计划烧除对云南松林土壤微生物及酶活性的影响

Effects of Prescribed Burning on Soil Microbes and Enzyme Activities in Pinus yunnanensis Forests

计划烧除是森林防火与经营的主要手段之一,探究云南松林计划烧除后土壤微生物与酶活性的变化,可为科学实施计划烧除提供参考。以云南省玉溪市新平县照壁山云南松天然次生林为研究对象,对计划烧除后土壤微生物(真菌、细菌、放线菌)与酶活性(蔗糖酶、纤维素酶、脲酶、蛋白酶、过氧化氢酶、磷酸酶)的变化及相关性进行研究。结果表明,(1)云南松林计划烧除后,表层土壤微生物数量急剧下降,但这种影响随着土壤深度增加越来越小。细菌和放线菌数量在0-10 cm土层、真菌数量在0-20 cm土层未烧除样地显著高于烧除样地;细菌、放线菌在11-60 cm土层、真菌在21-60 cm土层受火烧影响小。(2)计划烧除导致大部分表层土壤酶失活,随土层深度增加受影响程度越来越小。土壤蔗糖酶和纤维素酶活性在0-20 cm土层未烧除样地显著高于计划烧除样地,脲酶、蛋白酶在0-10 cm土层显著高于烧除样地,过氧化氢酶活性在0-60 cm土层显著高于烧除样地;磷酸酶活性与其它酶不同,在0-10 cm土层未烧除样地显著低于计划烧除样地,在10-20 cm土层未烧除除样地显著高于烧除样地,在21-60 cm土层,受计划烧除影响小。(3)土壤微生物与酶活性相关分析结果显示,与未烧除样地比较,计划烧除样地细菌与脲酶、过氧化氢酶、磷酸酶、蛋白酶的相关性变化不明显,而与蔗糖酶、纤维素酶的相关性减弱;真菌与蔗糖酶、过氧化氢酶的相关性变化不明显,而与脲酶、纤维素酶、蛋白酶的相关性减弱,与磷酸酶的相关性增强;放线菌与脲酶、过氧化氢酶的相关性变化不明显,与蔗糖酶、脲酶、过氧化氢酶、纤维素酶、蛋白酶相关性减弱,与磷酸酶的相关性增强。因此,计划烧除使土壤表层微生物与酶活性受到显著影响,土壤酶活性与微生物之间的相关性也发生改变。

Prescribed burning is one of the main strategies in forest management for fire prevention.The aim of the present study was to figure out the changes of soil microbial community and enzyme activities after prescribed burning in Yunnan pine forests,by which,we may get the useful information on forest fire prevention and management.Given that,we compared the soil microbial community(e.g.,fungi,bacterial,actinomycetes)and enzyme(e.g.,saccharase,cellulase,urease,protease,catalase,phosphatase)activities between the before and after prescribed burning.In addition,the correlations were also detected.Our data showed that,(1)The number of microorganisms in the top soil was decreased significantly after prescribed burning,with slight influence on that of deep soils.There were more bacteria and actinomycetes in 0–10 cm and fungi in 0–20 cm in unburned samples than that of burned forest,with no obvious difference for bacteria and actinomycetes in 11–60 cm and fungi in 21–60 cm between unburned and burned samples.(2)The reduced enzyme activities were observed in top soil after the prescribed fire treatment.In brief,the activities of saccharase and cellulase in 0–20 cm,urease and protease in 0–10 cm,and catalase in 0–60 cm in control group were significantly higher.However,phosphatase activity was significantly elevated in 0–10 cm but lowered in 10–20 cm soil in burned forests,with no difference in 21–60 cm soils.And(3)the correlation between the number of bacteria and enzyme activities(i.e.,urease,catalase,phosphatase,and protease)in burned forest had no variation,but the value of correlation between bacteria and saccharase in burned forest,cellulase were decreased.The correlation between fungi and invertase and catalase in burned forest had no significantly variation.However,the correlation of fungi and phosphatase in burned forest increased,while the correlation between fungi and phosphatase were decreased.There were no significant difference of correlation between actinomycetes and urease,and catalase in burned and unburned forest,and the correlation of actinomycetes and phosphatase in burned forest were increased.The correlation between soil actinomycetes and saccharase,cellulase,urease,protease,and catalase in burned forest were decreased compared to control.Therefore,the prescribed burning had a significant effect on soil microorganism and enzyme activity,with the correlation between the number of soil microorganism and enzyme activity being changing.