provide and Revive only lasted 7 days without irrigation before showing stress.  

Treatment E showed no difference in biology, plant health or yield. This may be due to the fact that these orchards were in their first year of treatment, whereas the other four treatment areas were in their second year. It can take time for the biology to work its way back in a previously intensive conventional system.  

Our 2020 data for this trial showed that reducing your chemical treatments and adding biology can result in improvements in water holding capacity, reduced plant stress, and improved disease and pest control. Plus, these changes are cheaper than the conventional program. 

Our work with these growers is ongoing and we will continue to collect more data as the season progresses.