Field Experiment on Long-Term Application of Chemical Fertilizers and Farmyard Manure in Floodplain Soil of Bangladesh

Field experiment on long-term application of chemical fetrilizers and farmyard is ongoing in a floodplain soil of Bangladesh since 1978. The treatment are application of N, NP, NK, NPK, NS, NZn, NSZn, NPKSZn, and N+FYM (cowdung as farmyard manure), along with control (no addition), and have been executed in every cropping. Forty-five times of paddy rice cropping was done before soil sampling in Julu 2002. Among chamical properties of soil, the organic matter and total N concentrations, clay mineralogical composition, and the heavy metal concentration were asessed. The organic matter and total N concentrations of surface soil were increased from those in the initial state, although this was ascribed to continuous sropping of paddy-rice rather than the direct effect of chamical ertilizers and farmyard mature. Clay mineralogical change, such as fixation of H in the vermicutie interlayer to be transformed into clay mica, was not detected. Accumulation of heavy in soil was not noticed