An experiment was conducted in screenhouse on fourteen representative soils of Haryana to assess the suitability of some soil test methods of available P and different P fractions to predict the response of applied P and establish the critical limit of available P for sunflower (cv. Sungene 85). Multiple regression analysis showed that the variations in Olsen, Soltanpour and Schwab, AB-EDTA and Mehlich II P were accounted for by Al-P alone to the extent of 63.3, 67.9, 62.1 and 66.6 per cent, respectively. The critical limits of available P for sunflower were established as 18.2, 14.7, 20.1 and 16.2 kg ha−1 for Soltanpour and Schwab, Olsen, AB-EDTA and modified Olsen soil tests, respectively.
Soil test P, P fractions, critical limit, sunflower
