Phosphorus Response Effects on Macro-and Micronutrient Removal by Sorghum under Rainfed Cropping on a Vertisol

Amounts of N, P, K, Ca, Mg, Na, Fe, Zn, Mn and Cu absorbed by sorghum (cv CSH 6) grown with four P levels (0, 10, 20 and 40 kg P ha⁻¹) were determined in a field experiment at the ICRISAT Centre, Patancheru (Andhra Pradesh) under rainfed conditions for three consecutive years (1987–89). The soil was a calcareous Vertisol, very low in available P. Fertilizer P increased grain and stalk yields in all the three years. The uptake of macro-and micronutrient elements accordingly increased with the increase in yield. Phosphorus application also increased the nutrient harvest index for macro- and micronutrient elements. Ratio of nutrient concentrations in the grain relative to stalk was widest for P (5: 1) and narrowest for Ca (0.03:1).