Variation of relative evapotranspiration with available soil moisture conditions in wheat

Field experiment was conducted on wheat variety WH-147 with five dates of sowing and three irrigation levels on the sandy loam soil of Haryana to study the behaviour of relative evapotranspiration (RET) with available soil moisture. In I₀ treatments during early and late sown conditions the decrease in RET with decreasing soil moisture behaves in a complex functions. RET decreased slowly in early as well as in late sown conditions but, in normal sown conditions the decrease in RET was faster. The decreasing trend of RET with the decreasing soil moisture is quite complex as the soil moisture in the profile is-controlled by the atmospheric demand for evapotranspirational rate due to external environmental conditions.