16. Effect of acidulated levels and application techniques of rock phosphate on phosphorus use efficiency and yield of wheat in calcareous soil of Peshawar-Pakistan

Abstract

The present study investigated the effect of different levels of acidulated rock phosphate (RP), liquid or solid and application methods on phosphorus use efficiency and wheat yield under calcareous soils of Peshawar during 2015-16. Treatments included acidulation of 100 kg RP with 7.5, 15, 30 and 45 kg H₂SO₄ equivalent to 25, 50, 100 and 150 % acidulation, applied in the form of either liquid or solid as single (no split) or two equal splits at sowing and knee height stage. The rate of P in all treatment was equal to 90 kg P₂O₅ ha^-1. Our results showed that acidulation levels significantly increased wheat yield, post-harvest soil and plant tissue phosphorus optimum at 100 % acidulation level. Solid form of the acidulated RP was more effective than liquid revealing that lesser the contact of soil, could improve P availability from the source. It was further affirmed by the split application where it significantly increased the crop yield and P availability over no split irrespective of solid and liquid form. Our results suggest that solid RP with 100 % acidulation applied in two splits improved the crop yield, P use efficiency and could substitute commercial fertilizers under the prevailing soil and agro-climactic conditions.

Keywords: Acidulated rock phosphate; Application methods; Calcareous soils; Solid and liquid

http://dx.doi.org/10.19045/bspab.2018.700128