| The soil salinization has become a worldwide environmental problem. There is more than 25% of land belong to saline soil worldwide,and more than 80% saline soil has not been harnessed in China. Therefore, reasonable exploitation and utilization this kind land resources has a great potential and economic value. In addition, revealing the mechanism of salt tolerance plants and biological remediation process of soil salinization is significant for promoting the sustainable use of soil salinization. This paper took soil salinization area of Qinhuangdao in Hebei province as the study object and set 10 kinds of typical salt tolerant plants(Tamarix chinensis Lour., Nitraria sibirica Pall, Elaeagnus angustifolia Linn., Robinia pseudoacacia Linn., Ulmus pumila L., Suaeda salsa(Linn.) Pall., Salicornia europaea, Aeluropus littoralis(Willd.) Parl., Artemisia halodendron Turcz. ex Bess., Achnatherum splendens) that were planted more than 5 years to analyze the influence of those 10 salt-tolerant plants on soil physicochemical properties, nutrient contents, the quantity of microorganism and enzyme activity. The results were as follows:1. The changes of soil physical and chemical properties. After 5 years of growing salt tolerant plants, soil mechanical composition improved and soil water content increased. Soil bulk density, p H value and salinity decreased significantly. Compared with control group, Artemisia halodendron decreased the soil bulk density best by 52.77% within 0~30 cm soil layer. Tamarix chinensis decreased soil p H and salinity best by 24.71% and 24.71% respectively. A. halodendron, Suaeda salsaand Ulmus pumila had the strongest ability to improve the salinization of soil mechanical composition and A. halodendron improved the salinization of soil moisture best with 50.27%. Especially in the surface soil within 0~10 cm, salt tolerant plants can significantly improve soil physical and chemical properties.2. The changes of nutrients in salinization soil. After 5 years of growing salt tolerant plants, organic matter, total nitrogen content, available phosphorus and available potassium content in salinization soil were increased. Compared with control group, Nitraria sibirica improved the content of organic matter in salinization soil best with 333.33% within 0~30 cm soil layer. Robinia pseudoacacia increased the total content of soil nitrogen, available phosphorus and available potassium in salinization soil and increased by 315.70%, 225.00% and 315.70%respectively. Especially in the surface soil within 0~10 cm, salt tolerant plants can significantly improve soil nutrients.3. The changes of the activity of enzyme in salinization soil. After 5 years of growing salt tolerant plants, the activity of cellulase, urease and dehydrogenase in salinization soil were increased.Compared with control group, S. salsa with the strongest ability improved the activity of urease and the value was 3.51×10-2 mg glucose per gram soil that was the 1.47 times as much as the control group within 0~30 cm soil layer.Aeluropus sinensis was the salt tolerant plants that was with the maximum soil urease activity and the value reached 10.91 mg urea /(kgsoil/h) that was 4.12 times as much as the control group. Salicornia europaea improved the dehydrogenase activity of salinization soil best, and the value was 1.23 mg TPF/(kgsoil/h). Especially in the surface soil within 0~10 cm, salt tolerant plants can significantly improve the activity of enzyme in salinization soil.4. The change of microbial quantity in salinization soil. After 5 years of growing salt tolerant plants, the number of soil bacteria, fungi and actinomycetes were significantly increased in salinization soil. Compared with control group, A. halodendron increased the number of soil bacteria best and the amount reached 17.75×106 per pram dry soilthat was the 4.49 times as much as the control group. T. chinensis increased the number of soil fungi best and the amount reached 74.84×103 per pram dry soilthat was the 20.20 times as much as the control group. T. chinensis increased the number of soil actinomycetes best and the amount reached 34.84×104 per pram dry soilthat was the 2.58 times as much as the control group. Especially in the surface soil within 0~10 cm, salt tolerant plants can significantly improve the change of microbial quantity in salinization soil. |
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