About 40 farmers on Tuesday got a message from the underground: Take care of the soil as far down as the roots reach.
They gathered at a farm just south of Turlock to see how “deep ripping” can improve the soil structure and how compost can help it retain water and nutrients.
“Trees are going to love growing in this,” said Paul Borges of B&B Ag Consulting in Modesto, speaking from the bottom of a 4-foot-deep pit that had been dug for the occasion. The vertical walls showed healthy soil layers, he said.
The East Stanislaus Resource Conservation District hosted the event on an 8-acre site where owner Chet Prohaska is about to plant almond trees. The ideas also could work on walnut and fruit trees and grapevines.
Deep ripping by tractors breaks up large chunks of soil to improve the penetration of roots, water and nutrients. Most of the San Joaquin Valley does not need the treatment because of naturally good soil structure, but it helps with the hardpan that lies just under the surface in some places.
Compost is made from landscape trimmings, food scraps and other organic material, transformed by microbes in small backyard piles or industrial-scale operations. Tuesday’s event involved compost from Recology, which is based in San Francisco and makes some of its product near Vernalis.
Compost reduces the demand for irrigation water, a concern in what looks like a fourth year of drought, said Jorge Alvarado, watershed coordinator for the conservation district.
Compost also helps the soil hold nutrients, he said. This could be especially valuable with nitrogen, which transforms into nitrates, suspected of tainting groundwater in some areas.
Compost has a distinctive black color and fluffy texture. Alvarado said about 20 tons are typically applied per acre, but it can be as little as 5 tons if it is concentrated at the tree roots. The material can be used on mature orchards and vineyards, as well as new plantings.
Darrell Cordoza has used deep ripping and compost on his almonds and walnuts east of Denair.
“It gives the young trees a chance to really grow and develop,” he said. “With the compost, you’re building the soil, and that’s key.”
Bee staff writer John Holland can be reached at email@example.com or (209) 578-2385.