摘要
采用野外采样和室内培养试验,研究了不同土地利用类型(林地和旱地)下的石灰土表层土壤有机碳(SOC)矿化对变温环境的响应.两种供试土样分别采自贵州省普定县天龙山区域的典型林地和旱地的0~10 cm表层.在培养试验中,依据积温相同的原则,设置变温(范围:15~25℃,变温间隔12 h)和恒温(20℃)两个温度处理,培养时间为56 d.在整个培养期内,旱地石灰土变温处理的SOC累积矿化量(63.32 mg·kg-1)虽略低于恒温处理(63.96 mg·kg-1),但两者之间差异不显著,而森林石灰土变温处理的SOC累积矿化量(169.46 mg·kg-1)则显著低于恒温处理(209.52 mg·kg-1)(P<0.05),这表明不同土地利用类型的石灰土SOC矿化对变温环境的响应不同.受植被和土地利用类型的影响,森林石灰土和旱地石灰土表层的SOC含量和组成差异显著,这可能是导致其SOC矿化对变温环境响应差异的重要原因.另外,各温度处理中,土壤可溶性有机碳(DOC)含量与SOC日均矿化量之间均呈极显著正相关(P<0.01),表明制约土壤DOC生成是温度影响土壤有机碳矿化的一个重要途径.在培养过程中,土壤微生物量碳含量不能有效反映恒温和变温下的SOC矿化差异,结合矿化动力学分析可知,同恒温相比,变温虽然不能通过改变微生物数量来影响SOC矿化,但能通过改变微生物群落的总体活性来影响SOC矿化过程.
Soil sampling in the field and incubation experiment in the laboratory were conducted to investigate the responses of soil organic carbon (SOC) mineralization to variable temperature regimes in the topsoil of limestone soils from forest land and dry land. Two incubated limestone soils were sampled from the 0-10 cm layers of typical forest land and dry land respectively, which were distributed in Tianlong Mountain area of Puding county, Guizhou province. The soils were incubated for 56 d under two different temperature regimes including variable temperature ( range: 15- 25℃, interval: 12 h) and constant temperature (20℃), and the cumulative temperature was the same in the two temperature treatments. In the entire incubation period (56 d), the SOC cumulative mineralization (63. 32 mg·kg - 1 ) in the limestone soil from dry land (SH) under the variable temperature was lower than that (63. 96 mg·kg - 1 ) at constant 20℃, and there was no significant difference in the SOC cumulative mineralization between the variable and constant temperature treatments (P 《 0. 05). While the cumulative mineralization (169. 46 mg·kg - 1 ) of organic carbon in the limestone soil from forest land (SL) under the variable temperature was significantly lower than that (209. 52 mg·kg - 1 ) at constant 20℃. The results indicated that the responses of SOC mineralization to the variable temperature were obviously different between SL and SH soils. The SOC content and composition were significantly different between SL and SH soils affected by vegetation and land use type, which suggested that SOC content and composition were important factors causing the different responses of SOC mineralization to variable temperature between SL and SH soils. In addition, the dissolved organic carbon (DOC) content of two limestone soils were highly (P《 0. 01) positively correlated with daily mineralization of soil organic carbon in both temperature treatments, which implied that controlling DOC production was an important way for the temperatu
出处
《环境科学》
EI
CAS
CSCD
北大核心
2014年第11期4291-4297,共7页
Environmental Science
基金
国家自然科学基金项目(41301245)
中国科学院战略性先导科技专项(XDA05050506)
中央高校基本科研业务费专项(XDJK2013B043)
重庆市环境保护局环保科技项目(环科字2010第26号)
关键词
土壤有机碳
矿化
温度
土地利用
可溶性有机碳
soil organic carbon
mineralization
temperature
land use
dissolved organic carbon
