Interval Multi-Random Factorial Programming for Coupled Farmland and Water Resources Management -- A Case Study of Songhua River Watershed, China

The Songhua River Watershed (SHRW) in China has been challenged by water shortages, water pollution, water leakage, and soil erosion in recent years. In the next few decades, these problems will continue to exist and even worsen, threatening the quality of the regional ecological environment and socio-economic development. These issues must be alleviated through coupled farmland and water resources management (CFWRM) but are challenged by multiple system complexities. To fill this gap, this study developed an Interval Multi-Random Factorial Programming (IMRFP) to eliminate potential problems in SHRW and improve the reliability of the decision support process. A series of systematic CFWRM measures were applied to promote the harmonious SHRW ecological environ¬ment and social economy. For example, due to the significant contribution of agriculture to the regional economy, planting should always be a priority. As a major commercial crop, rice cultivation should be allocated the most irrigation water, followed by corn, potatoes, and soybeans. Therefore, after fully balancing the trade-off between the environment and the economy, policymakers should adopt the most reasonable proposals. Various support policies are needed to fully implement these measures in SHRW. For example, it is suggested to improve and update the construction of the water supply network in the SHRW area and appropriately change taxes and prices to follow the overall crop planting plan. The modeling solution shows that the IMRFP method can systematically optimize the allocation of water resources and farming patterns so that water shortage, water pollution, water leakage, and soil erosion in the SHRW can be alleviated.