【作者】 郝建茹；

【导师】 张彦东；

【作者基本信息】 东北林业大学 ， 森林培育， 2010， 硕士

【摘要】 为了解采伐及伐后土地利用方式改变对东北温带次生林土壤微生物生物量碳氮的影响,在东北林业大学帽儿山实验林场,选择典型次生杂木林进行了四种采伐处理(皆伐后造林、皆伐后农作、50%强度采伐和25%强度采伐),连续两年测定土壤微生物生物量碳氮的变化结果表明：不同采伐处理次生林各层土壤(0～10 cm和10～20 cm)微生物生物量碳均表现为：皆伐后造林>50%强度采伐>皆伐后农作>25%强度采伐≌对照,但各处理间差异不显著(P>0.05)。土壤微生物生物量氮表现为：皆伐后造林>皆伐后农作>50%强度采伐>25%强度采伐≌对照,但各处理间差异也不显著(P>0.05)。不同采伐处理土壤微生物生物量碳氮0～10 cm土层含量显著高于10～20 cm土层(P<0.05)；土壤微生物生物量碳在0～10 cm土层变幅为208.36～2284.51 mg·kg-1,10～20 cm土层变幅为75.79～980.72 mg·kg-1。土壤微生物生物量氮在0～10 cm土层变幅为66.97～325.34 mg·kg-1,10～20 cm土层变幅为16.11～126.59 mg.kg-1。不同采伐处理土壤微生物生物量碳氮均具有明显的季节变化,表现出春秋两季高,夏季低。不同采伐处理土壤微生物熵在生长季平均值为：对照>25%强度采伐>皆伐后造林>皆伐后农作>50%强度采伐,但各处理样地差异不显著(P>0.05)。不同采伐处理各样地土壤微生物熵0～10 cm土层和10～20 cm土层差异不显著(P>0.05)。不同采伐处理土壤微生物熵变幅度为1.12～4.47,林地经过采伐后,有大量的采伐剩余物,短期内土壤有机碳和微生物碳增加,但是微生物熵下降,这表明采伐导致土壤质量下降。不同采伐处理土壤有机碳、全氮、硝态氮、铵态氮、全磷、速效磷、全钾、均表现出春秋高夏季低的变化规律。不同采伐处理土壤有机碳、全氮、硝态氮、铵态氮、全磷、速效磷、全钾、土壤温度、土壤湿度、pH值0～10 cm土层含量均显著高于10～20cm土层(P<0.05)。土壤有机碳和全氮与土壤微生物生物量碳氮呈极显著相关(P<0.01),说明土壤微生物量碳氮可作为衡量土壤有机碳和养分变化的敏感指标。土壤微生物量碳氮与土壤湿度和全磷之间呈极显著相关(P<0.01),表明土壤湿度和全磷是影响土壤微生物生物量变化的主要因子。土壤微生物生物量碳氮与矿化氮呈显著相关(P<0.05)。土壤微生物量碳氮与土壤有效磷、全钾、湿度和pH值之间不相关(P>0.05)。本研究表明,在采伐处理一个生长季后,土壤微生物生物量碳氮具有明显的季节变化。土壤有机质和全氮是影响微生物生物量变化的主要因子。东北温带次生林皆伐后农作、皆伐后造林和较大强度的择伐短期内土壤微生物量增加,但土壤质量下降。更多还原

【Abstract】 Reponses of soil microbial biomass carbon and nitrogen to different harvest methods and land use patterns after cutting were measured in Maoershan Experimental Forest Farm of Northeast Forestry University. Second shaw growth was chosen to be processed in four treatments (afforestation (forestation after clear cutting), cropland (farming after clear cutting), partial cutⅠ(50% of the stand volume removed), partial cutⅡ(25% of the stand volume removed)). In two consecutive years, dynamic of soil microbial biomass carbon and nitrogen were measured. The results showed:The soil microbial biomass carbon (SMBC) from different treatments range as follow: afforestation, partial cutⅠ, cropland, partial cutⅡ, control(uncut). And the soil microbial biomass nitrogen (SMBN) range as follow:afforestation, cropland, partial cutⅠ, partial cutⅡ, control. The amounts of soil microbial biomass carbon and nitrogen in the 0-10 cm horizon from different treatments is significantly higher than that in 10-20 cm soil horizon; SMBC contents in 0-10cm and 10-20cm soil horizons varied respectively from 208.36 to 2284.51mg.kg-1 and from 75.79 to 980.72mg.kg-1. SMBN contents in 0-10cm and 10-20cm soil horizons ranged from 66.97 to 325.34mg.kg-1 and from 16.11 to 126.59mg.kg-1 respectively. The contents of SMBC and SMBN showed obvious seasonal variation, high in spring and autumn, and low in summer.The soil microbial quotient from different treatments range as follow:control, partial cutⅡ, afforestation, cropland, partial cutⅠ. There are no significant differences among different harvest methods. The microbial quotient varied from 1.12 to 4.47. There are also no significant differences between 0-10cm soil horizon and 10-20cm soil horizon. After woods harvested, there are a large number of logging slash in the forest land, so that soil organic carbon(SOC) and SMBC increased rapidly. But soil microbial quotient decreased, and soil degrade.SOC, total nitrogen, nitrate, ammonium, total phosphorus, available phosphorus, total potassium, pH, soil temperature and moisture in the 0-10cm soil horizons were higher significantly than that in the 10-20cm soil horizons. SOC, total nitrogen, nitrate, ammonium, total phosphorus, available phosphorus and total potassium showed significant seasonal dynamics, high in spring and autumn, and low in summer.Soil organic carbon and total nitrogen correlated significantly with SMBC and SMBN. It shows SMBC and SMBN are sensitive indicators of soil organic carbon and nutrient. Soil moisture and total phosphorus can affect significantly SMBC and SMBN. But available phosphorus, total potassium, soil moisture and pH have no correlations with SMBC and SMBN.After harvesting, SMBC and SMBN showed obvious seasonal variation. SOC, total nitrogen, total phosphorus and soil moisture had important effects on SMBC and SMBN. Soil microbial biomass in the plots of afforestation,cropland and partial cut I increased in short-term, but the quality of soil decreased.更多还原