Comparison of crop water requirements computed by single crop coefficient approach and dual crop coefficient approach

This study is to evaluate the water requirement of crop(ET) using single coefficient approach and dual crop coefficient approach under the condition of Shannxi Province and to compare ET estimation with observation data measured by lysimeter.The differences are analyzed.The result shows that dual crop coefficient approach is better than single crop coefficient approach in case the field is partly covered.However,the difference is insignificant if the field is fully covered.