不同熏蒸方式对连作桃园土壤的影响

在位于杭州市余杭区的某连作10年的桃园,使用生物熏蒸和化学熏蒸方式对桃园土壤进行消毒,其中,生物熏蒸分别以茭白秸秆、鸡粪砻糠为材料,化学熏蒸以棉隆为材料,于旺盛生长季,测定处理前后土壤微生物群落、土壤酶活性和土壤基础理化性质的变化,探究不同熏蒸消毒方式对桃园连作土壤的影响。结果表明,化学熏蒸显著(P<0.05)降低了镰孢菌属(Fusarium)等有害菌的相对丰度,并显著(P<0.05)降低了真菌、细菌群落的多样性、丰富度和均匀度;而生物熏蒸则显著(P<0.05)提升了镰孢菌属的相对丰度,并显著(P<0.05)降低了真菌、细菌的多样性和细菌丰富度、真菌均匀度。此外,2种生物熏蒸显著(P<0.05)提高了青霉属(Penicillium)、毛壳菌属(Chaetomium)等有益菌类的相对丰度,而化学熏蒸对沙蜥属(Saitozyma)、毛壳菌属等有益真菌存在显著(P<0.05)抑制作用。生物熏蒸显著(P<0.05)提高了土壤脲酶、蔗糖酶和过氧化氢酶活性,茭白秸秆熏蒸还显著(P<0.05)提高了土壤酸性磷酸酶活性,而鸡粪砻糠熏蒸却显著(P<0.05)降低了土壤酸性磷酸酶活性;化学熏蒸显著(P<0.05)降低了土壤脲酶、过氧化氢酶活性和酸性磷酸酶活性。茭白秸秆熏蒸后,土壤有机质和氮磷钾等养分含量显著(P<0.05)提高,且缓解了土壤酸化;鸡粪砻糠处理后,土壤交换性镁、钙含量显著(P<0.05)升高;棉隆熏蒸后,土壤氮磷钾养分含量显著(P<0.05)下降。综上,适当的生物熏蒸有利于改善土壤微生物群落结构,提高土壤养分;化学熏蒸有利于抑制土壤有害菌生长,但不利于土壤酶活性的发挥,及土壤养分的转化和积累。

Effects of different fumigation on continuous cropping soil in peach orchard

In order to explore the impact of different fumigation on continuous cropping soil in peach orchard, a peach orchard cultivated for 10 a in Yuhang District, Hangzhou City, was selected as test area. The soil in this orchard was disinfected by biological fumigation (with either water bamboo straw or chicken manure) and chemical fumigation (with dazomet). During the vigorous growing season, the changes of soil microbial communities, soil enzyme activities and soil basic physicochemical properties were determined before and after treatment. It was shown that chemical fumigation significantly (P<0.05) reduced the relative abundance of harmful fungi such as Fusarium and significantly (P<0.05) reduced the diversity, richness and uniformity of fungi and bacterial communities. Biological fumigation significantly (P<0.05) increased the relative abundance of Fusarium, and significantly (P<0.05) reduced the diversity of fungi and bacteria, and bacterial richness, and fungal uniformity. In addition, biological fumigation significantly (P<0.05) increased the relative abundance of beneficial funi such as Penicillium and Chaetomium, while chemical fumigation had a significant (P<0.05) inhibition effect on beneficial fung: such as Saitozyma and Chaetomium. Biological fumigation significantly (P<0.05) increased soil urease, sucrase and catalase activities, and fumigation with water bamboo straw also significantly (P<0.05) increased soil acid phosphatase activity, while fumigation with chicken manure significantly (P<0.05) reduced soil acid phosphatase activity. Chemical fumigation significantly (P<0.05) reduced soil urease, catalase activity and acid phosphatase activity. After fumigation with water bamboo straw, the contents of soil organic matter and nitrogen, phosphorus and potassium were significantly (P<0.05) increased, and soil acidification was alleviated. After fumigation with chicken manure, the contents of soil exchangeable magnesium and calcium were increased significantly (P<0.05). However, after chemical fumigation, the contents of soil nitrogen, phosphorus and potassium decreased significantly (P<0.05). In summary, appropriate biological fumigation was conducive to improve the soil microbial communities structure and increase soil nutrients, while chemical fumigation was conducive to inhibite the growth of harmful soil microbes, yet was not conducive to the exertion of soil enzymes activities and the transformation and accumulation of soil nutrients.