Long Term Effect (17 Years) of Different Nutrient Management Practices on Crop Yield Trends, Soil Productivity and Sustainability in Rice-rice Cropping System under Semi Arid Tropical Climatic Condition in an Inceptisol of India

A long term fertilizer experiment was initiated at PJTSAU sub campus, Jagtial, Telangana state, during rainy season of the year 2000-01 in rice-rice continuous cropping system. The experiment was conducted in a fixed plan layout with 11 treatments (and 1 fallow) which included various combinations of inorganic and organic fertilizers and was replicated 4 times under randomized block design. At the initiation of Experiment the soil properties were clay texture with pH 8.22, organic carbon 7.9 g/kg, Available Nitrogen (N) 107.6 kg/ha, Available Phosphorus (P) 19.6 kg/ha and Available Potassium (K) 364 kg/ha. The study was conducted over a period of 17 years comprising of 34 cropping cycles, in rainy season where all treatments received optimum dose (100% NPK), super optimum dose (150% NPK) and integrated treatments (100% NPK + FYM 5 t/ha) (FYM – farm yard manure) gave onpar yields. However in the post rainy season, 150% NPK treatment gave superior yield compared to all treatments except NPK+ FYM 5 t/ha. NPK + FYM 5 t/ha and 150% NPK treatments recorded the most sustainable yield index (SYI) of 0.65 in rainy and post rainy season respectively. Over all mean SYI, was highest for NPK + FYM 5 t/ha and 150% NPK i.e., 0.63 and the least was observed in 100% N alone 0.50. There was an increase in organic carbon, Available N, Available P and Available K in NPK + FYM 5 t/ha and 150% NPK treatments compared with other treatments. Treatment receiving N alone i.e. imbalance nutrient supply retrogress the crop yields and soil productivity in long run.