Estimate of the crop coefficient for Eucalyptus cultivated under irrigation during initial growth

Abstract

The expansion in areas planted with eucalyptus crops has raised concern about the effects these may have on water resources and existing correlations between water use and crop productivity, which calls for better understanding of water requirements by plant species. The objective of this study was to determine the water requirements of an irrigated eucalyptus crop, having the estimated dual crop coefficient (dual Kc) as a reference. Mean values found for estimated crop coefficients were 0.57, 0.13 and 0.70 for Ke, Kcb and Kc respectively during initial growth stage, and 0.01, 0.81 and 0.82 for Ke, Kcb and Kc respectively during the mid-season stage. The methodology used in this study is not intended to replace field measurements for development of Kc curves. However, it provides a consistent method to evaluate values measured while providing means for estimating variations in values of Kc according to change in the soil fraction covered by vegetation.