Field demonstrations were carried out in Inceptisol, Alfisol and Vertisol soils of Tamil Nadu, India in the farmer's field to find out the efficient method of phosphorus in a balanced fertilization programme on groundnut, cowpea and black gram crops. There is a concern over the farmers of this tract were applying inadequate, imbalanced, non-integrated fertilizers. The N : P use ratio of this tract was 2.6:1.0 during 1999-2000 has been increased to 3.0-1.0 during 2002-2003 indicated the imbalanced P fertilization there by 20-40% yield reduction in groundnut, cowpea and black gram crops. The soils were fine loamy calcareous to coarse loamy non-calcareous with low and medium available P status. The treatment for groundnut crop ( VRI-5 ) were farmers method ( NPK 17:17:17 kg ha-1 complex) , No phosphorus (NK 17:54 kgha-1 ), blanket (NK 17:54 kgha-1+ P as single super phosphate(SSP) 34 kgha-1 ) and Integrated Plant Nutrient Supply System – IPNS (NK 30:120 kgha-1 + P 60 kgha-1 as SSP + Phosphobacteria 2 kgha-1). The treatment for cowpea ( CO 2 ) and black gram ( TMV-1 ) were farmers method (25 kgha-1 N alone), blanket (25 kgha-1 N + 50 kgha-1P as SSP and IMPHOS Method (25 kgha-1 N + P 62.5 kgha-1 as SSP). The highest pod yield of 1900 kgha-1 was recorded for IPNS method over farmers method. The pod yield increase was 45% with a net profit of 16500 INR to the farmer. The highest pod yield of cowpea 1450 kgha-1 and 1320 kgha-1 pod yield of black gram with a net profit of 16100 INR and 12400 INR respectively for the application of 62.5 kgha-1 P as SSP. The IPNS method in groundnut was significantly profitable to the farmers. The IMPHOS method in cowpea and black gram increasing the net profit to farmers.