黄土区刺槐林土壤含水量变化对土壤呼吸强度的影响  

Effect of Different Soil Water Contents on Soil Respiratory Intensity of Robinia Pseudoacacia Forest in Loess Area

作　　者：吕海波[1,2] 梁宗锁[1,3] 

机构地区：[1]中国科学院水利部水土保持研究所,陕西杨凌712100 [2]渭南师范学院化学与生命科学学院,陕西渭南714000 [3]西北农林科技大学生命学院,陕西杨凌712100

出　　处：《水土保持通报》2013年第1期44-48,52,共6页Bulletin of Soil and Water Conservation

基　　金：中国科学院知识创新项目"土壤-植被-大气界面碳传输的各环节的物理特征和生理生态过程与C库的源汇效应研究"(KZCX2-XB2-05-01);陕西省教育厅项目"大荔沙苑温室西瓜滴灌可行性及最优灌溉制度研究"(12JK0814);渭南市科技创新项目"渭南地区主要农作物秸秆搭配还田的增肥效果研究"(2012JCYJ-7)

摘　　要：通过室内培养实验来评估土壤含水量的变化对土壤枯落物层、不同深度土壤层及DOC淋失后的土壤呼吸的影响。采集安塞纸坊沟31a刺槐林土样及林下混合枯落物,通过碱液吸收法测定100%,20%和2%含水量条件下3个深度土样(20,40和60cm);去除DOC土样(仅100%含水量条件下);3种处理枯落物混合土样(林下混合枯落物、刺槐枯落物和草本类枯落物)培养过程中CO2的累计释放量。结果表明,100%和20%含水量条件下各深度土壤CO2释放量为20cm土样>60cm土样>40cm土样;20cm土样去除DOC后CO2释放量明显减少,40cm明显增加,60cm没有明显变化;混合枯落物土样在100%含水量条件下CO2释放量最高;20%和2%含水量条件下刺槐枯落物CO2释放量明显大于草类,而100%含水量条件下草类枯落物略大于刺槐枯落物。研究证明土壤含水量对SOC组分含量和枯落物种类不同的土壤层呼吸强度存在差异性影响,强降水对DOC的淋失可造成表层土壤呼吸的减弱。An incubational experiment was designed to assess how soil water content affects the respiratory intensities of litter layers, different soil layers and were taken in 31 year Robinia pseudoacacia forest DOC-removed soil samples. Soil and mixed litter samp in Zhifanggou Watershed, Ansai County. The accumu es a- tive CO2 release amounts of soil samples and DOC-removed soil samples（100% water content only） at three soil depths（20, 40 and 60 cm） and in three controlled litter-mixed soil samples（mixed by complex litters, in eluding Robinia pseudoacacia litters and herbage litters） were determined in laboratory under the three soil water contents of 100%, 20% and 2%, respectively. Results showed that the CO2-release levels at the dif ferent soil depths were in the order of： 20 cm 〉 60 cm 〉 40 cm under the controlled 100% and 20% water contents. Under the 100% water content and after DOC was removed, the accumulative COe-release amount of the soil samples at the 20 cm depth decreased, but obviously increased for samples at the 40 cm soil depth and had no remarkable change at the 60 cm soil depth. The accumulative CO2-release amount of complex lit- ter-mixed soil samples was the highest under the 100% water content. The amount of simply Robinia pseud oacacia litter-mixed samples was obviously higher than that of herbage litter mixed samples under the 20 % and 2% water contents, but slightly lower under the 100% water content. The asynchronous effect of watercontent levels is suggested on the respiratory intensity of the soil layers with different SOC compositions and Jitter types. Removed DOC by heavy precipitation from soil subsurface layers can reduce respiratory intensity of surface soil layers.

关 键 词：CO2释放量 土壤呼吸 溶解性有机碳 土壤深度 

分 类 号：S153.6[农业科学—土壤学]