Nitrogen mineralization rates of soils amended with nontraditional organicwastes

Nitrogen mineralization rate (NMR) studies provide a means to determine pla nt-available N resulting from organic waste applications. Nontraditional or ganic wastes (food processing and yard wastes) were applied at two differen t rates (112 kg N ha(-1) and 224 kg N ha(-1)) to soils from two different s oil series, Adelphia sandy clay loam (Aquic Hapludults) and Sassafras sandy loam (Typic Hapludults) in a 25-week laboratory incubation study. Suppleme ntal ammonium sulfate was added to the soils amended with wastes with high C/N ratios. Nitrogen mineralization rates were reported as the percent orga nic N mineralized from organic waste. The NMR ranges for the vegetable food processing wastes were 13.9 to 55.1% (Adelphia soil) and 17.0 to 66.8% (Sa ssafras soil); for the other food processing wastes: -20.8 to 39.9% (Adelph ia soil) and -20.5 to 47.7% (Sassafras soil); acid for the yard wastes: -26 .7 to 29.8% (Adelphia soil) and -22.6 to 65.6% (Sassafras soil). The applic ation rates of the wastes and the two soil types affected the NMRs of sever al of the organic wastes studied significantly (P < 0.05), The effect of wa ste characteristics and soil type on NMRs needs to be accounted for if orga nic wastes are to be used as a N source. One option is to apply organic was tes at rates below agronomic recommendation rates, based on NMRs, and to su pply additional inorganic N as needed. (Soil Science 2001;166: 353-363).