Soil test crop response calibration studies on rainfed castor (Ricinus communis) in Alfisols.

摘要

Soil test crop response calibration studies were conducted with castor bean cv. Jyothi as a test crop in Alfisol in Andhra Pradesh, India, during the rainy (kharif) season of 2006. In the targeted yield approach for calibrating and formulating fertilizer recommendations, the basic data computed were: (i) nutrient requirement in kg/100 kg of economic produce, (ii) percent contribution from soil available nutrients (% CS), and (iii) percent contribution from applied fertilizers (% CF). The N, S and Zn requirements (kg/100 kg) to obtain a seed yield of 100 kg in Alfisol under rainfed conditions were 4.68, 1.60 and 0.01, respectively. Percent contribution from soil and fertilizers in Alfisol were found to be 17.33 and 12.75 for N, 67.27 and 63.26 for S, and 5.19 and 0.34 for Zn. Fertilizer adjustment equations and Ready Reckoner for interpolating optimum fertilizer rates at varying soil test values for attaining yield targets of 800-1100 kg/ha were developed.