Soil Fertility and Crop Productivity Changes due to Cotton-based Cropping Systems under Rainfed Conditions

A field experiment was conducted for three years on a Vertisol (Typic Ustochrept) under rainfed conditions to evaluate the effect of crop rotations, viz. cotton-jowar-arhar and their intercrops with soybean, viz. cotton+soybean, jowar+soybean and arhar+soybean, alongwith monocropped cotton and soybean at two levels of fertility and crop yields. The performance of the component crops (except jowar) was better in 1993–1994 than the previous two years owing to a more favourable rainfall distribution. The econontic yields, gross returns and LER were higher under intercropping system than their respective sole crops. Arhar+soybean was the most profitable system with highest LER during the years 1991–92 and 1992–93 and cotton+soybean was the most profitable in the year 1993–1994. Application of FYM improved the yields of jowar, cotton and arhar by 33.8, 20.4 and 16.6 per cent over NPK alone. FYM application for three years increased the soil available N to 239 kg ha⁻¹ from 229 kg ha⁻¹ and available P to 13.6 kg ha⁻¹ from 8.7 kg ha⁻¹.