Site specific NPK recommendation in wheat (Triticum aestivum) for sustained crop and soil productivity in mollisols of Tarai region

Field experiment was conducted in three consecutive rabi seasons of 2006–07 to 2008–09 at the Crop Research Centre of G.B. Pant University of Agriculture and Technology, Pantnagar, Uttarakhand, India to study the effect of ‘site specific NPK recommendation’ in wheat {Triticum aestivum (L.) emend. Fiori & Paol} for sustained crop and soil productivity in mollisols of Tarai region. The experiment consisted of eight fertilizer combinations comprising of N, P₂O₅, and K₂O. Treatments were T₁- 170: 60: 120, T₂- 170: 30: 120, T₃- 170: 0: 120, T₄- 170: 30: 80, T₅- 170: 30: 40, T₆- 170: 30: 0, T₇- 150: 60: 40 and T₈- 120: 40: 0, which were laid out in RBD with four replications. Experimental findings revealed that application of N, P₂O₅ and K₂O @ 170: 60: 120 kg/ha produced maximum grain yield, which increased by 7.1% and 16.5% over recommended NPK (150N: 60 P₂O₅: 40 K₂O kg/ha) and farmer practice (120 N: 40 P₂O₅: 0 K₂O kg/ha), respectively. Application of nitrogen @ 120 kg N/ha and phosphorus @ 40 kg P₂O₅/ha as farmer fertilizer practice produced lowest grain yield. Increasing fertilizer nitrogen up to 170 kg N along with 30 kg P₂O₅ and 80 kg K₂O increased the crop growth, yield contributing characters and yield of wheat significantly. Significant response of P was observed up to 30 kg P₂O₅/ha and in case of K up to 80 kg K₂O/ha over no application, whereas further increase in P and K doses had non–significant response. However, fertility status of soil after harvest of three cycles of crop increased with increased application of N, P and K upto 170 kg N, 60 kg P₂O₅ and 120 kg K₂O/ha. Thus, the results suggests that application of N, P₂O₅ and K₂O @ 170, 30 and 80 kg/ha to wheat crop is required for achieving higher productivity on sustainable basis besides maintenance of soil fertility in Tarai region of north India.