Journal of the Indian Society of Soil Science

Quantitative relationship of fertilizer phosphorus requirements for black gram through two sources, viz., superphosphate and diammonium phosphate, with Olsen-P in soil and fertilizer phosphorus were established on the basis of parameters. viz., nutrient requirement, soil and fertilizer phosphorus efficiencies computed by three procedures, viz. conventional, model I and model II. The model II was found to be consistent in computing the efficiency parameters. The validity of these relationships based on all the three procedures were examined by conducting test verification trial. Since the percentage achievement of the aimed target in yield was highest wUh model II in both sources of phosphorus this model was considered to be superior to other two employed for computing soil and fertilizer nutrient efficiencies in the present investigation.