Knowledge Resource Center for Ecological Environment in Arid Area
| 拉萨河流域耕地质量评价及时空变化研究 | |
| 其他题名 | Cultivated Land Quality Assessment and temporal change research in the Lhasa River Basin |
| 付国珍 | |
| 出版年 | 2015 |
| 学位类型 | 硕士 |
| 导师 | 尹云鹤 |
| 学位授予单位 | 中国科学院大学 |
| 中文摘要 | 本文以西藏自治区拉萨河流域耕地为研究区，根据野外调查数据、土壤普查数据、遥感影像数据等，运用3S技术，进行了研究区耕地质量评价及其时空变化分析。取得的主要成果为： （1）提出了基于跨尺度影响因子的耕地质量空间抽样方法。在典型小流域和整个流域两个尺度上，利用主要影响因子叠加图的分异性表征土壤质量的分异，在因子叠加分层内随机且均匀抽样。结果表明：基于影响因子获得的采样点代表性强，即自相关性弱、分异性强；小尺度典型小流域采样点（空间自相关系数I值为0.05，异质性值PD,H为0.42）的代表性好于大尺度的全流域采样点（I值为0.29, PD,H为0.69）；基于影响因子采样方法获得的采样点的代表性好于系统采样方法。 （2）进行了耕地质量环境因子分析。本研究以不同层次（0~20cm、20~40cm、40~60cm）土壤水分为例，运用生态学冗余分析和统计分析，筛选出影响耕地土壤水分的主要因子。结果表明：在全流域尺度上，受气候、海拔影响土壤水分呈西南-东北递增趋势，受河流侧渗补给影响，下层土壤水分高于上层；在小流域尺度上，耕地土壤水分随海拔升高及坡度增大而减少，随石砾含量增多土壤贮水能力减弱。 （3）结合上文的土壤及影响因子数据，探讨了土壤质量空间插值方法，进行了耕地质量评价及时空变化分析。从耕地自然质量分等和耕地限制因子分布两个角度分析耕地质量的大小及空间分布；分别对比2007年-2013年耕地自然质量等和1990年-2013年典型剖面点的土壤指标变化，分析近25a耕地质量变化。结果表明：耕地质量总体较低，集中分布于4-7等。其中低肥力分布于流域中下游及水库两侧，高石砾分布于高海拔陡坡度地区，水分不足分布于温和半干旱区。近25a，耕地质量总体降低，仅速效磷含量升高；而在近7a中，耕地向高海拔陡坡度扩张，新增耕地质量较低。 |
| 英文摘要 | Take cultivated land in Lhasa River Basin as an example, this paper explored the evaluation and analysis of temporal and spatial variation of cultivated land quality, taking advantage of the field sampling data, soil census data and remote sensing images by 3S technique. The main result were as follows: (1) This paper presented a spatial sampling method based on influencing factors through different scales. An overlay image staking by some main influencing factors affecting cultivated land quality was made, then random and uniform samplings were conducted at the cross-scale of typical small watershed and the whole basin. The results showed that sampling points based on main factors had strong representativeness, weak autocorrelation and strong differentiation among points were observed. Also, the representativeness of small scale sampling points, whose Moran’I value was 0.05 and PD,H value was 0.42, was much better than that of large scale, the value of Moran’I and PD,H were 0.29 and 0.69 respectively. In addition, the method of spatial sampling based on influencing factors was much superior to uniform sampling. (2) Soil quality environmental factors analysis is the basis of cultivated land quality evaluation and temporal change analysis. Main factors affecting the soil moisture were identified, using ecological redundancy analysis (RDA) and statistic analysis methods, based on data obtained by remote sensing technology and field surveys. The results showed that influenced by climate and altitude, soil moisture content in the Lhasa River basin increased from southwest to northeast, and moisture content was higher in lower soil layer than upper layer due to water supplement by lateral seepage of the river. At sub-watershed scale, farmland soil water content decreased with increasing altitude, slope, and gravel contents. (3) Based on the soil and impact factor data above, spatial prediction method of soil quality were investigated, and cultivated land quality and temporal change were analyzed. Cultivated land quality assessment were studyed from two aspects of arable land quality grading and cultivated land quality limiting factors. Cultivated land quality changes in recent 25 years were studyed by comparison of arable land quality grading in 2007 and 2013, and soil indicators changes in typical profile points in 1990 and 2013. The results showed that cultivated land quality was low overall, most of which concentrated on grading four to seven. Low nutrient area mainly distributed on the middle-lower reaches of Lhasa River basin and both sides of reservoir, and high gravel content mostly located on the region of high altitude and steep slope, with low soil moisture mainly spreading on the semiarid climate region. In recent 25 years, cultivated land quality was basically reduced, whereas rapid available phosphorus was increased. In recent seven years, arable land expanded to the high altitude steep slope with low quality of new land. |
| 中文关键词 | 耕地质量 ; 空间抽样 ; 影响因子 ; 空间插值 ; 时空变化 |
| 英文关键词 | Cultivated land quality spatial sampling influencing factors Spatial interpolation temporal and spatial variation |
| 语种 | 中文 |
| 国家 | 中国 |
| 来源学科分类 | 自然地理学 |
| 来源机构 | 中国科学院地理科学与资源研究所 |
| 资源类型 | 学位论文 |
| 条目标识符 | http://119.78.100.177/qdio/handle/2XILL650/287491 |
| 推荐引用方式 GB/T 7714 | 付国珍. 拉萨河流域耕地质量评价及时空变化研究[D]. 中国科学院大学,2015. |
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