农田土壤温室气体释放通量的研究

采用碱石灰吸收法和Hohenheim Chamber法测定了德国南部农田CO2释放规律，并对两种方法进行了比较。供试作物为冬小麦。在实验期间内，各处理的CO2净释放量均为正值，表明在春季土壤－作物系统是碳的源。一天内作物－土壤系统在大部分内表现为CO2净释放，只在中午11：00至13：00且光照充分时才出现净同化。不同轮作方式下农田CO2累计释放量存在差异。不同处理CO2累计释放产为净释放，但处理间存在显著差别。CO2净释放量与气温、土壤温度极显著相关，与PAR相关性不明显。研究结果还表明，碱石灰吸收法吸收时间和吸收剂的数量对试验结果有影响，而吸收时间的影响更为明显。

Measurement of Greenhouse Gases Emission Efflux in Farmland

Soil CO\-2 efflux was surveyed by two different methods:soda lime absorption and Hohenheim Chamber(HC), from Jan to Apr, southern Germany. Experiment crop is winter wheat with 4 treatments WRT, LCT, LRT, WCT. Results show that in all treatments, CO\-2 efflux is positive demonstrating in the experinmental period, soil plant system is a net source of C. During 1 day, there are net CO\-2 emission from soil to air in most of the time, except when in 11:00 to 13:00, there are net absorption of CO\-2 in the soil plant system. The net quantity of CO\-2 emission in all treatments is positive with dramatic difference among different treatments. LCT reached the highest point and WCT ranked the lowest. For the reason that the quantity of soil respiration has no significantly difference among treatments (soda lime method revealed), the difference due to plant's photosynthesis. CO\-2 net emission is significantly correlated with air temperature, soil temperature but has no correlationship with PAR. The study also found that the duration of absorption and the amount of soda lime affect the accuracy of the measurement and time duration's effect is bigger than the amount of soda lime.