Response of sunflower (Helianthus annuus L) to phosphorus application in vertisols

Abstract

Field experiments in vertisols of low, medium and high available soil phosphorus status were conducted to study the response of graded levels of P application to sunflower hybrid (KBSH-1). Effect of P to sunflower in increasing yield and yield attributes was more pronounced in low P status soil. Response equations for seed yield of sunflower at an applied P level have been worked out. Nutrient use efficiency and productive efficiency were also computed. Soil available P status was found to vary significantly only in low P status. Critical P level in soil was found to be 20 kg P ha-1, below which sunflower may respond to phosphorus application.