| This study systemtically analysis the influences of Hippophae forest to local ecological environment planted in sandstone area of Nuanshui Township in Ordos to provide theoretical basis and refrence for soil loss control in sandstone area.Mainly study on Hippophae growth status investigation and root distribution morphology characteristics study in different site conditions, manplanted Hippophae forest increase undergrowth vegetation diversity study, canopy layer closure precipitation, benefit of Hippophae forest and litter hold water ability, soil improvement benefit of Hippophae forest,energy value of Hippophae forest and utilization technology study, measurement of carbon sequestration of Hippophae forest. At last,conclusions are drawn as follows:(1) Hippophae grow fast in the third year, after the fifth year growth vigor gradually to stable.The correlation between above-ground bioass and under-ground bioass of different tree ages Hippophae in the same site condition is well.Analysis to tree hight、 crown width and ground diameter can draw that local precipitation is limiting factor to influence Hippophae growth vigor. The roots mianly distribute in0-40cm depth soil on the sandstone slope.Inspite from change law of Hippophae bioass with soil depth or distribution law of Hippophae roots diameter classes in soil, we can kown that Hippophae belong to shallow root plant.(2) There are22kinds of vegetation under Hippophae forest. The main vegetation under forest respective is Artemisia anethifolia L.、Salsola、Stipa krylovii、Thfmus serphllum L.var.asitatius kitag and Ixeris chinensis (Thunb.) Nakai, its cumlative appeared frequency is50.77%. The rare vegetation under forest is Leonurus japonicus Houtt.、 Taraxacum mongolicum Hand.、Serratula centauroides L. and Plantago depressa Wild.Enum, its cumlative appeared frequency is less than4%.With the increase of tree age, vegetation diversity index present the trend of high-low-high.(3) Under the same precipitation condition, canopy density is larger; the early loss time is longer; early loss value is larger.Canopy density is larger; the effect of delaying and decreasing runoff is stronger. In the same rainfall condition, with the increase of canopy density, total runoff depth and amount of soil erosion present decreasing trend.The total siol erosion of Hippophae forest under0.8Ⅰ canopy density increase85.44%than0.8canopy density. The Hippophae forest under0.8Ⅱ canopy density is that cutting off the aboveground part meanwhile clearing the entire litter layer. The total soil erosion of Hippophae forest under0.8Ⅰ canopy density decrease88.42%than0.8Ⅱ canopy density. Holding water amount of litter layer is increasing with tree agers.The sequence from large to low of holding water amount of litter layer is that furrow sole> slope top> gully slope. Artificial Hippophae forest can increase soil water content and porosity of sandstone soil, meanwhile can increase available N、P、K and organic matter content of sandstone soil.(4) With the increase of tree ages, Hippophae plant ash content present increasing trend. Hippophae plant ash content is about19-20KJ·g-1. The sequence from large to low of average removing ash content of each organs is that root> branch> leaf> bark.The best stumping age of Hippophae plant is8years old.The best stubble hight is10cm.Germination status of painting treatment on crops for rotation is better than no any treatments on crops for rotation.(5) The carbon content of leaf is54.72%, the carbon content of root is45.26%and the carbon content of bark is54.58%. After20years, the carbon reserve is81911.53t totally. In the course of plantation and tending, as a result of transport of seedling and fruit, water, fertilizer and other activities, carbon emission is834.60t. After20years of reforestation projects, net carbon sequestration is81077t. |
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