A Sensitivity Analysis of Parameters Influencing Crop Water Requirements

Abstract

The modified version of Penman 's formula (Doorebbos and Pruitt 1977) was used to assess the relative significance of the contribution by each of five parameters towards the magnitude of maximum evapotranspiration, ETm, in maize. The parameters tested were leaf area index, net radiation, mean air temperature, wind run, and vapor pressure deficit. Maximum evapotranspiration was found to be most sensitive to changes in leaf area index. Among the climatic parameters tested, net radiation played the most significant role in determining the magnitude of ETm, whereas the contribution from temperature was the least significant. The physical significance of the results is compounded by non-linear changes in the independent variables corresponding to increases in the dependent variables.