This research was conducted in degraded rangeland at the southwestern edge of the Mu Us sandland, Yanchi county, Ningxia, the soil seedbank features and its relation to vegetation was analyzed using similarity analysis and ordination method, the results show that seeds within soil distribute mainly in 0~5 cm soil layer, less seeds in 6~15 cm soil layer in exclosed and non-exclosed rangeland, for seeds in exclosed soil, species richness and diversity index H are higher, while D is lower, exclosure measure, generally speaking, can increase plant species and amount of vegetation and seeds in soil, some annual plants, mesophytes and halophytes appears in the soil or surface.

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The study has shown:(1) With increasing sediment depth and the woody giblets, the total organic carbon, the extraction of benzene , the total humic acids and the unhydrolyte are enhanced, while the hydrolyte is decreasing.(2) According to the GC-MS analysis, n-alkane,n-alkan-2-ones and n-alkanones are composed mainly of long-chains,such a result is thought to be characteristic of a herbaceous input from 2300a.B.P. n-alkanones exist in the samples may be considered as the evidence of microorganisms activity.(3) It is showed that the lipids is more sensitive to the climate change than the floristic. The proxy of the pollen spore of the peat stratum is different from the normal environment proxy. It is one of the main reasons that the sensitivity difference of the bog vegetation reacting to the climate isn't accordant with the log of the fat molecule fossil and biology fossil.(4) The transformation of the peat organic carbon is under the influence of temperature,acidity,organic material constituting, etc, and it showed the up-trend with the depth. In the short-term scale, the conversion of the peat organic carbon is effected by seasonal water,regional climate and vegetations; while in the long-term scale, it is controlled mainly by the climate.(5) According to the comparing the orderliness of organic compound,vegetation giblets with the depth to the characteristics of the peat molecule fossil with the section, in the development of this peatmire, 1500a B.P（210cm）is regard as the borderline of the late Holocene, the keynote of the front period is warm with several cold fluctuations, and the trend of the back period is dry and cold although there were several fluctuations.

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Vegetation ecotype tend to be xerophyte and even hyper-xerophyte and finally replaced by annual plant. Community structure and species diversity also decrease as the ecological environment worsen, In this process, the height, coverage and biomass decreases by 56.6%、 80.8% and 74.2% respectively compared to steppe, and the indices of species richness, diversity and evenness decrease by 76.4%中文字暮-色哟哟、 56.7% and 32.0%, but β diversity indices increase by 14.6 times, especially the decease of species gregariousness and the breadth and overlay of species Niche shows that grassland tend to be more sandy and vegetation retrogression succession take place.

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The vegetation trimmer of the invention has improved balance and inertia, making it easier for a user to operate, and in certain embodiments thereof can be made more compact than a conventional vegetation trimmer having a flexible drive shaft for greater ease of shipping and storage.

本發(fā)明的植物修剪器具有改進(jìn)的平衡和慣性，從而使之更易于使用者操作国产午夜天堂免费观看AV，并且在其特定實施例中可以比具有柔性驅(qū)動軸的現(xiàn)有植物修剪器更加緊湊以更易于裝運和存儲国内揄拍国内精品人妻图片。

On the basis of a great deal of information, several general problem on land sarface process parametrization for a global circulation model and its history of development are described. The Bucket model, EARTH, ISBA and SiSPAT models are respectively expounded, and the situation of studies on land surface process parametrization is summarized. China is a participating country of the international geosphere-biosphere program and the study on circulation of global energy and moisture, and has put forward some valuable soil-vegetation-atmosphere models for land surface process parametrization. which results in effective studies on vegetation indexes.

在大量資料基礎(chǔ)上，敘述了大氣環(huán)流模式陸面過程參數(shù)化方案的一般問題及其發(fā)展歷程超碰97自慰，分別闡述了水桶模式免费观看国产噜噜视频网站、EARTH模式、ISBA模式和SiSPAT模式麻豆精品视频在线；總結(jié)了在陸面過程參數(shù)化方面的研究狀況欧美性爱高潮视频，我國參與了國際地圈生物圈計劃和全球能量與水分循環(huán)的研究，特別是在陸面過程的參數(shù)化研究方面XXXXWWW视频欧美，提出了一些有價值的土壤—植物—大氣模式国产精品视频网站免，對植被指數(shù)進(jìn)行了有成效的研究。

Under the invariable air temperature and sunlight, the relatively high precipitation influences on vegetation mainly distribute in semi-arid and arid regions. The analysis on lag correlation coefficient indicates: vegetation activities are mostly influenced by precipitation and the influence has a delay of 20 days.

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This study deals with butterfly diversity and conservation of rare as well as insect fauna species in Baishuijiang Natural Reserve in Gansu Province. The research includes field investigation, observation at certain time and places, captive breeding in experimental area etc. Butterfly species diversity in Baishuijiang Natural Reserve and variation regulation of butterfly diversity in different areas are studied. The relationof butterfly diversity with environmental factors such as vegetation destruction, human disturbance are strenthened in Bifeng Gully. The biology of two rare butterfly species is studied. Meanwhile, this study deals with insect α-diversity and β-diversity in Baishuijiang Natural Reserve and inquire into the mechanisms of ecological control by protecting and recovering vegetation. The research includes field capture with sweeping net, light trap, transect investigation.

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Utilizing Multivariate Regression Modeling and Spectral Derivative to establish five function pattern cotton dry matter accumulation modeling based on Ratio Vegetation Index and Normalized Difference Vegetation Index,all correlation coefficient is highly positive(α=1%,n=96),based on RVI modeling has a higher precision than NDVI does,hyperbolic curve fitting,exponential curve fitting and logarithmic curve fitting have further improved analysis against cotton dry matter accumulation.

利用北疆8個棉花主栽品種(其中2個棉花品種設(shè)4水平種植密度)的各生育期冠層高光譜數(shù)據(jù)，經(jīng)多元統(tǒng)計分析與光譜微分處理久久午夜片一级A片，建立了基于比值植被指數(shù)和歸一化植被指數(shù)的5種函數(shù)形式的棉花干物質(zhì)積累估測模型www.swag，相關(guān)系數(shù)均達(dá)到了極顯著水平(α=1%，n=96)日韩午夜无码A级毛片。

The result shows that the outcome based on Neilson model is conformable to the one of natural vegetation on Big Jinsan Island surveyed by Shanghai Natural Musium exports in the recent years ; the contrast result between the climate diagram in Jinshan region and the classic one about terrestrial vegetation is conformable as well as Neilson model.

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In Zigui Country, the numbers of Nematoda, Acarina and Collembola individuals were not much affected by habitat and elevation, while in Wanxian Country, the numbers of Acarina and Collembola were by elevation. In Shennongjia region, distribution of Nematoda varied significantly with vegetation. Acarina and Collembola were widely distributed in various soil layers under different vegetation, whereas the number of Acarina in the litter layer varied significantly with habitat and elevation.

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