%0 Journal Article
%A Sahrawat, K L
%A Rahman, M H
%A Rao, J K
%D 1999
%F icrisat:1822
%I Kluwer
%J Nutrient Cycling in Agroecosystems
%N 1
%P 93-98
%T Leaf phosphorus and sorghum yield under rainfed cropping of a Vertisol
%U http://oar.icrisat.org/1822/
%V 54
%X A field experiment was conducted at Patancheru, Andhra Pradesh in 1987-89 to study the response of sorghum cv. CSH 6 to fertilizer P (0, 10, 20 and 40 kg/ha) on a Vertisol low in extractable P. One sorghum crop was grown each year during the rainy season (June to September). Tissue samples from the newest, fully-developed leaf were collected at 50% flowering stage to establish the relationship between leaf P concentration and grain yield. During the three years, sorghum grain yield and leaf P concentration increased in response to P application up to 40 kg/ha. Leaf P concentration was linearly related to grain yield (r² varied from 0.724 to 0.993). The critical leaf P concentration at 90% of the maximum grain yield was about 0.25% P. Phosphorus content in the grain was not significantly correlated to yield.