Validation of quefts model for site specific nutrient management in white YAM (Dioscorea rotundata POIR.)

Yam (Dioscorea spp.) is an important tropical tuber crop contributing to food and nutritional security of economically backward and ethnic people of many countries in Africa, South America and Asia. Yam yield in the major growing environments of India has been stagnating despite the development of high yielding varieties and increasing use of chemical fertilizers. On-station experiments were conducted to evaluate the performance of site-specific nutrient management (SSNM). Field and crop specific NPK rates were calculated using quantitative evaluation of fertility of tropical soils (QUEFTS) model. The yield advantage of SSNM over current recommendation was 8.16 t ha⁻¹ (mean of 3 yrs). The increase in agronomic efficiency and recovery efficiency of N in SSNM over current recommendation was 24.1 kg kg⁻¹ and 0.09 kg kg⁻¹, respectively. Similar increases were observed for P and K. The results showed the potential of SSNM in increasing yield and nutrient use efficiency of white yam.