Effect of organic v/s chemical nutrient packages on productivity, economics and physical status of soil in rice (Oryza sativa) – potato (Solanum tuberosum) cropping system in Chhattisgarh

Field experiments were conducted at Raipur in Inceptisols between 2003–04 and 2007–08 to compare organic, integrated and chemical fertilizer nutrient inputs pakages in scented rice (Oryza sativa L.) – potato (Solanum tuberosum L.) a high value cropping system. Seven different nutrient treatments, 5 of them having use of organic inputs and 1 each having integrated (50% through fertilizers and 50% through organic nutrients) and 100% through fertilizers were studied in RBD with 3 replications. Organic transition effect in which decline in yield from 1 to 3 years and again increase in yield was noticeable in rice under organic nutrient inputs packages. These treatments followed a steady increase and registered 20 to 50% more yield at the end of study compared to first year yield i.e. 2003–04. However, effect of different organic inputs packages on potato tuber yield was not stable over the years. Total productivity in terms of rice equivalent yield of the system (13.36 tonne/ha) and total net return (Rs 92,634/kg) was highest with chemical fertilizer treatment closely followed by integrated inputs use. 100% N (1/3 each from cowdung manure, neem cake and composed crop residue) appreciably increased the organic carbon (6.3 g/kg) over initial value (5.8 g/kg). However, availability of P and K did not show any perceptible change after completion of five cropping cycles under organic as well as integrated nutrient approaches.