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
G. Kiran Reddy *
Department of Soil Science and Agricultural Chemistry, PJTSAU, Hyderbad, India.
S. H. K. Sharma
Department of Soil Science and Agricultural Chemistry, PJTSAU, Hyderbad, India.
K. Chandra Shaker
Department of Soil Science and Agricultural Chemistry, PJTSAU, Hyderbad, India.
P. Ravi
Department of Soil Science and Agricultural Chemistry, PJTSAU, Hyderbad, India.
Muneshwar Singh
AICRP on Long Term Fertilizer Experiments, Indian Institute of Soil Science, Bhopal, India.
W. Ravi
AICRP on Long Term Fertilizer Experiments, Indian Institute of Soil Science, Bhopal, India.
*Author to whom correspondence should be addressed.
Abstract
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.
Keywords: Long term fertilizer experiment, rice, sustainability yield index, integrated treatment, yield trends, time series analysis.