Effect of source and level of phosphorus on the yield of sorghum (Sorghum bicolor) under dryland conditions

A field experiment was conducted during 1993-94 to 1995-96 on Vertisol to assess the effects of 2 sources and levels of phosphorus on the yield of winter (rabi) sorghum [Sorghum bicolor (L.) Moench] under dryland conditions. The grain yield of rabi sorghum was not influenced by different sources of phosphorus and recorded 21.94 q/ha and 20.75 q/ha grain yield under single superphosphate and diammonium phosphate respectively. The effect of various levels of phosphorus was significant and the magnitude being 18.93, 21.29, 21.63 and 22.53 q/ha respectively at 15, 30 45 and 60 kg P2O5/ha respectively. Similarly, grain and straw yields increased significantly up to 60 kg P2O5/ha. As per the equations, the optimum dose of phosphorus for rabi sorghum was worked out to be 50.6 kg P2O5/ha.