| Grassland desertification is a great ecology problem that was concerned by domestic and foreign experts. The increasingly worsening of grassland ecosystem environment has already threaten to the the ecosystem safety of the world. In order to master the cause of deserdification and revegetation of grassland, this research combined macro and micro view together and combined field investigation and aboratory quantitative analysis together, using recovery ecology's principle and method, taking Naiman county as an example, carry on thorough analysis to the cause of grassland desertification in Mid-Eastern Inner Mongolia. The focal points is the revegetation mechanism of enclosure in the desertification grassland, the seed source effect of enclosed desertification grassland, the efficiency of high-parallel sand-barrier controlling serious desertification of grassland and the revegetation function of grassland improvement measures etc.The conclusion as following:(1) The grassland desertification of Naiman county resulted in both the changes of climate and human activities, especially irrational animal husbandry mode, the changes of climate accelerated the degradation of eco-system of grassland.(2) With the increasing of the enclosure time, species composition of desertification grassland, soil seed bank, soil physics and chemistry property all take place variety regulally. Main performanceis: ①In the on-ground plants and seed bank, the strong sand livings plant disappeared gradually, herbaceous perennid and quality grass become dominant; ②The coverage, mean height, branch number, aerial part biomass, belowground biomass of plant, species enrichness and evenness degree of plant on desertification grassland gradual increasing; ③The character of similarity in soil seed bank and species composition in different stages of enclosure in desertification grassland shows a common result. There is a high similarity between the samples which have a close enclosing time. Then the similarity becomes smaller and smaller with the increasing differences of the enclosing time; ④The regularity of variation of species composition both the seed bank and the standing vegetation are uniformly, but this regular shows some hysteresis quality for the siol seed bank. ⑤There has a distinguish correlation between the seed bank and the standing vegetation density, which can be described by secondary curves; ⑥It can decrease the coarse sand particles, increase the contents of minute sand parts in soil particle-size composition. ⑦Enclosure for desertification grassland can increase significantly the content of soil organic matter, total N, total P and total K.(3) The seed source effect of enclosed desertification grassland is dramatic, which can restore radially the seed bank around sandy grassland. In addition, the influences are fade-away gradually out of fence for about 500 meters.(4) Installation of high-banded sand-barrier in seriously desertificated grassland can accelerate revegetation to it. The result represent on following aspect: ①Increase the variation of coverage; ②Intercept seeds in sandy-driving wind, enriching seed bank; ③It can ncrease the contents of soil organic matter; ④It can decrease the coarse sand particles, increase the contents of minute sand parts in soil particle-size composition.(5) Airplane seed sowing, artificial after-culture, irrigation and fertilizer all have significant function. The result of artificial after-culture, irrigation and fertilizer indicated that line seeding, dibble seeding and broadcast all have significant function on the revegetation of deserdification grassland. The effect of line seeding is better than dibble seeding and broadcast. Irrigation measure has distinguish effect too, especially to the small area deserdification grassland. Nitrogen fertilizer, potassium fertilizer, and phosphoric fertilizer all can greatly accelerate the speed of revegetation. Nitrogen fertilizer's function is the most significant, and potassium fertilizer is secondary.
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