A greenhouse experiment was conducted to examine the relative suitability of solution P concentration and various measures of supply parameter as the P indices. Supply parameter valuesat agivenlevel of Paddition were calculatedon the basis of quantity-intensity relationships obtained prior to and after air-drying of soil following P addition. Labile P was a better measure of quantity factor for determining supply parameterthan the sum of added P plus native P when intensity measurement was taken after air drying of soil following P addition. The initially adjusted solution P concentration of 0.3 mg VI was required for optimum wheat yield in Inceptisol and Vertisol, whereas a level of 0.20 mg P V was sufficient in Alfisol. Solution P concentration was as good index of P fertilization as supply parameters whose value for optimum yield varied with soil type.
P fertilization indices, supply parameter, solution P concentration, resin exchangeable P, Inceptisol, Vertisol, Alfisol, wheat
