Estimation of groundwater use by crop production simulated by DSSAT-wheat and DSSAT-maize models in the piedmont region of the North China Plain

摘要

Sustainable water use is in serious crisis in the piedmont region of the Taihang Mountains in the North China Plain, owing to rapid groundwater drawdown. Estimating the water requirement for agriculture, the biggest user of groundwater, will be helpful in understanding groundwater decline. Through the use of DSSAT-3.5 wheat and maize models, we assessed water use in winter wheat and maize, two staple crops in the region, in 1987-2001. Trends between groundwater change and simulated agricultural water use were compared. The results showed that groundwater decline was sensitive to simulated crop water requirement and irrigation requirement. According to regression analysis, 100 mm of water requirement by cultivated land (mainly wheat and maize) resulted in about 0.64 m of groundwater decline. This relationship might be useful in understanding the regional water balance and to help decision-makers control groundwater decline through controlling crop water use or through long-distance water transfer. The study demonstrated the usefulness of using the DSSAT model for estimating crop water use and the effectiveness of clarifying the reason for groundwater decline using the simulation results of water use.