Nutrient Use Efficiency of Groundnut as Influenced by Nitrogen and Phosphorus Levels in Northern Transition Zone of Karnataka

The highest nutrient use efficiency always occurs at the lower parts of the yield response curve, where fertilizer inputs are lowest, but effectiveness of fertilizers in increasing crop yields and optimizing farmer profitability should not be sacrificed for the sake of efficiency alone. The groundnut cultivar JL 24 was tried during 2012 with eleven ratios of nitrogen (N) and phosphorus (P₂O₅) fertilizers with potassium level as constant (25 kg K₂O ha⁻¹). The nutrient use efficiency like nitrogen and phosphorus efficiency and physiological efficiency of nitrogen and phosphorus levels were taken during initial and harvesting stages of fertilizer and unfertilized treatments. These are increased due to increasing N/P fertilizer ratios from 0.00 to 1.00. N use efficiency varied from 1.27 (1.00) to 2.20 Kg N/kg (0.33 and 0.50) and P use efficiency ranged from 0.09 (0.40) to 0.21 Kg P₂O₅/kg (0.83) in different treatments and physiological efficiency of N varied from 9.67 (0.56) to 12.32 kg grain/kg N uptake (0.83) and physiological efficiency of P ranged from 63.15 (1.00) to 94.47 kg grain/kg P₂O₅ uptake (0.83) in different treatments was observed as compared to all other N/P fertilizer ratios.