Water and nutrient use efficiencies in wheat under different fertiliser gradients

The field experiment was conducted on wheat at the Central Research Farm (CRF), Gayeshpur encompassing the new alluvial zone of West Bengal, to evaluate the interactions and use efficiency of water and nutrient under different fertiliser gradients. The experiment was laid out in factorial RBD with three treatments [T₁: 100:50:50:: N:P:K kg ha⁻¹, T₂: 120:60:60:: N:P:K kg ha⁻¹, T₃: 150:75:75:: N:P:K kg ha⁻¹], eight sampling dates and three depth of sampling with three replications. Pearson's correlation between available N,P,K and soil moisture @ 15 cm depth is positively correlated, significant at 0.01 level (2-tailed), negatively correlated @ beyond 15 cm depth. The nutrient-use-efficiency were computed in terms of Recovery Efficiency [RE= kg nutrient taken up per kg nutrient applied] which shows that higher levels of fertilizer administration did not always turn up with best nutrient efficiency of standing crop. Recovery Efficiency of Nitrogen is high in T₂ and T₃ (0.58). R.E of phosphorus and potassium are high in T₂ (P-0.21, K-1.22). The contribution of irrigation in water balance equation was 173.53 mm; while it was 99.0 mm for rainfall and the seasonal evapotranspiration of wheat, regardless of different NPK fertilizers levels, was 192.76 mm. Fertilizer nutrient management was found to influence the water use efficiency of wheat. Application of incremental doses of nutrients increased the water use efficiency of crop concomitantly. Water use efficiency (kg/ha-mm) is highest in T₃ (7.16). The conspicuous difference was mainly due to the improvement in the grain yield of wheat.