Seasonal variation of soil respiration and its components in tropical rain forest and rubber plantation in Xishuangbanna,Yunnan
西双版纳热带季节雨林与橡胶林土壤呼吸的季节变化

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.