Effects of inorganic and organic sources of nitrogen and potassium on physical and chemical properties of soil under rich cropping

摘要

A field experiment was conducted in an Old Brahmaputra Floodplain Soil at Bangladesh Agricultural University Farm, Mymensingh to see the effect of inorganic and organic sources of nitrogen and potassium on physical and chemical properties of soil under rice cropping (Var. BR11 rice). Two levels of nitrogen (50 and 100 kg N/ha) in combination with two levels of potassium (40 and 60 kg K_2O/ha) from each of inorganic and organic sources were used. Soil properties were monitored at the maximum tillering stage and after crop harvest. The inorganic sources were urea and MP for N and K, respectively, the respective organic sources being mustard oilcake and ash. Sixty kg P_2O_5/ha was applied as blanket dose from TSP. The addition of N and K from different sources did not exert significant effect on the physical properties of soil like bulk density, porosity and water holding capacity. Chemical properties like organic matter content, cation exchange capacity, total N, exchangeable K, avalilable P and Swere favorably influenced by the application of organic sources of nitrogen and potassium while the organic source mostly did not show positive effect, soil pH decreased slightly from the initial status.