Crop production is typically influenced by stochastic factors such as soil variability and residual nutrient availability and residual nutrients in the soil. For optimal dose of fertilizer recommendations the prediction of carry-over on residual nutrients in the soil matters much. In the present study Soil Test and Crop Response Correlation Scheme (STCR) trial data were used to estimate the carry-over of N, P and K in irrigated groundnut production at Vridhachalam, Regional Research Station, Tamil Nadu. The results indicated that 124 kg of N, 43 kg of P and 114 kg K ha−1 were available as residue in the soil. The sustainability requirements of fertilizers were also worked out to preserve the present status of soil health. The cost incurred to sustain the present soil status would be Rs. 1918 ha−1 and to meet the recommended dosage the farmer has to spend Rs. 1344 ha−1. If the available residue is exploited fully then there is no need to apply N, P and K to the succeeding crop. The mathematical model used to estimate carry-over of fertilizer was sensitized through reliability index which revealed that the estimation was correct with narrow deviation.
Ferlilizer nutrients, carry-over impacts, groundnut
