三峡库区农村宅基地复垦耕地地力评价*--以重庆市涪陵区为例

农村宅基地复垦后补充的耕地应兼顾数量和质量,对其进行耕地地力评价可以为全面掌握复垦后耕地地力情况,为复垦耕地的后续培肥、利用及管理提供依据。本文以三峡库区的涪陵区为研究对象,随机采集665个宅基地复垦片块的土壤样品,选取16项参评指标,运用层次分析法、模糊数学法并结合GIS地统计学空间分析功能,综合评价了宅基地复垦后的耕地地力水平及空间分布。结果表明:耕地地力平均等级为3.03等,处于中等水平;3等地最多,占总样本数的52.18%;其次为4等地和2等地,1等地和5等地分布最少。从空间分布来看,由于区域内存在地形地势、自然条件、土壤类型的差异,样点乡镇内部各等级耕地均有分布;沿江、坪上、后山区的平均耕地等别为2.82等、3.15等和3.19等,耕地地力基本沿地形地势、海拔高度的增高呈沿江、坪上、后山区域依次递减的趋势。在提升耕地地力上沿江区应着重改善耕地的灌排和路沟条件;坪上区应注重调整土壤的p H和提高有效磷含量;后山区需增加耕层厚度,提高宅基地拆除物的利用,减少土壤中砾石含量。

Evaluation of farmland productivity after rural homestead reclamation in the Three Gorges Reservoir Area - A case study of Fuling District, Chongqing City

Supplementation of farmlands after rural homestead reclamation should take into account land quantity and quality. The evaluation of farmland productivity can provide the basis for comprehensively grasping farmland productivity after reclamation and subsequent fertilization, utilization and management. Using Fuling District of Chongqing City in the Three Gorges Reservoir Area as a case study, 665 soil samples from reclaimed homestead pieces of land were randomly collected. Then 16 participatory indexes were selected using AHP and fuzzy method combined with GIS geostatistical spatial analysis functions to evaluate farmland productivity grades and spatial distribution. The results showed that the average grade of farmlands was 3.03, at the middle level. Grade 3 sample number was most, accounting for 52.18% of the total number of samples. This was followed by grade 4 and grade 2, and then grade 1 and grade 5 were the least. From the spatial distribution, differences were noted among the regions due to topography, natural conditions and soil type. All the grades were distributed within sampled townships. The average grades of riversides, level ground and mountain regions were respectively 2.82, 3.15 and 3.19. Farmland productivity of riversides, level ground, mountain regions (basically along topography), increase in altitude declined in trend. As riverside areas improved farmland productivity, focus should be put on improving farmland irrigation, drainage ditches and road conditions. Aerodrome areas should focus on adjusting soil pH and increasing soil phosphorus content. Then mountain regions needed to increase topsoil thickness, improve the utilization of homestead demolitions by reducing soil gravel content.