岩溶山地撂荒地演变研究—以郎溪槽谷区为例

中国山区面积广、坡耕地比重大,耕地撂荒不仅关系到山区农地的合理利用和可持续发展政策的制定,还对生态环境问题产生影响。因此,本文以2004年、2010年、2014年、2017年朗溪槽谷遥感影像等为数据源,通过景观格局指数、缓冲区分析及结合槽谷高程分析朗溪槽谷撂荒地分布格局、演变规律、驱动机制和撂荒效应。结果得出:耕地撂荒主要发生在朗溪槽谷两侧山坡坡耕地,谷底平坦地区撂荒现象较少。以2014年为分界点,2004～2017年朗溪槽谷撂荒地呈现出先增加后小幅度减少的变化趋势,且槽谷两侧坡耕地撂荒变化较为明显。简而言之,经过数据分析后归纳出朗溪槽谷区耕地撂荒的演变阶段及演变模式,引起其撂荒现象的原因主要是农户人口减少导致聚落的逐渐空心化,其次是耕地所处的海拔以及政策影响。耕地撂荒后呈多样化演变,土地逐渐集约化利用与耕地撂荒后演变为林灌草并存,生态环境得到一定改善,这对乡村产业发展、美丽乡村与生态农村建设起着重要意义。

Study on the Evolution of Abandoned Land in Karst Mountains: A Case Study of the Valley of the Troughs

China has a large area of mountains and has a large proportion of sloping arable land. The abandonment of arable land not only impacts the rational use of agricultural land in mountainous areas and the formulation of sustainable development policies, but also affects the ecological and environmental issues. In this paper, remote sensing images of Langxi trough valley in 2004, 2010, 2014 and 2017 were taken as the data sources to analyze the distribution pattern of abandoned land, evolution law, driving mechanism and the associated effects through the landscape pattern index, buffer analysis and the trough valley elevation. The results showed that, arable land abandonment mainly occurs in hillsides and arable land on both sides of the Langxi trough valley. Taking 2014 as the demarcation point, from 2004 to 2017, the abandoned land of the Langxi Trough Valley showed a trend of first increase and then a small decrease, and the changes of the slope farmland abandoned on both sides of the Trough Valley were more obvious. In short, after analyzing the data, the evolutionary stages and patterns of arable land abandonment in the Langxi trough valley are summarized. The main reason for the abandonment is the decrease in the number of farmers and the gradual hollowing of settlements, followed by the elevation of the arable land and policy implications. The cultivated land was diversified and evolved. The land gradually became intensive and the cultivated land was degraded into the coexistence of forest, bush, and grass. The ecological environment was improved to a certain extent, which played an important role in the development of rural industries, the construction of beautiful rural areas, and ecological countryside.