Effect of long-term integrated nutrient management on soil pH and carbon mineralization in calcareous soil of North Bihar

Abstract

A laboratory study was conducted in an ongoing field experiment started during Rabi 1988-89 in calcareous soil at Research Farm of Dr. Rajendra Prasad Central Agricultural University, Pusa, Bihar. The experimental design was split-plot with four fertilizer levels (0, 50, 100 & 150% NPK) in main plots and four levels of manures (no manures, compost @ 10 t ha-1, crop residues and compost @10 t ha-1 plus crop residues) in sub-plots. The present investigation was undertaken with objectives to investigate the effect of combined use of NPK and different organics (compost and crop residues) on Soil pH and Carbon Mineralization under rice–wheat-cropping system. Continuous application of compost @ 10 t ha-1 plus crop residues, reduces the pH of soil by 3.66% than no manure application. Cumulative carbon mineralization significantly increased in treatments having both organic and inorganic fertilizers than of treatments having only inorganic fertilizers. Rate of mineralization increased in initial days of incubation after that it decreases.