EFFECT OF SODICITY ON THE UTILIZATION OF PHOSPHATIC FERTILIZERS BY WHEAT

We conducted a pot experiment to study the utilization of three phosphatic fertilizers (monocalcium phosphate, diammonium phosphate, nitrophosphate) at three levels of sodicity (0.2, 29.3, 50.2 ESP) by wheat (Triticum aestivum L.). Diammonium phosphate and monocalcium phosphate were on a par in alkaline nonsodic soil. At 29.3 ESP, diammonium phosphate was a better source of P than monocalcium phosphate, but at 50.2 ESP monocalcium phosphate outyielded diammonium phosphate. Nitrophosphate having 57.5% water-soluble phosphate was only 51.5% efficient, compared with diammonium phosphate. The utilization of P decreased with increasing level of P. At higher levels of P, wheat plants exhibited copper deficiency, and the concentration of P and Cu followed a log-log linear relationship.