Sustaining Productivity of Wheat-Soybean Cropping System through Integrated Nutrient Management Practices in the Vertisols of Central India.
Uma Kant Behera, Indian Agricultural Research Institute, Pusa Campus, New Delhi 110012, India and Hira Nand Pandey, IARI, Regional Station, Indore (Madhya pradesh), India.
Wheat-soybean is one of the most dominant cropping systems in the Vertisols of central India. Cultivation of durum wheat in winter season (November to April) has an enormous potential due to congenial climate and increasing global demand, scope for value addition, while soybean in rainy season (June to October) has witnessed a phenomenal growth in the last 2 decades in the region. Beside including a legume (soybean) in sequence with a cereal crop (wheat), combined use of available organic sources along with chemical fertilizers may prove beneficial for long-term productivity and sustainability of the system. It may also help in improving the quality of durum wheat, which is important from export point of view. A long-term experiment was conducted during 1995-2002 under the fine-textured Vertisols at Indore, India to study the effect of combined use of Farm Yard Manure (FYM), poultry manure, vermicompost and biofertilizers (Azotobacter + phosphate solubilizing bacteria) with 50 and 100% NPK on wheat, and residual effect on following soybean. Grain yield of aestivum wheat in the initial 2 years and durum wheat in the later 3 years was significantly increased with 50% NPK + poultry manure @ 2.5 t/ha or FYM @ 10 t/ha compared with 50 or 100% NPK alone. However, the highest productivity was obtained when these organic sources were applied along with 100% NPK, indicating that NPK fertilizers alone did not provide adequate and balanced nutrition for potential yield of the crop. Quality parameters of durum wheat viz. protein content, hectoliter weight and sedimentation value showed improvement, and yellow berry content was also significantly lower with combined use of organic and inorganic fertilizers compared with NPK alone and control. Soybean did not show much response to residual effect of treatments in most years, although the yields were comparatively better under the combined use of 100% NPK + FYM or poultry manure given to wheat. Wheat gave higher profit than soybean, particularly in the later years due to lower yields and market price of soybean. However, the superiority of FYM as well as poultry manure along with NPK was evident on the profitability of the system. Various soil fertility parameters showed conspicuous improvement over the initial status under the treatments of FYM and poultry manure. Sustainability yield index was significantly greater under 100% NPK + FYM or poultry manure than other treatments. It was concluded that application of available organic sources, particularly FYM and poultry manure, along with full recommended dose of NPK to wheat was essential for improving productivity, grain health, profitability, soil fertility and sustainability of wheat-soybean system.