Soil carbon fractions as influenced by long-term integrated nutrient management under rice-wheat cropping system in calcareous soil of north Bihar

A 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 oxidisable carbon fractions of soil.