Effect of cropping systems and fertilizer levels on the nutrient uptake and yield by sorghum in rainfed vertisols

Field experiments conducted during the rainy seasons of 1994–95, 1995–96 and 1996–97 on rainfed vertisol showed that sole cropping of sorghum removed more of N and P₂O₅ than from sorghum + cowpea and sorghum + pearl millet system. The N uptake was higher in sole sorghum followed by sorghum + pearl millet system whereas,the P₂O₅ and K₂O uptake were higher in sole sorghum followed by sorghum + cowpea system. The uptake was linear with respect to applied fertilizers in all the cropping systems studied. The grain and straw yield of sorghum were higher when grown as sole crop. Application of fertilizers at N80: P40 and N60: P30 kg/ha significantly increased the grain yield.