西安南郊夏秋季不同土壤碳排放量的变化研究

根据NaOH溶液吸收CO2原理,对西安南郊不同土层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,关中地区夏秋季土壤(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;深层土壤释放量波动小,且释放量小与厚土层;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释放量白昼小于夜间,白天约占1/3,夜间约占2/3;薄土层CO2释放量白昼大于夜间,白天约占2/3,夜间约占1/3。土层CO2观测揭示了CO2释放量与释放规律与土层厚度、深度有关。

Changes of CO2 Release from Soils in Summer and Autumn in Southern Suburb of Xi'an

By means of CO2 absorption by NaOH solution,the CO2 release from different soils was observed in southern suburb of Xi'an.Results showed the release amount of soil layer(thick soil layer) has the negative correlation with temperature,the change of the former is about 4～6 hours later than the temperature change;The CO2 release 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 fluctuation of release amount from deep soil layer is small.And the release amount of the deep soil layer is less than that of the thick soil layer;The change of release amount of CO2 from soil is closely related to temperature and weather,the release amount is large when temperature is high and it's sunny;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 CO2 release from different soils indicated that the release amount and the change law of release are related to thickness and depth of soil layer.