Modelling the Grain Yield of Wheat in Irrigated Saline Environment with Foliar Potassium Fertilization

Abstract

In the present study, an effort was made to calibrate and validate a crop model using the experiment generated data pertaining to growth and yield of wheat cultivars under irrigated saline environment using foliar potassium application. A field experiment was conducted at Water Technology Centre research farm, Indian Agricultural Research Institute, New Delhi, in split–split plot design during rabi 2011–2012 and 2012–2013 to generate data for simulation of FAO AquaCrop model. Two wheat cultivars (i.e. one salt tolerant KRL-1-4 and other salt susceptible HD 2894) under four salinity levels, viz, GW (1.7 dS m⁻¹), 4, 8 and 12 dS m⁻¹ were experimented under foliar and non-foliar treatments. AquaCrop model was calibrated using experiment data of rabi 2011–2012 and validated with data of rabi 2012–2013. The model evaluation parameters, viz, model efficiency (ME), index of agreement (d) and R² pertaining to grain yield of both wheat cultivars predicted by validated model were averaged to be 0.86, 0.95 and 0.96, respectively, under all treatment levels. Moreover, the simulated biomass yield of both the cultivars was with average values of ME, d and R² as 0.91, 0.97, and 0.93, respectively. However, model validation results for water productivity were 0.60, 0.82 and 0.93 for ME, d and R², respectively. It was observed that the AquaCrop model simulation for grain yield was better as compared to biomass and water productivity for all treatment levels. Validated model resulted in predicted grain yield of both wheat cultivars with low prediction error (i.e. 1.77–6.52%) up to 8 dS m⁻¹, whereas at 12 dS m⁻¹ salinity level, the prediction error increased and varied from 21.7 to 37.5%. Nonetheless, the FAO AquaCrop model can be used with acceptable accuracy for simulation of grain yield of wheat cultivars using saline irrigation up to 8 dS m⁻¹ with foliar potassium fertilization.