Knowledge Resource Center for Ecological Environment in Arid Area
| LAI表征植被水土保持功能及恢复度研究 | |
| 孙佳佳 | |
| 出版年 | 2010 |
| 学位类型 | 硕士 |
| 导师 | 史学正 |
| 学位授予单位 | 中国科学院大学 |
| 中文摘要 | 水土流失是我国各种生态问题的集中反映，又是导致生态进一步恶化以及贫困加剧的根源。我国南方红壤区总面积203万km2，占全国土地总面积的21%，是南方面积最大、水土流失最严重的区域，其局部地区曾一度成为我国的“红色沙漠”。近年来，随着水土保持部门和林业部门造林护林措施的落实，各省森林覆盖率均有明显增加，部分地区达50%以上，有的已超过70%，而与之对应的是，我国水土流失状况依然严重。这是由于林下土壤裸露程度高，仍会发生中度、甚至强度以上的水土流失。因此，选择较合理的植被指标，并对植被的恢复程度做出客观评估，对提高植被水土保持效益评价精度具有重要理论与现实意义。\n 本研究基于福建省长汀县河田镇12个土壤侵蚀试验小区2007年至2009年3年的降雨、径流、泥沙数据及各小区的植被叶面积指数（LAI）、植被覆盖度（VFC）资料，利用对比与统计分析等方法，研究了2种植被覆盖类型（纯马尾松林、马尾松林草）和不同覆盖度（80%、60%、45%、30%、15%、5%）的红壤水土流失特点，探讨了LAI与VFC定量表征水土流失关系的稳定性和可靠性，以及无明显侵蚀状态的植被指标。调查了草地、灌木林、针叶林、针阔叶混交林和阔叶林5种植被，并对全县遥感影像进行反演，评估长汀县植被状况。主要结论如下：\n （1）与裸地比较，马尾松纯林对径流的减少作用不明显，但在一定程度上减少了土壤侵蚀量；马尾松林草覆盖可以有效地减少径流25%左右，减少土壤侵蚀90%以上，林草结合的植被覆盖结构具有更强的水土保持功能。因此，水土保持生物措施，更应注重植被的层次结构以及地表草覆盖的组合功能。\n （2）对于相同的植被生长过程，LAI与VFC所反映出的年度变化特征存在差异，且峰值的出现和维持不同步。以LAI表征马尾松纯林和马尾松林草2种植被覆盖类型的土壤侵蚀模数，都能达到显著水平，而以VFC表征的土壤侵蚀模数，仅纯马尾松林覆盖类型达到了显著水平。因此，以植被结构指标LAI来表征土壤侵蚀模数，其关系将更为稳定和可靠。土壤侵蚀模数（f），草叶面积指数（x）、林叶面积指数（y）构成的三维模型为f＝－3877.6x－2880.6y＋4953.6。其中，无明显侵蚀状况（土壤侵蚀模数为500 t • km-2 • a-1）的林与草叶面积指数之和最大值为1.5。\n （3）基于长汀县植被（草地、灌木、针叶林、针阔叶混交林、阔叶林）的样区调查，本研究建立了叶面积指数与植被指数NDVI的单变量LAI估算模型及多变量LAI估算模型。比较两者精度后，选用多变量LAI估算模型进行评估。结果表明，长汀县中部地区叶面积指数值较低，全县约20% 小于15°的红壤坡面存在林下水土流失现象，且主要分布在河田镇、策武乡、濯田镇、三洲乡及涂坊镇等地区，该区植被恢复程度约为50%。 |
| 英文摘要 | Soil erosion is a focus of various ecological problems in China, and a rootstock of ecological deterioration and poverty accumulation. The red soil area in SE-China, 21% of total land area in China, had once become a red desert in some regions for serious vegetation deterioration. With forest planting and conservation by forestry and soil and water conservation departments of late years, forest-coverage rate had increased obviously in this area that some even exceeded 70%. However, soil erosion still takes place in forest, for the bareness of under-forest soil without close-cover of vegetation. Therefore, choosing a reasonable vegetation index is critical to higher precision of appraisal of soil and water conservation. \n In this study, an experiment of twelve plots (5m×20m) was set up on the red soil hills in Changting of Fujian Province, South China. These plots were under two types of vegetation cover (pure forest and forest-grass) separately and had six levels of vegetation coverage (80%, 60%, 45%, 30%, 15% and 5%). Parameters of leaf area index (LAI), vegetation fractional coverage (VFC), rainfall, runoff and sediment were measured during the period of 2007 to 2009. Using the statistical analysis method, characteristics of soil erosion under different vegetation covers various in coverage in the region were studied, soil erosion