实验室不同温度下添加细根(草根)对土壤活性有机碳的影响

Effect of Fine Root (Grass Root) Added to Soil on Soil Active Qrganic Carbon Under Different Temperature Condition in the Laboratory Microcosm

研究不同温度(10,20和30℃)条件下分别向土壤中添加光皮桦细根(直径<2 mm)与扁穗牛鞭草草根混合物(处理1)、光皮桦细根(处理2)、扁穗牛鞭草草根(处理3)和柳杉细根(处理4)这4种处理对土壤活性有机碳的影响。结果表明:添加细根的种类、培养温度和培养时间均对土壤微生物量碳、水溶性有机碳、易氧化有机碳和总有机碳含量产生影响;120天后各处理的土壤微生物量碳、水溶性有机碳、易氧化有机碳和总有机碳含量都显著大于对照(P<0.05);在60和120天后,处理1的土壤微生物量碳、水溶性有机碳、易氧化有机碳和总有机碳含量都显著大于其他处理(P<0.05);温度对土壤微生物量碳和水溶性有机碳含量的影响表现为30℃>20℃>10℃,对易氧化有机碳和总有机碳含量的影响表现为10℃>20℃>30℃(P<0.05)。

In this study,the effects of fine root （grass root） decomposition to the soil active organic carbon were investigated in a laboratory microcosm under 10,20 and 30 ℃.The roots were mixed with the soil in the following four treatments： mixture of birch （Betula luminifera） roots and grass （Hemarthria compressa） roots （treatment 1）,birch （Betula luminifera） roots （treatment 2）,grass （Hemarthria compressa） roots （treatment 3）,cedar （Crytomeria fortunei） roots （treatment 4） and no roots （CK）.The results showed that fine root source,incubation time and incubation temperature all influenced soil microbial biomass carbon （SMBC）,water soluble organic carbon （WSOC）,readily oxidized carbon （ROC）,total organic carbon （TOC）.After 120 d,the contents of SMBC,WSOC,ROC,and TOC in the treatments were higher than those in CK （P0.05）.The contents of SMBC,WSOC,ROC,and TOC in treatment 1 were higher than those in the other treatments in 60 or 120 d.The effect of incubation temperature on MBC and WSOC in four treatments was ranked in an order as the following,30 ℃20 ℃10 ℃,while the effect on ROC and TOC was in an order of 10 ℃20 ℃30 ℃（P0.05）.