间伐对杨树人工林土壤微生物量和氮含量的影响

发布时间：2018-07-23 16:11

【摘要】：针对生产中杨树大径材培育存在的问题,设计了4种间伐处理(对照、30%下层伐、50%下层伐和50%机械伐),研究了不同间伐处理对杨树人工林土壤微生物量碳、微生物量氮、土壤无机氮和土壤溶解性有机氮含量的影响及其时间和空间格局。结果表明,由于间伐处理改变了林地土壤的温度和水分条件,导致在生长季高强度间伐处理(50%下层伐和50%机械伐)显著提高了土壤微生物量碳和微生物量氮含量,表现为50%机械伐50%下层伐30%下层伐不间伐,而在非生长季则表现相反的趋势。高强度间伐显著提高了土壤无机氮含量,但50%下层伐和50%机械伐的土壤无机氮含量差异不显著;土壤无机氮(NH_4~+-N和NO_3~--N)主要以硝态氮的形式存在,并表现出明显的季节动态。高强度间伐提高了土壤溶解性有机氮含量,特别在夏季和秋季这种差异达到显著水平。从不同土壤层次看,土壤微生物量、土壤无机氮和溶解性有机氮均表现出明显的表聚性。研究结果可为杨树人工林的可持续经营提供理论依据和技术支撑。
[Abstract]:In view of the problems existing in the cultivation of large diameter timber of poplar, four kinds of thinning treatments (50% and 50% mechanical cutting of poplar plantations) were designed, and the effects of different thinning treatments on soil microbial biomass carbon and microbial biomass nitrogen in poplar plantations were studied. Effects of Inorganic nitrogen and dissolved Organic nitrogen in soil and their temporal and Spatial patterns. The results showed that the soil microbial biomass carbon and microbial biomass nitrogen content were significantly increased during the growing season due to the change of soil temperature and moisture condition by thinning treatment, which resulted in high intensity thinning treatment (50% lower cutting and 50% mechanical cutting) in growing season. The results showed that 50% mechanical felling and 30% undercutting were not thinning, but the trend was opposite in non-growth season. High intensity thinning significantly increased soil inorganic nitrogen content, but there was no significant difference in inorganic nitrogen content between 50% lower cutting and 50% mechanical cutting, and soil inorganic nitrogen (NH4- N and NO_3~--N) mainly existed in the form of nitrate nitrogen, and showed obvious seasonal dynamics. High intensity thinning increased the content of dissolved organic nitrogen, especially in summer and autumn. From different soil levels, soil microbial biomass, soil inorganic nitrogen and dissolved organic nitrogen showed apparent aggregation. The results can provide theoretical basis and technical support for the sustainable management of poplar plantation.
【作者单位】：南京林业大学林学院;南京林业大学南方现代林业协同创新中心;
【基金】：国家科技支撑计划“阔叶树速生丰产林定向培育技术研究”(2015BAD09B02) 国家重点基础研究发展计划(2012CB419600)
【分类号】：S714

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