目标树经营对兴安落叶松人工林土壤胞外酶的影响

Effects of crop tree management on soil extracellular enzymes in Larix gmelinii plantation

【目的】分析目标树经营6年后土壤养分与土壤胞外酶活性的变化以及二者之间的关系。探讨目标树经营在提高人工林土壤肥力中的作用,为加速形成优质高产的人工林提供理论基础和实践支撑。【方法】以大兴安岭地区松岭林业局绿水林场30年生的兴安落叶松人工林为研究对象,在目标树经营与未经营林分各设置3块30 m×30 m的样方,在每个样方按0~10、10~20、20~40 cm 3个土层分别取样,并测定土壤酶活性和土壤养分含量。【结果】1)在同一土层下,与对照相比,经营组中土壤有机碳的含量在0~10 cm土层中显著增加了18.5%,碳氮比在0~10 cm和10~20 cm两个土层中分别显著增加了40.5%和21.8%,有效磷含量在0~10 cm土层中显著增加了30.1%,微生物量碳含量在0~10 cm和10~20 cm两个土层中分别显著增加了64.2%和37.8%,微生物量氮含量在0~10 cm土层中显著增加了32.3%。而经营组中的全氮含量在0~10 cm土层中显著减少了19.8%。2)经营组中的多酚氧化酶活性在0~10 cm土层中显著提高了16.8%,β葡萄糖苷酶活性在0~10 cm和10~20 cm两个土层中分别显著降低了45.8%和45.1%,木糖苷酶活性在0~10、10~20和20~40 cm 3个土层中分别显著降低了146.8%、220.4%和246.1%。3)冗余分析表明,目标树经营引起的土壤有机碳和全磷含量的变化可能是引起土壤酶活性变化的主要原因。【结论】目标树经营对兴安落叶松人工林的土壤养分和胞外酶活性均有显著的影响,且目标树经营引起土壤养分的变化是影响胞外酶活性变化的主要原因。

【Objective】The changes in soil nutrients and soil extracellular enzyme activity and the relationship between them were analyzed of the crop tree managed after 6 years in 30-year-old Larix gmelinii plantation in Lyushui forest farm of Songling Forestry Bureau in Greater Khingan mountains.Discuss the role of crop tree management in improving the soil fertility of planted forests,and provide theoretical foundation and practical support for accelerating the formation of high-quality and high-yield plantations.【Method】Three 30 m×30 m plots were set in the crop tree stand and unmanaged stand respectively.Soil samples were taken from each plot at the three levels of 0-10 cm,10-20 cm and 20-40 cm respectively to determine the soil enzyme activity and soil nutrient content.【Result】1)Under the same soil layer,compared with the control,the content of soil organic carbon in the management group is significantly increased by 18.5%in the 0-10 cm soil layer,and the carbon to nitrogen ratio is in the two soil layers of 0-10 cm and 10-20 cm.In the 0-10 cm soil layer,the available phosphorus content increase significantly by 30.1%,and the microbial biomass carbon content increase significantly by 64.2%in the 0-10 cm soil layer and 10-20 cm soil layer.And 37.8%,the microbial biomass nitrogen content in the 0-10 cm soil layer significantly increase by 32.3%.The total nitrogen content in the management group is significantly reduced by 19.8%in the 0-10 cm soil layer.2)The polyphenol oxidase activity in the management group significantly increase by 16.8%in the 0-10 cm soil layer,and theβglucosidase activity in the 0-10 cm and 10-20 cm soil layers are significantly reduced by 45.8%and 45.1%,the xylosidase activity is significantly reduced by 146.8%,220.4%and 246.1%in the three soil layers of 0-10 cm,10-20 cm and 20-40 cm,respectively.3)Redundancy analysis showed that changes in soil organic carbon and total phosphorus content cause by crop tree management might be the main reason of changes in soil enzyme activity.【Conclusion】The crop tree management has a significant impact on the soil nutrients and extracellular enzyme activities of the Larix gmelinii plantation,and the changes in soil nutrients caused by the crop tree management are the main reason for the changes in extracellular enzyme activities.