Response of fed dung composted with rock phosphate on yield and phosphorus and nitrogen uptake of maize crop

Two experiments were conducted to determine the extent of phosphate (P) solubility from rock phosphate (RP) fed dung through composting with RP and to determine its effects on yield and P uptake of maize crop. Different composts of RP fed dung and simple dung were prepared with and without RP. Field experiment was conducted on silty clay loam soil at the research farm of Khyber Pakhtunkhwa Agricultural University, Peshawar to study the effect of RP fed dung composted with RP on the yield, yield components and P uptake of maize (Zea mays. L. Azam).The fertilizers, N, P and K, were applied at the rate of 120- 90- 60 kg ha-1, respectively in a randomized complete block design (RCBD) with three replications. Compost and urea were used as a fertilizer source for N, compost and single super phosphate (SSP) as a fertilizer source for P and sulphate of Potash (SOP) was used as a fertilizer source for K. Application of the compost prepared from RP fed dung with RP, improved the yield and yield components of maize crop. The maximum and significantly (P ≤ 0.05) increased grain yield of 3264 kg ha-1, total dry matter yield of 9634 kg ha-1, stover yield of 7293 kg ha-1, and thousand grain weight (231 g) of maize crops were recorded in the treatment where full dose of the prepared compost was applied with half dose of SSP, followed by the treatment of full recommended SSP. The data of soil analysis showed increase in soil organic matter content and a decreasing trend in soil pH values. Application of compost with SSP significantly (P ≤ 0.05) increased soil N and P concentration and their uptake by the maize plants. Maximum net return of Rs. 24060 ha-1 with a value cost ratio (VCR) of 3.0:1 was obtained by the application of full dose of compost with half SSP, followed by the treatment of full dose of compost applied alone with a net return of Rs. 14555 ha-1 and VCR of 2.8 : 1. Results suggest that application of the compost prepared from RP fed dung with RP is economical, environment friendly and has the potential to improve maize yield, plants N and P uptake.   Key words: Maize, dung, rock phosphate, composts, yield, plants P uptake.