Comparison of satellite derived water and radiation use efficiency based wheat yield models over semi-arid regions.

摘要

Water use efficiency (WUE) and radiation use efficiency (RUE) based approaches were attempted to predict wheat yield of major wheat growing districts over semi-arid agro ecosystem of Qujarat. RUE approach through CASA (Carnegie-Ames-Stanford) model was found to produce better yield prediction accuracy (RMSE 17.7% of reported mean) as compared to the RMSE (18% of reported mean) from WUE approach. Moreover, the correlation coefficient between predicted and reported district yield was also found to be higher (r=0.90) in RUE based approach than the other one (r=0.80). District mean WUE were computed for three growth stages viz. vegetative, flowering and grain filling of wheat using MODIS AQUA derived evapotranspiration (ET) values. It was found that the WUE were generally higher in vegetative and flowering stages as compared to grain filling. The wheat yield prediction from water use and stage specific WUE were carried out for same seasons. The better correlation found from 0.57 to 0.77 at flowering stage.