COMPARATIVE EFFECTIVENESS OF UREA N, POULTRY MANURE AND THEIR COMBINATION IN CHANGING SOIL PROPERTIES AND MAIZE PRODUCTIVITY UNDER RAINFED CONDITIONS IN NORTHEAST PAKISTAN

SUMMARY A field experiment was conducted to evaluate the comparative effectiveness of poultry manure, urea N and the integrated use of both in changing soil properties, nutrient uptake, yield and yield attributes of maize grown at Rawalakot, Azad Jammu and Kashmir, Pakistan. Treatments include control without any amendment (N 0 ); urea N (UN) = 120 kg N ha −1 (N 120U ); UN = 150 kg N ha −1 (N 150U ); poultry manure (PM) = 120 kg N ha −1 (N 120PM ); PM = 150 kg N ha −1 (N 150PM ); UN = 90 kg N ha −1 + PM = 30 kg N ha −1 (N 90U+30PM ); UN = 60 kg N ha −1 + PM = 60 kg N ha −1 (N 60U+60PM ); UN = 30 kg N ha −1 + PM = 90 kg N ha −1 (N 30U+90PM ). N fertilization from different sources and combinations increased dry matter yield from 5206 kg ha −1 in the control to 5605–5783 kg ha −1 and grain yield increased from 1911 kg ha −1 to 2065–3763 kg ha −1 . Application of the highest rate of urea N recorded the highest grain yields of 3763 kg ha −1 , double the control. The proportional increase for N 90U+30PM and N 60U+60PM was 85 and 83% while PM alone gave lower yields (41 and 44%) than the respective urea N treatments. Integrated use of urea + PM proved superior to other treatments in enhancing the uptake of N, P and K in plants. Averaged across two years, uptake of N, P and K in N 90U+30PM and N 60U+60PM was 88 and 85, 16.5 and 17.5, and 48.5 and 53.5 kg ha −1 , respectively compared to 52.5, 11.5 and 33.5 kg ha −1 in the control. Nitrogen use efficiency (NUE) varied from 29% in PM treatments to 30–39% in combined treatments while NUE of 40% was recorded for urea N treatments. Application of PM lowered soil bulk density from 1.19 t m −3 in the control to 1.10 and 1.05 t m −3 in N 120PM and N 150U , enhanced pH from 7.39 to 7.65 and 7.78 and increased soil organic matter (22 and 32%), total N (21 and 26%), available P (44 and 55%) and available K (10 and 15%) compared with the control. Economic analysis suggested the use of 50% recommended mineral N (60 kg N ha −1 ) with PM saves the mineral N fertilizer by almost 50% compared to a system with only mineral N application. In addition, increase in N efficiency, plant nutrition and soil fertility associated with combined treatment would help to minimize the use of high cost synthetic mineral fertilizers and represents an environmentally and agronomically sound management strategy.