Use of Cover Crop Mulches in a Processing Tomato Production System

Abstract

Conventional processing tomato production in California relies on inputs of synthetic fertilizers, water, and tillage to achieve high yields. Recently, there has been interest in reducing off-farm inputs and increasing soil quality by reducing tillage and increasing organic matter. Thus, this experiment examined the use of cover crops and no-till tomato production. Experiments were conducted in 1996 and 1997 at two sites, Five Points and Davis, Calif. Winter-grown cover crops included barrel medics, subterranean clover, pea, vetch, triticale, ryegrass, oat, and fallow controls. Cover crop plots were divided into three parts and nitrogen fertilizer added at 0, 112 or 225 kg/ha. Cover crops were mowed, and 3 weeks later, tomatoes were no-till transplanted into each plot. Weed cover at all sampling dates was less than 5% on all plots at the Five Points site, with no significant differences among treatments. At Davis, weed cover was much higher, but was also not significant among treatments. Tomato yields were highest (93 ton/ha) on the fallow plots and lowest (58 ton/ha) on the barrel medic plots at the Five Points site. At Davis, tomato yields were generally very low due to competition from weeds. The barrel medic cover crops plots had the highest tomato yields at this site (34 tons/ha), with plots without cover crops having the lowest yields (12 tons/ha). Tomato yields were 18% and 29% higher when 112 kg/ha or 225 kg/ha of nitrogen was added, compared to no nitrogen.