林木枝条不同处理方式对宁夏沙化草地土壤微生物特性及理化性质的短期影响

Short Term Effect of Different Restoration Strategies Used Tree Branches on Microbial and Physicochemical Properties of Desertified Grassland Soil in Ningxia,China

以不同林木枝条为试材,研究了土壤20cm深度添加长2cm的杨树枝条粉碎材料(A)、土壤添加杨树枝条粉碎材料的基础上同时土表覆盖40cm厚的去除叶片的柳树枝条(AB)、土壤表层覆盖3cm厚的长4cm的混合枝条粉碎材料(M)和不做任何处理的对照(CK),对宁夏沙化草地土壤微生物学特性和土壤理化性质的短期影响。结果表明:林木枝条不同处理方式较CK均不同程度的提高了土壤微生物(细菌、放线菌和真菌)的数量、土壤微生物碳、氮含量和土壤酶(过氧化氢酶、脲酶)活性,增加了土壤中有机碳氮含量、水分含量和土壤水稳性团聚体的比例,同时降低了土壤pH值;总体而言,林木枝条处理对提高土壤微生物活性和改善土壤理化性质的效果依次为AB>A>M>CK;表征土壤微生物特性指标和土壤理化性质的指标间存在显著(P<0.05)或者极显著相关(P<0.01)的关系,同时还符合线性关系(P<0.05);利用林木枝条不同处理方式均为微生物提供了有机能源,改善了土壤环境,促进了微生物对林木枝条的分解和转化,提高了土壤养分含量,同时改善了土壤的结构,可以作为未来沙化草地改良的一种措施。

Taking different tree branches as materials,short term effect of different restoration strategies,20 cm depth soil added 2 cm length poplar branches chips without leaves （A）,added poplar chips plus 40 cm depth willow branches blanket without leaves covered on soil surface （AB）,3 cm depth mixed chips mulched on soil surface （M） and control （CK） ,on microbial and physicochemical properties of decertifies grassland in Ningxia were studied. The results showed that all of three restoration strategies used tree branches increased microbial population, microbial carbon, microbial nitrogen and enzyme activity in soil, and also increased organic carbon, total nitrogen, soil water and water stable aggregate, and decreased pH value in soil. In a word, the effect between strategies were AB〉A〉M〉CK. Furthermore, there were significant （P〈0. 05） or extreme significant （P〈0. 01） correlation between soil microbial properties and soil physicochemical properties,and they were linear correlation （P〈0. 05） at same time. It＇s concluded that, firstly, tree branches supplied energy for microbes and improved environment condition for microbes; then tree branches decomposition and transformation were promoted, nutrients content in soil increased, and soil structure also be improved. So, these strategies could be considered in grassland restoration in future.