西安地区不同厚度土层土壤CO_2释放量的差异研究

A STUDY ON THE DIFFERENCE OF CO_2 RELEASED FROM SOILS WITH DIFFERENT THICKNESS IN XI'AN

根据N aOH溶液吸收CO2的原理,对西安地区夏季不同植被下不同厚度土层土壤CO2释放量进行了观测,并对不同厚度土壤CO2释放规律及其影响因素进行了探讨。资料表明,从当日早晨到次日早晨,夏季不同植被下不同厚度土层土壤CO2释放量均呈现由低到高再到低的变化规律;植被对厚土层土壤CO2释放量有一定影响,植被发育好,土壤CO2释放量大,但是对薄土层影响较小;薄土层土壤CO2释放量变化相对于气温的变化几乎是同步的,而厚土层土壤CO2释放量变化相对于气温的变化具有明显的滞后性,表明土壤CO2释放量变化受土壤温度制约。厚土层CO2释放量均大于薄土层释放量。

On the basis of the principle that CO_2 is absorbed by the solution of NaOH,the CO_2 amount released from soils in different depth under different vegetation is observed in the summer in Xi'an,and the change pattern of CO_2 released from soil and the factors affecting the releasing of CO_2are studied.The results show that the CO_2 amount released from soils at different depth under different vegetation changes from low to high and then to low from the very morning to the next in summer.Vegetation plays a part in affecting the CO_2 amount released from the thick soil.The vegetation develops better and produces more CO_2.But it rarely affects thin soil.Change of the CO_2amount released from thin soil is almost synchronous with the change of temperature,but the time of high amount of CO_2 released from thick soil is lagged behind the change of temperature.The reason why the phenomenon occurs is that the change of soil temperature is later than the change of the air temperature.This shows that the change of the CO_2 amount released from soils is determined by soil temperature.The CO_2 amount released from thick soil is larger than that from thin soil.