EVALUATION OF PHOSPHORUS EFFICIENCY IN SOYBEAN (GLYCINE-MAX) AND WHEAT (TRITICUM-AESTIVUM) CROPPING SYSTEM IN RELATION TO FERTILIZER ON A TYPIC HAPLUSTERT

In a field experiment in a semi-arid climate on a Typic Haplustert, se veral means of measuring phosphorus efficiency were evaluated in soybe an [Glycine max (L.) Merr.]-wheat (Triticum aestivum L. emend. Fiori & Paol.) cropping system in relation to applied P. Seven rates of P (0, 10, 20, 40, 60, 80 and 100 kg P/ha) were applied to both the crops. T he computed optimum fertilizer P rates to achieve 90% of the maximum y ield were 32.5 to 33.5 kg P/ha for soybean and 49.5 to 44.5 kg P/ha fo r wheat during the 2 years. More applied P was translocated to grain i n wheat tan in soybean. The efficiency of fertilizer - utilization in both the crops was reduced beyond 40 kg P/ha. Wheat proved more effici ent in utilizing the fertilizer P and also required larger dose of fer tilizer P, whereas soybean efficiently utilized the soil P and require d lower rate of the fertilizer P.