当归种植地土壤微生物数量及土壤酶活性的动态变化研究

The research on the dynamic change of soil microbial quantity and enzyme activity in Angelica sinensis cultivation lands

通过对当归连作种植地和轮作地土壤微生物数量和几种常见土壤酶活性的测定,分析当归种植地土壤微生物数量及土壤酶活性的动态变化特征,探讨当归连作障碍发生的相关因素.用稀释平板计数法测定土壤中微生物数量,用比色法和滴定法测定土壤酶活性.结果显示采样地土壤微生物总数当归-大豆轮作地最多,当归连作地次之,荒地最少;细菌数量和放线菌数量的变化和微生物总数量的变化一致;土壤中真菌数量当归连作地最多,其次为轮作地,荒地最少.土壤过氧化氢酶和脲酶活性呈现降—增—降的变化趋势;中性磷酸酶和纤维素酶活性呈现先增后降的趋势;碱性磷酸酶和多酚氧化酶活性随季节的变化逐渐降低.表明当归连作使土壤中细菌和放线菌数量减少,真菌数量增多;当归不同种植方式会影响土壤酶的活性;土壤中性磷酸酶和纤维素酶活性与土壤中微生物总数和细菌数量变化趋势相一致,而过氧化氢酶的活性则与真菌数量的变化趋势一致.

T his paper aims to uncover the factors w hich led to continuous cropping obstacles in A ngelica sinensis by the dynamical change characters and interrelation between microorganism and enzyme activity in A ngelica sinensis cultivation soil . The numbers of microorganisms in the soil are determined by dilution plate counting , and microbial species are identified by the morphological observation of microscope , physiological and biochemical tests and PDA medium selection . Soil enzyme is determined by corresponding colorimetry and titration . The total number of microorganisms in different sample soils are compared as follows ：rotational cropping soil〉 Angelica sinensis planting land〉 uncultivated land . The variety of bacteria number is consistent with the trend of total number of microorganisms . For the fungi , the number variation is ：A ngelica sinensis planting land 〉 rotational cropping soil 〉 uncultivated land . The Micrococcus , Bacillus and A zotobacter have a large proportion in the soil . The Streptomyces and Nocardia ,having a large proportion ,are found from actinomycete;In fungi , Mucor and Trichod‐erma account for a large proportion .Besides ,the change trend of several enzymes in Angelicasinensis planting lands is as follow s ：catalase and urease activity presented the trend of “dow n‐up‐dow n”;T he trend of＆nbsp;neutral phosphatase and cellulase activity initially increase and subsequently decrease in different seasons , The alkaline phosphatase and polyphenol oxidase activity gradually decrease too . A ngelica sinensis continuous cropping makes the quantity of bacteria and actinomycetes decreased in the soil , but the quantity of fungus is increasing . So the different ways of planting for A ngelica sinensis will effect the activity of soil enzyme . The neutral phosphatase and cellulase activity in the soil are consistent sinensis with the total number of soil microorganisms and change trend of bacteria number . However ,catalase activity in the soil is conformity with the quantity of fungus change .