Validation of Soil Test Based Fertilizer Prescription Equations under Integrated Plant Nutrition System for Desired Yield Target of Wheat

Soil test based fertilizer prescriptions for desired yield target of wheat were developed under Integrated Plant Nutrition System (IPNS) for Ooty soil series (Typic Haplohumult) of Tamil Nadu. To validate the equations, experiments were conducted in Salem and Namakkal districts at farmers holding on similar soil series. The results revealed that the per cent achievement of the aimed yield target was within + 10 per cent variation confirming the validity of the equations. STCR treatments recorded significantly higher yield, Response Ratio (RR) and BCR over blanket while STCR - IPNS treatments recorded relatively higher yield, RR and BCR over STCR-NPK alone treatments. The highest mean yield of 41.63 q ha-1 was recorded with STCR-IPNS 40 q ha-1 with an increase of 55.8 per cent over blanket. Post - harvest soil fertility with respect to available N, P and K revealed that there was sustainability of soil fertility in STCR treatments. Therefore soil test based fertilizer prescription can be recommended to hilly and foothill areas of Tamil Nadu for achieving 40 q ha-1 of wheat.