The Spatial Distribution of Fallow Land and Its Ecological Effects in the Agro-Pastoral Ecotone of Northern China

Fallowing is a widely adopted approach for land restoration and ecological protection in the agro-pastoral ecotone of northern China. However, research on the ecological impacts of fallowing in this ecologically fragile region is still limited. With the implementation of fallow policies, it is essential to update the delineation of fallow areas to reflect current practices and ecological considerations. This study developed an index system to assess ecological vulnerability and subsequently delineated fallow areas based on urgency. The ecological effect of fallowing was evaluated using the Ecological Index. Our results show that priority and secondary priority fallow areas are predominantly located in the northern and central regions of the northern agro-pastoral ecotone, covering approximately 33.46 × 10 4 km 2 by 2023. During the implementation of the fallow policy from 2015 to 2019, the Ecological Index of each county increased, indicating improved environmental quality. However, from 2019 to 2023, the ecological status declined in all three counties, with minor changes in Guyuan County and Fengzhen City. Notably, the ecological degradation rate was faster in Huan County without the second round of fallow. These results indicate that fallowing has a beneficial effect on various aspects of the ecological environment in arid and semi-arid regions, including soil and water conservation, water network density, and vegetation coverage. Furthermore, this improvement demonstrates a sustained effect over time.