The Influence of Organic Wastes and Inorganic Nitrogen Sources on Soil Nitrogen, Yield, and Elemental Composition of Corn

Abstract

AbstractThis experiment evaluated the effect of synthetic N fertilizers, organic wastes, and fortified organic wastes on soil mineral and total N, crop yield, and elemental composition. Treatments consisted of equivalent rates of N (224 kg/ha) as NH4NO3, urea, sewage sludge, sewage sludge fortified with urea, leather tankage (LT), and organiform (leather tankage chemically fortified with urea‐formaldehyde). Corn (Zea mays L., cv. ‘DeKalb XL‐394’) was used as an indicator crop and soil N measurements were conducted throughout the growing season.Soil levels of NH4‐N, NO4‐N, and total N indicated that the organic waste materials provided adequate amounts of available N for crop growth. Fortified and nonfortified wastes resulted in similar amounts of mineral and total N in the soil, indicating that fortification could reduce application problems associated with high loading rates of organic wastes. Accumulations of mineral N at the end of the corngrowing season suggest that the loading rates used in this study may have been excessive. While this excess available N would be beneficial for subsequent crops, it could also provide a source of contamination for surface and ground waters.Organic wastes consistently produced yields and plant tissue N levels equal to or greater than yields and N levels obtained with ammonium nitrate or urea. The treatments increased Zn in plant tissue and on plots receiving sewage sludge, and Mn and Cr accumulations in the tissue of plants grown on leather tankage treated plots. Except for the LT‐treated plots at the early growth stage, crop growth and yield were uninhibited.