Impacts of land consolidation on rural human-environment system in typical watershed of loess hilly and gully region

Land fragmentation and low productivity are the prominent problems facing China's agricultural development. Land consolidation has become an important policy tool aiming at solving these problems in China. In addition, the development of land consolidation projects will inevitably have a certain impact on the local rural regional system, especially the local ecological environment and social and economic development. Study on the impact of land consolidation on the evolution of rural human-environment system is of positive significance for optimizing land consolidation model and promoting rural revitalization. Taken a typical small watershed in Yan'an city as the case study area, in this paper, we explored the impact of gully land consolidation on local human-environment system from the perspectives of land use, landscape pattern, ecological security, social response and comprehensive evaluation, based on high-resolution image data, landscape pattern analysis and field investigation. The results showed that due to the gully land consolidation, the terraces, sloping fields, shrub land and grassland at the bottom and both sides of the gully were mostly converted to high quality check dam land. Some of the shrub land were converted to more ecologically suitable native forest due to biological measures. The check dam land and forest land increased by 159.06 hm2 and 69.75 hm2, respectively. While the shrub land, grassland and sloping land decreased by 112.37, 63.26 and 59.06 hm2, respectively. In addition, the average patch area and patch cohesion index of the check dam land increased, and the function of production also improved. The landscape shape index and patch cohesion index of forestland and shrub land kept at a high level, and thus their ecological function was stable. At the watershed level, the fragmentation degree of landscape decreased, the landscape tended to be more diversified and balanced, and the anti-jamming capability of landscape and stability of ecosystem improved. Moreover, in terms of the ecological security effects, vegetation cover, ecological environment and capacity of flood control improved significantly, and soil erosion decreased significantly. However, there were still some ecological risks. And finally, human activities responded more or less to the changes of geographical environment of watershed. The scale of agricultural production, agricultural mechanization, diversity and non- agriculturalization of employment increased; but there were still some problems that needed to be addressed, such as very unitary of the structure of agriculture, the low efficiency of agriculture production. This paper suggested that more efforts should be made to innovate the rural governance mechanism of "mutual deliberation and collective action", thereby exerting the comprehensive effectiveness of gully land consolidation and promoting the transformation development and revitalization of the watershed. At the same time, this study also suggested strengthening the investigation, monitoring and evaluation of the effects of gully land consolidation on local environment so as to ensure that it produced more positive ecological effects. © 2019, Editorial Department of the Transactions of the Chinese Society of Agricultural Engineering. All right reserved.