【作者】 潘多锋；

【导师】 马玉寿；

【作者基本信息】 甘肃农业大学 ， 草业科学， 2007， 硕士

【摘要】 以三江源区高寒草甸类草地为主要研究对象,在3个亚类,7个型组,52个草地类型上进行全面的地面调查。将调查数据通过聚类分析和主成分分析得出三江源区高寒草甸退化草地等级划分标准,并以此对“黑土型”退化草地的类型和等级进行了划分,同时研究了“黑土型”退化草地的主要植被类型及其植被演替序列。本文还分析了不同退化程度草地的群落特征、土壤理化性质以及查阅相关文献提出了“黑土型”退化草地的恢复治理措施。得到以下结论:(一)以优良牧草比例、可食牧草比例、原生植被盖度、退化指示种比例、秃斑地盖度、啮齿类的危害以及土壤0～10cm有机质含量为指标对三江源区高寒草甸退化草地进行数量分类,结果表明三江源区高寒退化草地可分为5个退化级别,依次为:未退化、轻度退化、中度退化、重度退化和极度退化。通过主成分分析得到秃斑地盖度、可食牧草比例、啮齿类的危害、退化指示种的比例以及土壤0～10cm有机质含量这5个指标即可详尽表达高寒草甸退化草地的退化信息,因此上述5项指标可用来制定三江源区高寒草甸退化草地的分级标准。而在实际应用中用秃斑地盖度、可食牧草比例和退化指示种的比例3项指标就可方便、快捷、准确地判断出草地退化状况。(二)“黑土型”退化草地的界定范围是:秃斑地盖度大于40%、可食牧草比例小于35%、退化指示种超过50%、及0～10cm土壤有机质含量低于7.5%。按照坡度大小把“黑土型”退化草地分为3个类型,坡度在0～7度间的为滩地、7～25度的是缓坡地、大于25度的为陡坡地。每一类型下根据秃斑地盖度和可食牧草比例又可划分为轻度“黑土型”退化草地、中度“黑土型”退化草地和重度“黑土型”退化草地三个退化级别。其中,轻度“黑土型”退化草地的秃斑地盖度在40%~60%间、可食牧草比例为10%～15%;中度“黑土型”退化草地的判别标准是秃斑地盖度为60%～80%、可食牧草比例为5%～10%;重度“黑土型”退化草地上秃斑地盖度大于80%且可食牧草比例小于5%。治理轻度“黑土型”退化草地建议采用封育和建植半人工草地的措施,而对于中度和重度“黑土型”退化草地需建植半人工草地或是翻耕建植人工草地。(三)“黑土型”退化草地的主要植被类型有:帚橐吾+铁棒棰型群落、西伯利亚蓼+鹅绒委陵菜型群落、冷蒿+白苞筋骨草型群落、甘青微孔草型群落、甘肃马先蒿型群落、摩苓型群落和铁棒锤型群落。演替序列是从嵩草属到早熟禾属到早熟禾属、杂类草到杂类草最后演替为毒杂草为主的群落。(四)高寒草甸退化过程中地上植被与土壤状况的变化十分明显,鼠害猖獗,中多样性下降。“黑土型”退化草地产量仅为未退化草地产量的13%,植被平均盖度为45%,植物种类构成60%～80%为阔叶毒杂草,土壤有机质和养分下降剧烈,基本上失去了生态价值和牧用价值。“黑土型”退化草地植被的表观就是次生毒杂草群落,该次生毒杂草群落对草地畜牧业没有任何利用价值,并且对周边健康生态系统产生胁迫。更多还原

【Abstract】 Field investigation was roundly implemented on the 52 types grassland of 7 groups in 3 subformations of the alpine meadow in the“Three-River Headwaters”Region. The criterion classification for the alpine meadow degraded grassland and types and grade criterion of were elicited by using quantitative classification (TWINSPAN) and the DCA (Detrended Correspondence Analysis) sort-ing method.Meanwhile the most plant community and succession sequence of“black soil type”degraded grassland were studied .Also the characters of community and soil chacacters in the different degraded grassland were studied, the resume measures of the different types and degraded of“black soil type”degraded grassland were also concluded by reading correlated literatures.The results were follows:First: Quantitative classification to the alpine meadow degraded grassland in the“Three-River Headwaters”Region basiced on the index of eximious pasture proporation, esculent pasture proporation, proterozoic vegetation cover, degraded indication species proporation, bareland cover, jeopardize of rodent and organic matter proporation were studied, the result showed that there were five degraded levels of the alpine meadow in the“Three-River Headwaters”Region. The index of bareland cover, esculent pasture proporation, jeopardize of rodent,the proporation of degraded indication species and organic matter proporation could explain status of the degraded grassland with proportion of 98.769% .So we could establish the degraded criterion of the alpine meadowni the“Three-River Headwaters”Region. In practical application the index of bareland cover, esculent pasture proporation and degraded indication species proporation can differentiate status of the degraded grassland conveniently and veraciously.Second: The“black soil type”degraded grassland could be compartmentalized three types by gradient: bottomland(gradient range form 0°to 7°), slowgoing-sloping(gradient range form 7°to 25°) field and steep sloping field(gradient beyond 25°).Each type was divided into light“black soil type”degraded grassland, middle“black soil type”degraded grassland and Heavy“black soil type”degraded grassland by bareland cover and esculent pasture proporation.The bareland cover was 40 percent to 60 percent in light“black soil type”degraded grassland and 60 percent to 80 percent in middle“black soil type” degraded grassland, while it was above 80 percent in Heavy“black soil type”degraded grassland. The esculent pasture proporation in light“black soil type”degraded grassland was 10 percent to 15 percent, but only 5 percent to 10 percent in middle“black soil type”degraded grassland .It was less than 5 percent in Heavly“black soil type”degraded grassland.This paper suggested that the measures of fencing and establishing artificial grassland should be taken in order to resume the productivity of the degraded grassland.Third:The main plant community of“black soil type”degraded grassland were: Lingularia virgaurea and Aconitum pendulum, Polygonum sibiricum and Potentilla anserine, Artemisia frigida and Microula pseudotrichocarpa, Polygonum sibiricum and Pedicularis kansuensis, Morina chinensis, Aconitum pendulum. The succession sequence of“black soil type”degraded grassland were form Kobresia to Poa to Poa and weeds to weeds to noxious plant community.Forth: Upground vegetation and soil nutrient varied obviously during the degraded prosess of alpine meadow. And the jeopardize of rodent is rampancyly, plant diversity decreases rapidly.The herbage yield was only 13 percent of undegraded grassland, vegetation cover was 45 percent, 60 percent to 80 percent of its plant species were noxious plants,the nutrient and soil organic matter decreased heavily.Those noxious plants had no value to the grassland stockbreeding and threatened the health of ecosyeterm arrounding.更多还原