Assessing Efficiency and Economics of Different Sources of Phosphorus in Alkaline Calcareous Soils for Wheat Production

Phosphorus (P) is an essential nutrient needed for plant growth, root development and grain production. Application of humic acid (HA) is considered to improve the plant growth and enhances stress tolerance. The decrease in amount of arable land and hiking prices of chemical fertilizers are a huge challenge for farmers. The prices of phosphatic fertilizers, especially the diammonium phosphates (DAP) urge the need to explore the cheaper sources of P. Therefore a three year field study was conducted to compare the efficiency and economics of phosphoric acid (PA) with two other traditional sources of P viz. single super phosphate (SSP) and DAP for optimum wheat grain production. Six treatments applied were Viz. Control, recommended dose (RD) of P from SSP, RD of P from DAP, RD of P from phosphoric acid (PA), RD of P from SSP + HA, RD of P from DAP + HA. These P fertilizers were applied at the recommended rates for wheat (90 kg ha-1) from SSP, DAP and PA. HA was also applied at the rate of 15 kg ha-1. PA was applied at first irrigation of wheat crop. The experiment was conducted at Soil Chemistry Section, ISC&ES, Faisalabad, Pakistan, using RCBD with three repeats during (2011-14). Basic soil analysis showed that the field was free from salinity and sodicity hazards with low organic matter status while available P was in the range of low to marginal and extractable K was adequate. Maximum grain yield (4.98 t ha-1) was obtained with the use of DAP fertilizer. The Cost Benefit Ratio (CBR) of DAP (3.0) proved it as most profitable P fertilizer with the maximum benefit return. Further the fertigation of PA did not proved better in terms of CBR while the application of HA with SSP and DAP significantly lowered the CBR.