Soil characteristics, soil types, and nutrient management of the 13 organic tomato fields studied in Yolo County, California, USA.

Table is adapted from Bowles et al. (2014).a Based on measured sand, silt, and clay content in 0–15 cm surface soil (Bowles et al. 2014).b Tehama loam: fine-silty, mixed, superactive, thermic Typic Haploxeralfs; Capay silty clay: fine, smectitic, thermic Typic Haploxererts; Brentwood silty clay loam: fine, smectitic, thermic Typic Haploxerepts; Yolo silt loam: fine-silty, mixed, superactive, nonacid, thermic Mollic Xerofluvents.c Compost and manure were applied in fall 2010, with the exception of field 5, in which manure was applied in early spring prior to tomato transplanting. Winter vetch cover crops were incorporated prior to transplanting. Compost was composted yard waste with a C:N ratio ranging from 15–18. Manure was poultry manure or poultry litter with a C:N ratio ranging from 9.8–15.d Secondary nutrient inputs are generally applied as a sidedressing or through drip line during the growing season. Guano refers to seabird guano (12-12-2.5). Pellets were pelletized poultry manure (6-3-2). Chilean nitrate (16-0-0) is NaNO3, a mined mineral product. Soluble refers to solubilized organic fertilizers, especially fish emulsions, which have range of nutrient concentrations.e Approximate quantities of N added through compost, manure, secondary organic fertilizers, and vetch cover crops were estimated based on farmers' reported application rates and analysis of material or based on farmers' testing records. On several fields, data were not available for every input, so these rates are considered not estimable (n.e.).Soil characteristics, soil types, and nutrient management of the 13 organic tomato fields studied in Yolo County, California, USA.