Nutrient Recycling and Its Relationship with Biofertility Indicators of Soil Health and Nutrient Uptake in a Rice (Oryza sativaL.)-Wheat (Triticum aestivumL. emend. Fiori & Paol) Cropping Sequence

The effect of nutrients recycled through the incorporation of farmyard manure, crop residue, and green manure was studied in the Indo-Gangetic plain of India during 2006 to 2009. The biofertility indicators such as soil health, uptake of nutrients by the crops, yield, and yield attributes were studied in the cropping sequence of rice (Oryza Sativa L.)-wheat (Triticum aestivum L. emend. Fiori & Paol). The recycling of organic residues is evident from the results as the values of soil microbial biomass carbon (364.0 μg/g soil) and carbon dioxide evolution (1.75 μg/g soil/h) were recorded. The results show that dehydrogenase and phosphatase enzymes activities have increased significantly after 3 years as a result of the incorporation of residue plus green manure. The mean yield data of rice and wheat crops revealed that incorporation or burning of residue in the field resulted in a slightly higher yield over residue removal. Further, higher grain yield (rice = 7.54 t/ha, wheat = 5.84 t/ha) was recorded in residue plus green manuring treatment. Total uptake of the nutrients by rice–wheat crops in sequence was highest (N 203.70, P 37.20, K 203.60 kg/ha) in case of crop residue plus green manuring treatment.