quantification by LAI and VFC was analyzed for stability and reliability, and the vegetational cover of no obvious corroded condition. Investigated 5 types of vegetation cover (lawn, scrub forest, coniferous forest, needle broad-leaf mixed forest, foliage forest) in the field, combined with remote-sensedly inversion of vegetation structures, and evaluate the Changting County vegetation condition. The main conclusions are presented below:\n (1) Compared to the control plot, pure Pinus massoniana forest did decrease soil erosion modulus to a certain extent, but runoff insignificantly. In contrast, the mixture of forest-grass cut runoff by 25% and soil erosion modulus by up to 90%, suggesting that the vegetation fraction of forest-grass is more effective in soil and water conservation.\n (2) There exist some differences which leaf area index and vegetation fractional coverage reflects regarding the same vegetation process, for instance, the peak value and the maintenance. The use of LAI to characterize soil erosion modulus under the two types of vegetation cover is able to reach the level of significance (P<0.05), while the use of VFC is but only under the forest-grass cover. Therefore, it is advisable to choose LAI to characterize soil erosion modulus to evaluate soil and water conservation for more stable and reliable results. The three-dimensional model building of the soil erosion modulus (f), grass LAI (x) and forest LAI (y), that is, f =-3877.6x-2880.6y+4953.6, the maximum LAI value of tree combined with grass is 1.5 under not obvious corroded condition (soil erosion modulus is 500 t • km-2 a-1).\n (3) Based on investigation of the Changting County vegetation in the field (lawn, bush, coniferous forest, needle broad-leaf mixed forest, foliage forest), establishes leaf area index and NDVI single-variable LAI estimate model and the multi-variable LAI estimate model, and selects the multivariable LAI estimate model to use after compared precision. Results indicate that LAI value is low in the middle of Changting County, about 20% below 15° sloping field exist under-forest soil erosion. These are widely distributed in Hetian, Cewu, Zhuotian, Sanzhou, and Tufang. |
| 中文关键词 | 水土保持功能 ; 叶面积指数 ; 植被覆盖度 ; 土壤侵蚀与水土保持 ; 植被恢复 |
| 语种 | 中文 |
| 国家 | 中国 |
| 来源学科分类 | 水土保持与荒漠化防治 |
| 来源机构 | 中国科学院南京土壤研究所 |
| 资源类型 | 学位论文 |
| 条目标识符 | http://119.78.100.177/qdio/handle/2XILL650/286861 |
| 推荐引用方式 GB/T 7714 | 孙佳佳. LAI表征植被水土保持功能及恢复度研究[D]. 中国科学院大学,2010. |
| 条目包含的文件 | 条目无相关文件。 | |||||
| 个性服务 |
| 推荐该条目 |
| 保存到收藏夹 |
| 导出为Endnote文件 |
| 谷歌学术 |
| 谷歌学术中相似的文章 |
| [孙佳佳]的文章 |
| 百度学术 |
| 百度学术中相似的文章 |
| [孙佳佳]的文章 |
| 必应学术 |
| 必应学术中相似的文章 |
| [孙佳佳]的文章 |
| 相关权益政策 |
| 暂无数据 |
| 收藏/分享 |
除非特别说明，本系统中所有内容都受版权保护，并保留所有权利。
