水热因素对城乡梯度森林土壤碳矿化的影响  

Effects of temperature and humidity conditions on the forest soil C mineralization along an urban-rural gradient

作　　者：卢锐[1] 彭小英[1] 刘以珍[2] 余明泉[1] 

机构地区：[1]江西科技师范大学生命科学学院,江西南昌330031 [2]南昌大学生命科学学院,江西南昌330031

出　　处：《南昌大学学报（理科版）》2015年第2期199-204,共6页Journal of Nanchang University(Natural Science)

基　　金：江西省自然科学基金资助项目(2010GZN0024);江西省教育厅科学技术基金资助项目(GJJ11594)

摘　　要：城市化过程和水热因素可以影响土壤微生物活性,进而影响土壤碳平衡,然而很少有研究在城乡梯度上探讨水热因素对土壤有机碳矿化的影响。本文以南昌城市-郊区-农村草地土壤为研究对象,在不同温度（15,25,35℃）和水分含量（20%,30%,40%）条件下利用静态碱液吸收法测定土壤有机碳矿化动态。结果表明：各条件下,土壤培养45d后累积碳矿化量在1.25~7.69gC·kg-1范围内。在同一地区,温度可以显著促进土壤碳矿化,而水分对土壤碳矿化量的影响仅在培养后期才表现出来;在相同水热条件下,城区与农村土壤碳矿化量差异显著,郊区与城区及郊区与农村之间的差异在培养后期才逐渐显著。经45d室内培养后,同等水热条件下,城区土壤累积碳矿化量是农村的1.53~2.00倍,这一比值随着温度升高而减小,随水分含量的升高而增加。土壤碳矿化量总体表现为沿城乡梯度递减,表明城市化过程将提高土壤碳矿化速率,降低有机碳的稳定性。建议决策者采取措施降低城市森林土壤碳矿化量,减少土壤中CO2的释放,以应对全球气候变化。The process of urbanization, temperature and humidity conditions could affect the soil microbial activity, which thereby might alter the soil carbon balance ultimately. However litter studies have assessed the effects of temperature and humidity conditions on soil carbon mineralization along an urban-to-rural gradient. In this study,some sample soils along an urban-to-rural gradient in Nanchang were incubated at various temperatures （ 15,25,35 ℃ ） and humidity conditions （20%, 30 %, 40 % ）. The results showed that after 45 d incubating soil carbon cumulative mineralization at various conditions ranged from 1.25 to 7.69 gC/kg. Mineralization of soil organic carbon （SOC） was strongly positively correlated with temperature through 45 d incubating（P〈0. 001） ,while the effect of humidity condition on mineralization was only remarkable at later stage of incubation. At the same hydrothermal conditions, soil carbon mineralization in urban area was significant different from that in rural area. However, there was no significant difference between the soil in urban and suburban area or rural and suburban area until the later stage of incubation. At the end of 45 d incubating,soil carbon cumulative mineralization in urban area was 1.53-2.00 times than that in rural area at the same hydrothermal conditions. This rate had a positive correlation with humidity condition while had a negative correlation with temperature. Consequently, soil carbon mineralization decreased along an urban-to-rural gradient, which indicated that the process of urbanization would lead to the enhancement of soil carbon mineralization rate as well as the decrease of stability of soil organic carbon. Thus, in order to response to global climate change, decision-makers should take measures to reduce soil carbon mineralization and decrease the release of CO2 from soil.

关 键 词：碳矿化 温度 水分 城乡梯度 

分 类 号：X651[环境科学与工程]