Nitrification of Ammonium Sulphate and Urea in Soil as ffected by Salinity and Organic Matter Supplementation.

Abstract

A laboratory experiment was conducted to study the effect of diluted sea water on nitrification of ammonium sulphate and urea fertilizers in the absence or presence of organic matter. Increased salinity delayed, suppressed or inhibited nitrification of both fertilizers. Ammonification of urea seemed to be independent of salinity. Nitrification, generally, was sensitive to salinity. Addition of narrow C/N ratio organic matter (Berseem) enhanced ammonification and nitrification while wide C/N ratio ones (wheat straw) encouraged immobilization of mineral nitrogen. Supplementing fertilizer nitrogen with organic matter alleviated the adverse effect of salinity on nitrogen transformations in soil.