EVALUATION OF COMPOSTED POULTRY MANURE ON PLANT HEALTH OF PROCESSING TOMATOES IN THE LOWER SACRAMENTO VALLEY OF CALIFORNIA

Composted poultry manure was evaluated as a surface-applied, shallowly-incorporated soil treatment prior to planting processing tomatoes. Two commercial fields per year were selected over a three-year period from 2011 to 2013. All evaluations were conducted within a single cropping season without repeat applications or measurement in succeeding years. Sites were chosen with a history of premature vine decline associated with loss of vigor and fruit canopy cover at the early fruit ripening, crop-growth stage. In all locations, treatments included pre-plant-incorporation of well-aged, composted poultry manure at 22 MT/ha. All treatments were supplemental to the grower fertilizer program with generally robust nitrogen and phosphorus applications to support high production. Disease incidence was assessed periodically and samples were processed in the lab to determine the disease-causing organisms. At several sites, Verticillium wilt was widespread. At a few sites, Fusarium wilt as well as Fusarium crown and root rot were common. Yields were generally increased in the plots with shallowly incorporated chicken manure while the incidence of disease was generally not affected by any treatment. Marketable yield increases to compost in select fields averaged 31 MT/ha. On a percentage basis, the yield increases were equivalent to 32, 41 and 25% in 2011, 2012 and 2013, respectively. As a result of the yield response to composted manure, later tests included supplemental applications of manufactured NPK at similar rates and placement to mimic nutrients in the composted manure treatment. The results indicate yield increases may occur in soils with potassium levels below 180 ppm using an ammonium acetate extraction method and with potassium levels not exceeding 2% on the cation exchange capacity.