Since land is limited, increased productivity from existing land is urgently needed in achieving improved and sustainable agriculture in Bangladesh. Among several important measures, use of agro-chemicals to maintain soil fertility must be implemented. It is most important that environmental pollution through excessive fertiliser use must be avoided. The N is the vital of all major nutrients and its low inherent status in soil is probably the major cause of poor crop yields in the LEDCs. The N pool can be increased through fertiliser use; however, problems arise which are highly related to...