【作者】 邵景安；

【导师】 魏朝富； 谢德体；

【作者基本信息】 西南大学 ， 农业资源利用， 2006， 博士

【摘要】 土地利用变化作为全球变化的主要动因，目前已引起全球变化研究的广泛关注。但关于土地利用变化的轨迹及采取何种措施可以缓解由相应土地利用变化所诱导的生态环境问题等方面，在很大程度上，仍然未能很好解决。换句话说，虽然在理解土地利用变化现代过程中，大量研究结果已经被获得，但大部分文献仍然未能阐明土地利用变化的具体轨迹，未能解决土地利用变化的尺度依靠问题。过去近20年，我国陆续开展一些主要有关土地利用变化的研究项目。但这些研究主要集中在中国的东北、东南和北部区，很少对中国的西南山区尤其重庆付太多的注意。当然，土地利用变化不可避免地产生一定的生态与社会影响，而当这些影响累计超过区域生态环境的容忍限度时，突发事件就会出现。目前，合适的土地管理实践，对管理丘陵坡地土壤水和稻田土壤养分和有机碳可以提供有效的方法，已被广泛接受。但对于坡地土壤水，更多的兴趣出现在干旱、半干旱和半湿润区。而对于土壤养分和有机碳，旱地土壤和不同功能间土地转换或短期单一的管理实践对它们的影响被强调。很少知道，在微观耕作尺度上，长期土地管理实践对湿润区丘陵坡地土壤水和稻田土壤养分和有机碳的影响。而且，在宏观区域土地利用变化背景下，局地土地管理实践对土壤水、养分和有机碳的影响更是很少知道。 本研究的目标是，在中国西南山区，识别土地利用变化的轨迹，决定不同土地管理实践对土壤水、养分和有机碳的影响，厘定合适的土地利用方案，推荐有效的管理实践。研究包括两个部分：不同功能间土地利用转换和同一功能内土地利用修改对土壤水、养分和有机碳的影响。前者涉及了遥感数据、统计数据和农户调查数据，而后者则主要使用了田间或实验监测数据。对于坡地土壤水，试验包括6个处理：①横坡耕作(Cross-sloping tillage(CST))、②横坡耕作+有机肥(Cross-sloping tillage with organic manure(CST／OM))、③横坡耕作+秸秆覆盖(Cross-sloping tillage with straw mulch(CST／SM))、④等高垄作(Contour ridge culture(CRC))、⑤等高垄作+有机肥(Contour ridge culture with organic manure(CRC／OM))、⑥等高垄作+秸秆覆盖(Contour ridge culture with straw mulch(CRC／SM))。对于稻田土壤养分和有机碳，实验涉及4个处理：①常规平作+水稻-休闲轮作(Conventional tillage(rice-fallow)(CT／RF))、②常规平作+水稻-小麦轮作(Conventional tillage(rice-wheat)(CT／RW))、③垄作免耕+水稻-休闲轮作(No tillage and ridge culture (rice-fallow)(NTR／RF))、④垄作免耕+水稻-小麦轮作(No tillage and ridge culture(rice-wheat)(NTR／RW))。结果表明： (1) 研究区土地利用变化呈现显著的区域异质性，不管是土地转化的速度还是方向。对于两个时段，研究区土地利用变化呈现显著的不同的态势，分别拥有占研究区总面积18.37％和4.18％的斑块发生了利用方式的变化。在1986-1997年间，耕地被用为建设用地、草地和未利用地被开发为耕地和林地组成研究区三大土地利用格局。而在1997-2005年间，耕地被退为林地、耕地被用为建设用地、耕地转换为水域和未利用地开发为耕地和林地是研究区主要的土地转换类型。就土地利用转更多还原

【Abstract】 Land use change is one of the primary causes of global environmental change, and has caused many concerns of global change researches. But, the questions of what the trajectories of land use change and which measures mitigate environmental issues resulted from corresponding land use change remain largely unanswered. Despite that various results in understanding land use change have been achieved, most published cannot figure the concrete trajectories of land use change, and scale-dependence of land use change cannot be resolved as well. In China, several major land use change projects have been initiated in recent two decade. However, most of them have mainly focused on the North-East, South-East and North regions of China. Few studies of land use change have paid more attention to southwestern mountainous areas, China, particularly in Chongqing. Certainly, land use change inevitably results in certain ecological and social effects. Moreover, shock events will occur, when the concentration of these effects are excessive eco-environmental threshold. Currently, appropriate land management practices have universally considered that provide alternative methods for managing slopeland soil water and paddy soil nutrients and organic carbon. For slopeland soil water, more interests were made in arid, semi-arid or semi-humid regions. As for soil nutrients and organic carbon, dry farming land soils or the effects of different function land transformation or short-term and single soil management practices on them were focused on. Little is known about, at a microcosmic cultivation scale, long-term effects of land management practices on hilly slopeland soil water in humid regions, and soil nutrients and organic carbon in paddy regions. Furthermore, under the background of regional land use change, the effects of local land management practices on soil water, nutrients and organic carbon are even more poorly understood.The goal of this study is to identify the trajectories of changes in land use, measure different land management practice effects on soil water, nutrients and organic carbon, and develop proper land use scenario and recommend appropriate management practices in mountain landscapes, southwestern China. The study included two components, i.e., land transformation to a different function and effects of land modification within a function on soil water, nutrients and organic carbon. The former involved remote sensing data, statistics data and household interview data, while the latter used field or experiment monitoring data. For slopeland soil water, experimental plots were subject to the following treatments: Cross-sloping tillage (CST); Cross-sloping tillage with organic manure (CST/OM); Cross-sloping tillage with straw mulch (CST/SM); Contour ridge culture (CRC); Contour ridge culture with organic manure (CRC/OM); Contour ridge culture with straw mulch (CRC/SM). For paddy soil nutrients and organic carbon, four treatments, conventional tillage (rice (Oryza sativa L.)-fallow) (CT/RF), conventional tillage (rice-wheat (Triticum aestivum L.)) (CT/RW), no tillage and ridge culture (rice-fallow) (NTR/RF), and no tillage and ridge culture (rice-wheat) (NTR/RW) were used. The results indicated that:(1) In study site, land use change presented pronounced regional heterogeneity for two stages, regardless of the speed or direction of land transformation. The patches possessing about 18.37% and更多还原