Identification of ecological problems and restoration zoning in the hilly red soil region of southern China

Ecological restoration of land space is one of the most important contents to promote agricultural production in recent years. The cultivated land is also one of the major carriers in agricultural space. A better tradeoff between cultivated land and forest can greatly contribute to the ecological protection and restoration. However, the agricultural land has been fragmented by rapid urbanization, particularly by the transfer of cultivated to marginal land, and the unreasonable land use. Therefore, it is very necessary to accurately identify the ecological patterns of cultivated land for the decision-making on the high-quality development and the scientific restoration of land space. Taking Jiangxi Province of China as the research area, this study aims to improve the scientific and reasonable zoning of the spatial layout during ecological restoration. The identification angles of cultivated land were set as the key points of agricultural spatial ecological diagnosis, according to the standard on Compilation of Provincial Land Spatial Ecological Restoration Planning (Draft for Comment). Some aspects were considered, including the ecological restoration functions of degraded land, the distribution scope and degree of ecological space stress caused by agricultural development, the landscape connectivity, and the negative impact on the mine ecology. The ecological cultivated land was closely related to the spatial restoration of agricultural production. Four indicators were then identified for the fragmentation of cultivated land, mine damage, soil erosion, and the conflict with ecological land. The index degree was also calculated using Revised Universal Soil Loss Equation (RUSLE), landscape index, land use transfer matrix, and GIS spatial analysis on each ecological restoration. Furthermore, the comprehensive index of ecological restoration was constructed using the combination weight. The ecological restoration of cultivated land was divided systematically, according to the division method of watershed, main ecological challenges, and restoration degree. The results show that: 1) The mild erosion of cultivated land was found in the study area during 2000-2018. The total area of soil erosion decreased by 50.98%. But the worse erosion was observed in the upper reaches of Ganjiang River, and the area around Poyang Lake. There was a great increase in the patch density and fragmentation of cultivated land, indicating the discrete aggregation tends. Specifically, the cultivated land was occupied 739.15 km2 of ecological land, such as forest land, water area, and wetland. The cumulative area (13.18 km2) of cultivated land was destroyed by the abandoned mines, such as the building materials, brick clay, and rare earth metals. 2) There was the outstanding spatial differentiation in the comprehensive index of the cultivated land during ecological restoration. Eight river basins and nine types of secondary areas were then subdivided into 38 sub-districts, according to the key restoration of soil and water conservation, the mine ecology, ecological land, and cultivated land connectivity. Two recommendations were given: 1) The Xinjiang and Xiushui basins need to strengthen the soil and water conservation, as well as the mine ecological restoration. 2) The ecological conflict remediation of cultivated land and the mine ecological restoration can be focused on the central areas of Poyang Lake, Raohe River basin, and the upper reaches of Ganjiang River. The finding can provide a strong support to the high-quality development of cultivated land in agricultural space in national land spatial planning. A scientific basis can also be offered to the ecological restoration layout of agricultural space in Jiangxi Province of China. © 2022 Chinese Society of Agricultural Engineering. All rights reserved.