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| Effects of land-use types on soil organic carbon mineralization and greenhouse gas emissions in Loess tableland |
| Received:October 29, 2015 |
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| KeyWord:Loess tableland;land use;carbon mineralization;active carbon;greenhouse gas(GHG) |
| Author Name | Affiliation | E-mail | | WU Jian-li | College of Resources and Environment, Northwest A&F University, Key Laboratory of Plant Nutrition and the Agri-environment in Northwest China, Ministry of Agriculture, Yangling 712100, China | | | LIU Meng-yun | College of Resources and Environment, Northwest A&F University, Key Laboratory of Plant Nutrition and the Agri-environment in Northwest China, Ministry of Agriculture, Yangling 712100, China | lmy471993@163.com | | ZHAO Guo-qing | College of Resources and Environment, Northwest A&F University, Key Laboratory of Plant Nutrition and the Agri-environment in Northwest China, Ministry of Agriculture, Yangling 712100, China | | | YU Ya-nan | College of Resources and Environment, Northwest A&F University, Key Laboratory of Plant Nutrition and the Agri-environment in Northwest China, Ministry of Agriculture, Yangling 712100, China | | | LIU Li-wen | College of Resources and Environment, Northwest A&F University, Key Laboratory of Plant Nutrition and the Agri-environment in Northwest China, Ministry of Agriculture, Yangling 712100, China | | | LIU Huan | College of Resources and Environment, Northwest A&F University, Key Laboratory of Plant Nutrition and the Agri-environment in Northwest China, Ministry of Agriculture, Yangling 712100, China | |
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| Abstract: |
| The present study was to investigate soil organic carbon(SOC) mineralization and greenhouse gas emissions under different land-use types. Five vegetation types, cultivated land, natural grassland, mixed forests, shrub land, shrubbery, and arboreal land, were chosen in Xianyang City in the Loess tableland area. SOC mineralization dynamics were examined by indoor airtight culture method and greenhouse gas emissions were determined by manually-closed static chamber technique. Results showed that soil total organic carbon(TOC) distribution pattern was consistent with that of active carbon component, which decreased in order of grassland > forest land > cultivated land. The SOC mineralization was faster at the early stage while became slower at the later stage. Cumulative SOC mineralization in grassland at the 0~5 cm depth was 1.26~1.34 times greater than that of woodland, and 1.82 times higher than that of cultivated land, whereas at the 5~20 cm soil SOC mineralization showed a decreased tendency compared to the 0~5 cm soil depth. A decrease of 48% was observed in cultivated land. The potential of soil SOC mineralization(Cp) under different land use types was between 0.81 and 2.70 mg·kg-1, with significant difference between different land use types(P<0.05). No differences in SOC decomposition rate constant k were found under different land use types. The ratios of soil carbon mineralization potential Cp to SOC showed that the cultivated land had the highest SOC mineralization but the lowest carbon sequestration, whereas the grassland had the lowest SOC mineralization but and the highest carbon sequestration. The emissions of CO2 and N2O were significantly higher in cultivated land than in other land use types. The CH4 absorption intensity was forest land>natural grassland>cultivated land. In conclusion, returning cultivated land to forestland and grassland could greatly promote organic carbon sequestration in soil and slow down emissions of greenhouse gases from soil into the atmosphere. |
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