Effects of the amounts of phosphate fertilizer, and of the proportions of water-soluble phosphate in the fertilizers tested on the phosphorus nutrition of sorghum

Abstract

SUMMARYA field experiment was made with sorghum hybrid CSH-1 during the rainy seasons of 1968 and 1969 on a sandy loam soil to study the influence of amounts and sources of phosphate fertilizer on phosphorus nutrition. Concentration of P in the crop and uptake increased with increasing amounts of phosphate and with increasing proportions of water-soluble P in triple superphosphate-dicalcium phosphate and triple superphosphate-rock phosphate mixtures. Relative effectiveness values were calculated from P uptake at harvest by a multiple regression method. For triple superphosphate, nitrophosphate (30% water soluble P), dicalcium phosphate and rock phosphate (from Jordan) the values were respectively, 100, 74, 61 and 22.