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CH4是重要的温室气体之一,其主要排放源是森林土壤。本研究采用静态箱法对华南地区尾叶桉林(Eucalyptusurophylla)(B1),厚荚相思林(Acacia crassicarpa)(B2),10个树种的混交林(B3)和30个树种的混交林(B4)4种林型土壤CH4通量进行了原位测定,研究剔除林下灌草和添加翅荚决明(Cassia alata)对土壤CH4通量的影响。4个处理包括:(1)剔除林下灌草并添加翅荚决明(UR+CA);(2)仅剔除林下灌草(UR);(3)仅添加翅荚决明(CA);(4)对照(CK)。研究结果表明:林型变化对土壤CH4通量有重要影响,B1和B2表现为CH4的汇,而B3和B4为CH4的源,剔除林下灌草能改善土壤微生物活性,加快土壤矿化速度,促进CH4的吸收;而林下添加翅荚决明,由于翅荚决明根系的固氮作用,能加快土壤CH4的排放,表层土壤温度和湿度与土壤CH4通量具有强相关性;土壤有机碳(SOC)和可溶性N也是影响CH4通量的重要因子。本研究对探寻人工林管理措施对土壤CH4捧放影响机制具有重要的意义。
CH4 is one of the most important greenhouse gases and its main source of emissions is forest soils. In this study, static box method was used to study the effects of Eucalyptus urophylla (B1), Acacia crassicarpa (B2), mixed forest (B3) of 10 species and mixed forest (B4) The CH4 flux in forest soil was measured in situ to study the effect of removing shrubs and adding Cassia alata on soil CH4 fluxes. The four treatments included: (1) removal of understory shrubs and addition of UR + CA; (2) removal of understory shrubs (UR); (3) ; (4) control (CK). The results showed that forest type change had an important effect on soil CH4 flux, B1 and B2 showed sinks of CH4, and B3 and B4 were sources of CH4. Excluding understorey shrubs could improve soil microbial activity and accelerate soil mineralization rate , And promoted the absorption of CH4. However, the addition of winged Cassia obtusifolia increased the soil CH4 emission due to the nitrogen fixation effect of Cassia obtusilominate roots. The surface soil temperature and humidity had a strong correlation with soil CH4 flux. Soil organic carbon (SOC) and soluble N are also important factors affecting CH4 flux. This study is of great significance to explore the mechanism of plantation management on soil CH4 holding.