干旱区生态环境知识资源中心

Groundwater provides an important source of water for maize cultivation where the water table is shallow in the semi-arid Hailiutu River catchment of the Maowusu Desert on the Erdos Plateau in Northwest China. A HYDRUS-1D model of the unsaturated flow beneath a maize (Zea mays L.) field was calibrated and validated with measured soil water contents at various depths during the maize growing period from 30 April to 1 October 2011, and from 23 May to 27 September 2012, respectively. The model computed the actual maize evapotranspiration (ETa) as 580mm during the whole growing period from 30 April to 1 October 2011. The groundwater contribution to ETa was calculated to be 220mm, accounting for 38% of maize water use during the growing season in 2011. When the groundwater level drops below a depth of 157cm, maize can no longer use groundwater for transpiration. The irrigation water requirement increases with the increase of groundwater table depth. These results are very important for managing crop irrigation in the area.