Fertilizer recommendation based on soil test crop response for high targeted yield

Soil test crop responses (STCR) studies were conducted with rice cv. ADT 43 at the Experimental Farm, Annamalai University, Annamalainagar. The field consisted of four strips(I, II, III, IV) and received N0P0K0,N1/2,P1/2,K1/2, N1P1K1,N2,P2K2 fertilizers, respectively. The results indicated that the grain yield in strip I (2.36 t ha-1) increased to strip IV (5.69 t ha-1) with graded levels of NPK fertilizers due to better nutrient uptake. Followed by test crop (STCR) experiment was carried out with rice cv. ADT 36 in the same field during wet season. By using grain yield, initial soil test values, uptake of nutrients and fertilizer doses applied, the three basic parameters viz., NR,CS,CF were worked out, Fertilizer adjustment equations (FAEs) were formulated. Finally the fertilizer recommendations were worked. The results of this STCR experiment revealed that when the initial soil available NPK status were 200, 10, 250 kg ha-1, the FN, FP2O5, FK2O recommendations to get 60 t ha-1 were 233:100:107 kg ha-1 for fertilizers alone application. The fertilizer recommendations for the application of fertilizers + FYM + Azospirillum, for the same yield target were 185:86:82 kg ha-1 due to balanced fertilization.