Alluvial fans are an important land resource with agricultural potential in Qinghai–Tibet Plateau. The spatiotemporal variation in land use/cover is an important indicator to understand the value of alluvial fans and protect and make scientific use of such fans. In this study, the spatiotemporal characteristics of land use/cover are determined by analysing the land use/cover changes of alluvial fans in the Lhasa River Basin (LRB) at different times, counties/districts, altitudes, and gradients. Results show that the area of cultivated land and the artificial land provided by alluvial fans for LRB has continuously increased. In 2000, 2010, and 2020, 17.72%, 21.84%, and 24.17% of cultivated land and 7.89%, 7.51%, and 25.24% of artificial land in LRB were provided by alluvial fans, respectively. At all altitudes and slopes, cultivated land and artificial land are increasing but the increasing part is basically due to the massive loss of grassland. The spatiotemporal changes in all land use/cover types of alluvial fans were dominated by human activities, although they were also influenced by natural factors to some degree.

Soil erosion is a significant global environmental issue, especially in important agricultural areas. This study focuses on the Huangshui River Basin in the Qinghai–Tibet Plateau from 2000 to 2022. The soil erosion intensity, spatiotemporal changes in soil erosion rate, and its socio-economic influencing factors at three spatial scales (basin, city, county) were analyzed. The results show that slight erosion is predominant across all scales, yet there are some localized areas with more severe erosion, like Guide County and Hualong County. At the three spatial scales, the change trend in the soil erosion rate has many peaks and valleys, and peaks and valleys occur in the same year. Influencing factors vary by scale. At the basin scale, there is no significant correlation with socio-economic factors; however, at the city and county scales, multiple factors show significant correlations, like population and GDP. Based on these findings, targeted soil erosion control measures are proposed considering socio-economic perspectives. This paper can provide a scientific basis for soil erosion and ecological environment control in Huangshui River Basin.

Alluvial fans have been proven to have great utilisation potential in QTP, but to what extent they are suitable for agricultural development is unknown. Therefore, using the alluvial fan in the Lhasa River Basin (LRB) as a case study, this paper established an evaluation system of land suitability for agriculture (LSA). Principal component analysis (PCA) and the exhaustive method (EM) were used to define the minimum dataset (MDS) and then the LSA of the alluvial fan in the LRB was evaluated using a comprehensive index of LSA. Two scientific approaches were implemented to improve the LSA using a scenario simulation. The results showed that the MDS assessed by the EA was more representative compared to the PCA. Alluvial fans with suitable grades are mainly distributed in the Lhasa River’s middle and lower reaches. Developing facility agriculture and repairing roads accessing the alluvial fans are effective approaches to improve the LSA, which can increase the suitable-grade area from 58.62% to 97.82% and 63.85%, respectively. Therefore, most alluvial fans in the LRB are suitable for developing agriculture, and under the influence of human activities, there will be more alluvial fans suitable for developing agriculture. Our research provides scientific methods for the sustainable development of land in alpine regions.