Impacts of droughts on agricultural and ecological systems based on integrated model in shallow groundwater area.

Agricultural and ecological developments are increasingly paid attention in light of climate change. It is expected to comprehensively macroscopically control agricultural and ecological developments in shallow groundwater area that ecology is closely related to agricultural development. This study synthesizes multi models, including process-based crop growth model, water status model of shelterbelt, and vegetation-soil-groundwater interactions to identify responses of crops, shelterbelt, and natural vegetation to different level droughts. Obtained results show that the rank of vulnerabilities to droughts is: maize (the most vulnerable crop) > wheat > sunflower > shelterbelt (the least vulnerable vegetation). Under three drought scenarios, the natural vegetation biomass is all in stable states that fluctuations of groundwater salinity and precipitation cannot largely change the natural vegetation biomass. The natural vegetation biomass in equilibrium states is decreased by 4.08 % and 9.19 % respectively when available irrigation water is reduced to 70 % and 50 % levels. The results indicate that controlling and decreasing initial soil salt content before crop growth may be an effective way to avoid the decrease in the yield loss caused by salinization. It is suggested that vulnerable crops and the possible evolution of natural vegetation towards degradation in extreme droughts should be concerned and taken certain measures. This study also implies that optimizing planting structure is a possible strategy to improve adaptabilities to droughts and decrease economic losses. The established model contributes to provide an effective approach to handle large-scale decision-making problems about comprehensively developing agriculture and ecology in changing environments. Obtained results can provide reference strategies for managers to achieve sustainable development.