Clarification of land degradation phenomena and establishment of sustainable land use system in East Asia

阐明东亚土地退化现象并建立可持续土地利用体系

基本信息

批准号：
09660019
负责人：
TSUNEKAWA Atsushi
金额：
$ 1.79万
依托单位：
The University of Tokyo
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1997
资助国家：
日本
起止时间：
1997 至 1999
项目状态：
已结题

项目摘要

1° x 1° grid cells in the Asia region were classified using the datasets of vegetation, elevation, soil type, mean annual temperature and annual precipitation. Correspondence analysis was used for plotting the samples on three-dimensional space, followed by the cluster analysis for classifying all samples into ten categories. As a result, those ten land types in Asia could be mapped and the relationship between the land types and natural conditions such as vegetation, elevation, soil, mean annual temperature and annual precipitation were grasped. The result of correspondence analysis indicates that temperature and precipitation are the most important factors causing remarkable spatial structures, that is, the concentric circle centering Tibetian Highlands and South to North change from tropics to subpolar. This land classification is verified by using χ Square test to highly correspond to cultivation intensity and distribution of soil degradation.Then taking a small catchment in Sichuan Province, China that had been exposed to massive deforestation and reafforestation as a case study of land degradation, further study was made. Land cover changes during the past 50 years and actual status of bio-resources utilization were analyzed to evaluate the agricultural sustainability in a small catchment area in Sichuan Province, Southern China. This study clarified massive deforestation in the 1950's was for fuel wood supply in this area. Afforestaion in the 1970's restored the forest resources quantitatively, which means the forest cover ratio became twice as large as the average in Sichuan Province. The analysis of bio-resources utilization suggested that the nitrogen input mainly consisting of chemical fertilizer remarkably exceeds the nitrogen output in the study area.

利用植被、海拔、土壤类型、年平均气温和年降水量数据集对亚洲地区1° x 1°网格单元进行分类，利用对应分析将样本绘制在三维空间上，然后进行聚类分析。将所有样本分为十类，从而可以绘制亚洲十种土地类型图，并掌握土地类型与植被、海拔、土壤、年平均气温和年降水量等自然条件之间的关系。对应分析表明，气温和降水量是造成显着空间结构的最重要因素，即以西藏高原为中心的同心圆和从热带到副极地的变化，该土地分类是通过使用χ方检验来对应耕作强度和土壤退化分布来验证的。然后以中国四川省一个遭受大规模森林砍伐和重新造林的小流域作为土地退化的案例，进一步研究了过去50年的土地覆盖变化和实际状况。通过对生物资源利用进行分析，评估中国南部四川省一个小流域的农业可持续性。这项研究阐明了 1950 年代的大规模森林砍伐是为了该地区的薪柴供应，1970 年代的植树造林定量地恢复了森林资源。生物资源利用分析表明，以化肥为主的氮素投入强度超过了全省平均水平。研究区域的产出。