Is marginalised cultivated land on the Tibetan Plateau suitable for production or ecology? An example from the northeastern Tibetan Plateau

In the ecologically fragile alpine area of the Tibetan Plateau, some marginalised cultivated lands have more serious conflicts related to agricultural production and ecological protection than others; thus, it is of practical significance to explore the rational use of marginalised cultivated lands. In this study, Xining City and Haidong City in the northeastern part of the Tibetan Plateau were taken as the study area. Marginalised cultivated land was identified, and the vegetation photosynthesis model was used to evaluate its production function. Ecological function was evaluated in terms of soil retention, landscape connectivity and habitat maintenance. The rational use pathways of marginalised cultivated land were derived through statistical analysis and aggregation model analysis. The results showed that there were 183,489.19 ha of marginalised cultivated land in the study area; the average value of production function of marginalised cultivated land was approximately 70% of that of nonmarginalised cultivated land, and its various ecological functions reached 93.64%-117.98% of that of nonmarginalised cultivated land. In general, the distribution of production functions decreases from northwest to southeast, and the ecological functions are high in the middle and low in the surroundings. A comprehensive analysis of the production and ecological functions of marginalised cultivated land can provide a reference basis for the rational formulation of cultivated land protection policies and ecological protection policies.