Uncertainty in nature and human society affect pollution control efficiency and the rationality of the scheme of spatial optimization layout of best management practices (BMP) for agricultural non-point-source (NPS) pollution treatment. Based on this idea, the study innovatively develops a mathematical model that integrates soil and water assessment tool (SWAT) model and interval fractional programming. The advantage of the model are the following: (1) ability to process a BMP spatial optimization layout in watershed in uncertain situations, (2) ability to effectively reflect the uncertain factors involved in the scheme without having to set all the variables as uncertain factors, and (3) results are in the form of schemes in upper and lower limit scenarios, thereby reflecting the limit of uncertainty impact on the schemes.
The results of this study can provide decision-makers with a wide range of optional schemes. This study examines how to set up the BMP spatial optimal layout scheme for agricultural non-point-source pollution treatment under the influence of uncertain factors. The proposed method is universal and can be extended to other cases.