Main Participants: CHEN Minjian, ZHAO Yong, YAN Long, ZHANG Sheng, LI Tongsheng, DONG Kebao, WANG Yong, ZHOU Fei, DENG Wei, LIU Yanhong, JIN Xiaohui, MA Jing, LI Hongzhi, YANG Guiyu, HU Yajie

This project aims to carry out theoretical and applied basic research on the major water resources and ecological problems caused by the development of water and land resources in the agro-pastoral ecotone of semi-arid regions. Under the condition of large-scale agriculture irrigation and groundwater extraction, grassland ecological space continues to shrink and groundwater level continues to decline in semi-grid regions, which poses a major threat to the survival and development of agricultural and pastoral areas. 

In response to the above series of problems, with the support of the nonprofit research projects of the Ministry of Water Resources, this project has carried out a long-term rolling tracking study on semi-arid regions with annual rainfall of 200-400mm, water surface evaporation greater than 1,000mm and drought index between 3 and 7. It is a forward-looking and basic theoretical technology of hydrology, water resources and ecological security specifically targeted at semi-arid regions with remarkable creativeness.

·   Having discovered the influence mechanism of irrigation on groundwater formation in semi-arid regions, quantitatively revealed the disappearance of irrigation return flow and the change process of precipitation recharging groundwater caused by micro-drip irrigation, analyzed the influence of the combination of these two approaches for water table balanced groundwater exploitation and replenishment, and studied the impacts of micro-drip irrigation on the vertical hydrological cycle in semi-arid regions.

·   Having formed an evaluation and analysis method for ecological pattern of agro-pastoral ecotone in semi-arid regions based on grassland natural attributes, established an evaluation method for regional ecological structure of agro-pastoral ecotone, and proposed the reasonable proportion of ecological landscape structure of grassland agro-pastoral ecotone in semi-arid region.

·   Having put forward the differentiated management of groundwater control levels in the agro-pastoral ecotone in semi-arid region, proposed the so called “red line” based on  the comprehensive study on the threshold groundwater table (including the threshold groundwater table of precipitation recharging groundwater and groundwater supplying vegetation) with physical mechanism and experimental evidence in semi-arid regions; established the model of groundwater dynamics and developed the principle and control criteria of groundwater well layout.

·   Having proposed the development pattern of circular economy in semi-arid regions based on ecological security, created the ecological security analysis tool for the industrial chain of circular economy in the economic and social development parttern of semi-arid regions and established an innovative technical method with fundamentality and practicability.

The research results have been applied and rolled out in Eastern Inner Mongolia in a timely manner bearing significant results, which have played a huge role in the ecological protection of grassland and rational utilization of groundwater. The project results have been rapidly promoted and applied in other areas in Inner Mongolia and Songliao River Basin. These achievements have technically supported the Ministry of Water Resources to strengthen the management of water resources in the West Liaohe River Basin of Inner Mongolia; and served as reference for the comprehensive treatment of groundwater overexploitation in typical areas of North China Plain. The achievements have also been extended to other provinces, such as Shaanxi Province, where differentiated regional management of groundwater is implemented.

Fig. 1 Controlling Groundwater Level Calculation Principles in Irrigated and Pastoral Areas

Fig. 2 Analysis of Circular Economy Development Pattern in Agro-pastoral Ecotone in Semi-arid Region

Fig. 3 Suggestions for Ecological Pattern Adjustment in the West Liaohe Plain