California almond growers are examining new ways to deal with tree biomass produced by the removal of old orchards other than cogeneration burning. While sending the biomass to cogeneration converts the wood to electricity, returning the wood back to the soil would return the nutrients and energy back to the soil ecosystem.<\/p>\n
Thus, one concept getting closer attention is whole orchard recycling \u2013 grinding up entire almond orchards and incorporating the tree biomass into the soil, returning nutrients, improving the soil quality, and potentially sequestering the carbon contained in the wood chips.<\/p>\n
The potential benefits of whole orchard recycling on soil quality and subsequent trees replanted in that orchard have been the subject of Almond Board-funded research by Dr. Brent Holtz<\/a> of the UC Cooperative Extension Service in San Joaquin County and were discussed and demonstrated recently as a grower field day in the Central Valley.<\/p>\n Using a 50-ton \u201cIron Wolf\u201d rototiller capable of grinding standing whole trees and incorporating chips into the soil, peach trees in an old orchard were shredded and incorporated in a plot, with trees in another plot burned and the ashes spread on the soil surface. Almond trees planted in both plots were fertilized normally. By the third year, the nutrients were significantly greater where trees were ground up and incorporated into the soil. By the 6th<\/sup> year, the whole-orchard chip incorporation treatment resulted in increased organic matter, soil carbon storage, nutrients and microbial diversity, including beneficial fungi, as well as increased water-holding capacity of the soil.<\/p>\n