西安南郊和蓝田夏季土壤CO_2排放量的变化研究

Change law of release amount of CO_2 from soils in summer in southern suburb of Xi′an and Lantian

根据NaOH溶液吸收CO2原理,对西安南郊和蓝田不同成因土层CO2释放量进行了观测,探讨了土壤CO2释放量的变化规律及其影响因素.资料表明,关中地区夏季土壤(厚土层)CO2释放量变化规律与气温变化规律负相关,CO2释放量存在一定的"滞后性",一般滞后4～6h;而薄土层土壤CO2释放量变化规律与气温变化规律正相关,CO2释放量不存在"滞后性",且释放量明显小于厚土层;土壤CO2释放量的变化与温度和天气密切相关,温度高、天气晴朗时释放量大,反之则小;厚土层CO2释放量白天小于夜间,白天约占1/3,夜间约占2/3;薄土层CO2释放量白天大于夜间,白天约占2/3,夜间约占1/3.薄层土CO2观测揭示了CO2释放量和变化规律都与土层厚度有关.

By means of CO2 absorption by NaOH solution, the release amount of CO2 from different soils was observed round the clock in southern suburb of Xi′an and Lantian. Results show that the change law of release. The release amount of soil (thick soil layer) has the negative correlation with temperature, the change of the former is about 4～6 h later than that of the latter. The change law of release amount of CO2 from thin soil layer has the positive correlation with temperature. The release amount of the thin soil layer is less than that of the thick soil layer. The change of release amount of CO2 from soil is closely related to temperature and weather, the release amount is large when temperature is high and it′s sunny. It is small on the contrary. The release amount of thick soil layer is smaller in daytime than at night, account for 1/3 in daytime, account for 2/3 at night; The release amount of thin soil layer is larger at night than in daytime, account for 2/3 in daytime, account for 1/3 at night. The observation of the release amount of thin soil layer not only indicates that the release amount of soil is related to thickness of soil layer, but also indicates that the change law of release amount of CO2 is related to thickness of soil layer.