IMPROVING PHOSPHORUS USE EFFECIENCY AND ITS EFFECT ON THE PRODUCTIVITY OF SOME CROPS

Abstract

A field experiment was carried out in two successive seasons at El-Ismailia Agric. Res. Station, ARC, in El-Ismailia Governorate, Egypt, to study the efficiency use of two different sources of P fertilizer i.e. superphosphate (SP) versus rock phosphate (RP),both of them were used with three levels (0, 22 and 30 Kg P 2 O 5 fed-1), combined with two rates(20 & 30 L fed-1) of humic acid as K-humate sprayed over the surface soil layer, some chemical soil properties (soil pH, electrical conductivity (EC) ,OM and available N, P and K) were determined after corn and sesame harvesting. Yield components of both corn and sesame were, also, evaluation along with N, P, and K uptake by corn and sesame (straw, grains and /or seeds). Data revealed that the use of superphosphate (SP) and rock phosphate (RP) combined with humic acid increased slightly pH, EC and OM values in soil after corn and sesame harvesting. Also, EC in soil at both tested seasons, generally, had increased in presence of RP as compared to SP. Moreover, available N, P and K increased in soil along with the application of P-sources (SP & RP) combined with high rate of HA (30 L fed-1). Also, the application of super phosphate (SP) combined with humic acid (30 L fed-1) was superior as compared to rock phosphate (RP) at both tested soils after corn and sesame harvesting. Obtained data show that the use of 30kg P 2 O 5 from either superphosphate or rock phosphate combined with humic acid (30L fed-1) was superior for increasing the yield components and biological yield of both corn and sesame yields as compared to both control and the other tested treatments. In addition, the application of SP combined with humic acid had a significant positive effect on both corn and sesame yield components(straw, grains and /or seeds and biological yield) as compared to RP treatments. On the other hand , N, P and K uptake in straw, grains and /or seeds of both corn and sesame plants exhibited a positive significant trend along with the use of both P-sources as compared to the control treatment. Superphosphate increased significantly the uptake of N,P and K in straw and grains and/or seeds for both corn and sesame plants as compared to either rock phosphate or control treatment. Moreover, the calculated values of P-use efficiency by corn and sesame plants indicated that the presence of high rate of humic acid had enhanced the P-use efficiency of both tested crops, similar results was observed in both P-sources especially for superphosphate. The highest P-use efficiency was obtained with the use of high level from P (30 kg P 2 O 5) combined with high rate of humic acid (30L fed-1). P use efficiency increased by increasing the rate of humic acid at both tested P-sources. Keywords: super phosphate-rock phosphate-humic acid-P-use efficiency-corn-sesame-biological yield.