Comparison of nitrophosphates in affecting sorption, desorption and availability of phosphorus in an inceptisol under long-term wheat-maize cropping system

摘要

A long-term field experiment was started in rabi of 1994 at PAU research farm, Ludhiana, Punjab, India, using wheat-maize cropping system on Typic Haplustept loamy sand. Three different water-soluble P fertilizers: diammonium phosphate (DAP) and two nitrophosphates (ANP and suphala), were applied at two rates (0 and 80 kg P2O5/ha) to wheat crop and the succeeding (maize) crop was raised on residual P. Surface (0-15 cm) soil samples were collected in 2000 (sixth cycle of wheat-maize rotation) after the harvest of each crop to study P sorption, desorption and available P status of the soil. The results revealed that ANP and suphala were statistically at par with DAP for P sorption, desorption, available P, yield and P uptake. This suggested that nitrophosphates can be used as potential P fertilizer substitutes for DAP. Highly significant correlation coefficient values between various sorption and desorption parameters and yield, P uptake and available p status of soil after sixth cycle of wheat-maize rotation indicated that the inclusion of sorption and desorption parameters in any of the P fertilizer recommendation approaches can help increase the accuracy of P fertilizer recommendations and hence, the P fertilizer use efficiency..