Groundwater Depletion and Degradation in the North China Plain: Challenges and Mitigation Options

Groundwater is an important natural resource in the North China Plain (NCP) with high economic benefits and social significance. It fulfills 60% of drinking and 70% of irrigation water requirements. In this review, the information is retrieved from high-quality articles published in MEDLINE and other sources. We saw that groundwater is declining faster (>1 m yr(-1)) and polluting with NO3- (>30 mg L-1) due to excessive water pumping and application of a nitrogen (N) fertilizer, respectively. The water pumping (>600 mm ha(-1) yr(-1)) for agricultural purposes in the region is higher than the recharge amount (<200 mm yr(-1)). The low recharge is the result of low rainfall (<600 mm yr(-1)), and high evapotranspiration (>800 mm yr(-1)) under the impact of dominant vegetative characteristics of winter wheat-summer maize (W-W-S-M) rotations, covering >80% of the land. Furthermore, N application exceeds the crop assimilation capacity (>250 kg ha(-1) yr(-1)) and leach deep down (>50 kg ha(-1)) as well as loss in the atmosphere. Presently, Beijing, Tianjin, and Hebei are ecologically the most affected areas. We suggest that excessive water and N fertilizer use for intensive cropping systems should be controlled by paying high attention to groundwater-friendly farming practices. In addition, artificial groundwater recharge options and their safe utilization would be explored across the region to replenish aquifers. This literature review contributes valuable insights to the knowledge bank and offers a foundation for further research and policy development.