西双版纳热带季节雨林与橡胶林土壤呼吸的季节变化

采用挖壕沟法与红外气体分析法,研究了西双版纳热带季节雨林和人工橡胶林内土壤呼吸包括根系呼吸、异养呼吸的干湿季动态变化.结果表明：季节雨林内土壤呼吸和异养呼吸速率均显著大于橡胶林(P＜0.01)，但根系呼吸差异不显著；土壤温湿度是呼吸速率变化的主要影响因子，季节雨林和橡胶林内土壤呼吸和异养呼吸速率均为雨季＞干热季＞雾凉季，但季节雨林内根系呼吸为雨季＞雾凉季＞干热季，而橡胶林内为雾凉季＞雨季＞干热季；季节雨林内根系呼吸对土壤呼吸的贡献率(29%)小于橡胶林(42%，P＜0.01)，而季节雨林内异养呼吸对土壤呼吸的贡献率为71%、橡胶林为58%；当5 cm土壤温度在12 ℃～32 ℃范围内变化时，季节雨林内土壤呼吸及根系呼吸、异养呼吸的Q₁₀值均大于橡胶林，且异养呼吸的Q₁₀值最大而根系呼吸的Q₁₀值最小.

Seasonal variation of soil respiration and its components in tropical rain forest and rubber plantation in Xishuangbanna,Yunnan

By using trenching method and infrared gas analyzer,this paper studied the seasonal variation of soil respiration(SR),including root respiration(RR)and heterotrophic respiration (HR),in tropical seasonal rain forest(RF)and rubber(Hevea brasiliensis)plantation(RP)in Xishuangbanna of Yunnan,China.The results showed that the SR and HR rates were significantly higher in RF than in RP(P＜0.01),while the RR rate had less difference between the two forests.Soil temperature and moisture were the key factors affecting the SR,RR and HR.The SR and HR rates in the two forests were rainy season＞dry-hot season＞foggy season,but the RR rate was rainv season＞foggy season＞dry-hot season in RF,and foggy season＞rainy season＞dry-hot season in RP.The contribution of RR to SR in RF(29%)was much lower than that in RP(42%,P＜0.01).while the contribution of HR to SR was 71%in RF and 58%in RP.When the soil temperature at 5 cm depth varied from 12℃to 32 ℃,the Q_(10) values for SR,HR,and RR rates were higher in RF than in RP.HR had the highest Q_(10) value,while RR had the lowest one.