Quantification of wheat crop evapotranspiration and mapping: A case study from Bhiwani District of Haryana, India

In this study an attempt has been made to estimate the actual wheat crop evapotranspiration (ETc) by Surface Energy Balance Algorithm (SEBAL) and standardized FAO-Penman-Monteith (FAO-PM) method. Improved knowledge of evapotranspiration (ET) helps in understanding the water balance of any region. The results obtained through measured lysimeter, SEBAL and PM method were evaluated through statistical performance measure tests. ETc estimated from SEBAL was found to correlate significantly as R2 (0.91) with the measured ETc of lysimeter. ETc estimated by SEBAL was also compared with PM ETc with the help of crop coefficient and was found to correlate significantly as R2 (0.85). The other statistical parameters (RMSE = 0.56, nRMSE = 0.09, MAE = 0.26, NRMSE = 0.20, R-RMSE = 0.27, NSE = 1, d = 0.87 (≈1)) were also showing a good agreement between SEBAL ETc and PM ETc. The findings of work have suggested that SEBAL model shows a good potential to estimate spatial ETc for the region. Additionally the validation of models results were performed with the analysis of correlation between models ETc and district level wheat production and area under crop of five years. The results of this analysis outline that water availability and good amount of rainfall gives higher wheat yield and resulted into more ETc.