Ecological Benefit Researeh Of Different Vegetation Restoration Patterns In Arid Sandy Area

Revegetation is the key to combating land desertification expansion, easing sandstorm damage, which has been the focus of research in the ecology field, especially in arid sand areas, land degradation and desertification has become a major global environmental problem, hence appropriate revegetation mode is important to desert steppe ecosystem restoration and maintenance. This study was conducted in desert steppe in Er bukeng administrative village of Gao Shawo Town, Yanchi County, Ningxia, selecting enclosed grassland, caragana reseeding grassland, adsurgens reseeding grassland and unenclosed grassland, analyzing the impact of three vegetation restoration patterns on vegetation, soil, moisture and micro-climate aspects, using gray correlation analysis method to evaluate the ecological effects of three vegetation restoration patterns synthetically, and filter out the most suitable vegetation restoration pattern for this area, to provide the theories basis on grassland biological diversity, management practices and revegetation in arid sandy area, and lay the foundation for choosing the vegetation restoration pattern which suit to local conditions best. The main results and conclusions are as follows:(1) The height, density, frequency, coverage and aboveground biomass of grassland communities in June to September of enclosed grassland, caragana reseeding grassland and adsurgens reseeding were higher than unenclosed grassland. The richness index, Shannon-Wiener diversity index and Pielou index were:adsurgens reseeding grassland> enclosed grassland> caragana reseeding grassland> unenclosed grassland, and ecological dominance is just the opposite. Stability of plant community under different vegetation restoration patterns in descending order was:adsurgens reseeding grassland, enclosed grassland, caragana reseeding grassland and unenclosed grassland, among all, stability of plant community of adsurgens reseeding grassland was the best, but overall, plant community of three vegetation restoration patterns and unenclosed grassland were unstable.(2) Three vegetation recovery patterns reduced the soil bulk density, improved the soil structure effectively, increased the water retention and holding capacity of soil, especially adsurgens reseeding grassland was the best.0-40cm soil organic matter and available potassium content were:enclosed grassland> caragana reseeding grassland> adsurgens reseeding grassland>unenclosed grassland, soil total nitrogen and available nitrogen content were:adsurgens reseeding grassland> caragana reseeding grassland> enclosed grassland> unenclosed grassland, soil available phosphorus was:enclosed grassland> adsurgen reseeding grassland> caragana reseeding grassland> unenclosed grassland, soil total salt content and pH value of unenclosed grassland was the highest.(3) The changes of air temperature of different vegetation recovery patterns in decreasing order was unenclosed grassland, caragana reseeding grassland, enclosed grassland and adsurgen reseeding grassland, reached peak value at 14:00, showed a single peak curve; the changes of relative humidity was:adsurgen reseeding grassland> enclosed grassland> caragana reseeding grassland> unenclosed grassland, showed "V" type change curve from 8:00-20:00; the changes of surface temperature and underground 0-5cm,5-10cm,10-15cm and 15-20cm soil temperature were the same as:unenclosed grassland> caragana reseeding grassland> enclosed grassland> adsurgen reseeding grasssland, the maximum point of surface temperature appeared earliest.(4) Soil moisture of different recovery patterns grassland in May to December was: unenclosed grassland> caragana reseeding grassland> enclosed grassland> adsurgen reseeding grassland, the fluctuation of topsoil was obvious with the changes of precipitation; with the increased of soil depth, the soil moisture variation coefficient of different recovery patterns grassland gradually decreased; with the increased of soil depth, the soil moisture of enclosed grassland and adsurgen reseeding grassland increased, the soil moisture in deep soil layers of caragana reseeding grassland relatively lower. Soil moisture of three vegetation recovery patterns grassland and unenclosed grassland in May to July and November to December were formed negative balance, in August to October were formed positive balance, and the positive balance and negative balance of unclosed grassland were most obvious.(5)The degree of association of different vegetation restoration patterns grassland in descending order was:enclosed grassland> adsurgen reseeding grassland> caragana reseeding grassland> unenclosed grassland, hence the analysis from the various structural and functional indicators, the improvement effect of enclosed and adsurgen reseeding patterns were better, which are worth of popularizing vegetation restoration measurement in arid sandy area.