1990—2019年石漠化区耕地时空特征及成因分析——以富源县为例

针对石漠化区耕地变化研究存在时间、空间尺度有限的问题，本文以富源县为例，基于1990、2000、2010和2019年4期的Landsat遥感数据，应用多特征与随机森林相结合的分类方法提取耕地，运用耕地覆盖度、耕地类型转化、坡度分区统计分析了近30年(1990—2019年)耕地时空变化特征，并讨论了耕地变化的原因。结果表明，1990—2019年富源县耕地面积呈先增加(1990—2010年)后减少(2010—2019年)的态势；耕地面积主要来源和转化类型均以林地和草地为主，林地最多；主要分布在北部5个石漠化面积较少的乡镇，以缓坡区为主；耕地覆盖度呈现低-高-低的过程，陡坡区耕地变化率在不同时段差异明显。近30年富源县耕地变化是在石漠化独特的地理环境下，由人口、经济、政策、交通等因素共同作用而形成的。本文的结论可为评估石漠化区域生态安全和粮食安全提供数据支撑。

Spatial-temporal characteristics and driving forces of the cropland in rocky desertification area from 1990 to 2019: taking Fuyuan county as an example

Aiming at the problem of limited time and space scale in the study of cropland change in rocky desertification area, this paper takes Fuyuan county as an example, based on Landsat remote sensing data from 1990, 2000, 2010, and 2019, uses the classification method of multi-feature and random forest to extract cropland, uses cropland coverage, cropland type conversion and slope zonal statistics to analyze the characteristics of the spatial-temporal cropland change in the past 30 years (1990-2019), and discusses the driving forces for cropland change. The results show that the cropland area in Fuyuan county increased firstly (1990-2010) and then decreased (2010-2019). The main sources and transformation types of cropland area are woodland and grassland, with woodland being the most. It is mainly distributed in five towns with less rocky desertification area in the north, and mainly in the gentle slope area. The cropland coverage show a process from low to high to low, and the cropland change rate in the steep slope area vary significantly in different periods. The cropland change in Fuyuan county has been formed by the combined effects of population, economic, policy, and transportation factors under the unique geographical environment of rocky desertification area in the past 30 years. The conclusions of this paper can provide data support for the assessment of ecological security and food security in rocky desertification area.