黄土丘陵沟壑区典型人工林土壤CO_2释放规律及其影响因子

Soil CO_2 emission and the driving factors of typical artificial woodlands in the hilly area of the Loess Plateau

为了解黄土丘陵沟壑区人工林土壤有机碳排放特征,于2007年8月、2007年10月和2008年5月对黄土丘陵沟壑区杏树、沙棘和刺槐3种人工林下土壤CO2释放速率及相关环境因子进行研究,探讨了半干旱地区侵蚀环境下不同植被土壤CO2释放速率的变化规律及影响因子。杏树、沙棘和刺槐3种人工林土壤CO2释放存在差异,日平均释放速率分别为0.83～2.61μmol·m-·2s-1、0.83～3.32μmo·lm-·2s-1和0.80～3.45μmo·lm-·2s-1,刺槐和沙棘人工林土壤CO2释放速率高于杏树林,3种人工林的土壤CO2释放速率日变化及季节性变化表现一致,春季和夏季的土壤CO2释放高于秋季。相关分析表明,土壤温度是影响土壤CO2释放的主要因子,但在干旱的春季和夏季,土壤水分是土壤CO2释放的主要限制因子,同时,土壤理化性质和微生物生物量也对土壤CO2释放有显著影响。

To understand soil CO2 emission variation trend and driving factors of different artificial woodlands under semiarid and erosion environment in the hilly area of the Loess Plateau, soil CO2 emission beneath three typical plantations of Prunus armeniaca, Hippophae reamnoides, and Robinia pseudoacacia were measured on August 2007, October 2007 and May 2008. Meanwhile some environmental factors which related with soil CO2emission were also measured. The results showed that： （1） soil CO2 emission for different artificial woodlands was different and the daily value was 0.83 -2.61gmol .m^-2. s^-1, 0.83 -3.32μmol.m^-2.s^-1, and 0. 80 - 3. 45μmol.m^-2. s^-1 for Prunus armeniaca, Hippophae reamnoides, and Robinia pseudoacacia respectively, the soil CO2 emission of Hippophae reamnoides and Robinia pseudoacacia were higher than that of Prunus armeniaca; （2） different artificial woodlands had similar soil CO2emission diurnal and seasonal variation trend, soil CO2emission was higher in spring and summer; （3） significant correlation between soil CO2 emission and environmental factors was found after regression and correlation analysis, soil temperature was main factor from the whole year but in the spring and summer which were droughty the soil moisture was the main factor, besides, soil physiochemical characters and soil microbial biomass also could influence soil CO2 emission.