| The Yellow River Delta is China’s three major Delta and key development areas, has animportant strategic position in the development of the Bohai Sea region. In recent years, theYellow River Delta Point to ecological and environmental problems due to soil salinizationand drought stress is more prominent, to some extent affected the process of vegetationrestoration and ecological reconstruction of the region, resulting in the regional vegetationflora vegetation types, structure simple, forming a single. Therefore, repair the Yellow RiverDelta soil-tidal saline dampness to rebuild the coastal green ecological barrier, has become atop priority. Mainly after restoration and ecological restoration technology is one of the mainmeasures of the Yellow River Delta fragile ecosystems reconstruction.The soil enzyme is a protein nature biocatalyst is an active participant of the soilbiochemical processes involved in the process of soil organic matter decomposition, synthesisand transformation as well as the reduction and oxidation of inorganic substances.In this study, the Yellow River Delta and different salinity of soil salt content fragileecological zones shelterbelt system degradation serious ecological and environmentalproblems, select there shelterbelt types in the Yellow River Delta (mixed forest of trees, pureforests and shrubbery) as object of study, with grassland and bare land as a control, analysisthe soil hydrological properties characteristics, soil nutrient content, soil microbes quantityand soil enzyme activity and other indicators, to explore different vegetation types to improvethe ability of the soil properties, to select this site conditions stand structure and businessmodel of the optimum protection forest, provide a theoretical basis for the saline-alkali soilimprovement building and sustainable development of coastal shelterbelt system. Theexperimental results and the main conclusions are as follows:(1) On the growth of the stand, the diversity of understory herbaceous plants and litteraccumulation, showed that the mixed forest of trees is the optimal, pure forests followed, andthe grassland worst;(2) Whether it is during the dry season or the rainy season, afforestation, increase soil urease, catalase and invertase activity, while reducing soil polyphenol oxidase activity.Compared with the bare land, including changes of the mixed forest of trees on soil enzymeactivities maximum, the smallest grassland;(3) Aspects of soil hydrological properties characteristics, afforestation, significantlyreduced soil bulk density, increased soil porosity, increases the soil’s water holding and waterstorage values, improved soil aeration and permeability performance, enhance soil waterholding capacity, accelerate the infiltration capacity of the soil, reducing the woodland soilerosion;(4) Compared with the bare land, the vegetation types in all increased the content of thesoil nutrients, reduced salinity, increasing the microbes quantity in the soil, thereby enhancingthe element cycling in soil;(5) The correlation analysis showed that relationship between soil urease, catalase andinvertase more closely, and are indicators of soil hydrological properties characteristics, soilproperties, soil microbes quantity has good correlation. While the poor correlation betweenthe polyphenol oxidase and the other three enzymes, the correlation with other soil factorswere not obvious;(6) The principal component analysis can convert multiple indicators into a compositeindicator of the relatively small number of unrelated, is a simple and practical statisticalmethods. Using principal component analysis on a variety of soil factor analysis, used toillustrate the effects of various soil factors on soil properties, the results showed that: the soilenzyme activities plays a major role in the evaluation of soil properties, so it can be used asevaluation of the soil properties bad relatively satisfactory indicators, wherein urease andinvertase activity is preferred indicator Select. Membership function analysis shouwed thatthe membeiship of the soil quality of the different vegetation types as follows: mixed forestsof tree (0.801)>pure forests (0.560)> shrubbery(0.323)>gressland(0.182)>bare land(0.0760).Mixed forests of trees is the optimal improvement of saline land of the Yellow River Dalta.Fully visible, in the saline-alkali land of the Yellow River Delta region, afforestation isthe better measures to improve the soil prpperties, and the model mixed forest of trees is thepreferred mode of afforestation, Sophora japonica and Ulmus pumila mixed forest is thepreferred species combinations; urease and invertase activity is a priority indicators selected for evaluation of soil properties. |
