GEOGRAPHICAL RESEARCH ›› 2006, Vol. 25 ›› Issue (2): 335-341.doi: 10.11821/yj2006020018

• Earth Surface Processes • Previous Articles     Next Articles

Effects of land-use on methane oxidation potential in lessive

WANG Chang-ke1,2, Xian-guo2, CAI Zu-cong3, LUO Yong1   

  1. 1. National Climate Center,CMA,Beijing 100081,China;
    2. Northeast Institute of Geography and Agricultural Ecology,CAS,Changchun 130012,China;
    3. Institute of Soil Science,CAS,Nanjing 210008,China
  • Received:2005-02-15 Revised:2005-07-02 Online:2006-04-15 Published:2006-04-15

Abstract:

Changes in land-use may affect the potential of soils to act as a sink for CH4.Samples of lessive,one of the most important soil types in the Sanjiang Plain(45°01′-48°28′N,130°13′-135°05′E,the largest fresh water wetland area in China),were incubated to investigate the effect of land-use change on methane oxidation in lessive.Significant differences between CH4 oxidation rates of all topsoils were found under different land-uses.The highest CH4 oxidation rate was found in natural meadow(dominated by Calamagrostis angustifolia) topsoil,but man-made larch(Larix gmelini) woodland,dry land(wheat or soybean),and paddy field soils reduced CH4 uptake by 64%,98% and 117%,respectively,compared with meadow soil.After the natural meadow was reclaimed,the soil water content(percentage WHC) changed,and the soil organic material decreased.So,the diffusiveness of CH4 and O2 into the soil was reduced and the number and activity of methanotrophic bateria was inhibited.These may be the main reasons for the decrease of methane oxidation in lessives after land-use change.Atmospheric CH4 oxidation activity under all four land uses showed a distinct vertical stratification within the soil profiles.Potential CH4 oxidation rates apparently decreased with the depth in meadow soil and woodland soil, indicating a surface maximum for CH4 oxidation capacity in these soils;the methane uptake rate of the buried organic layer in the dry land soil was 13 times higher than that of the plowed layer.The net productivity of methane was observed in samples of all layers of paddy soil incubated under air,indicating that they had no ability to oxidize atmospheric CH4.Correlation analyses of methane oxidation in lessives and physico-chemical soil parameters yielded significant correlations for the concentrations of organic carbon(r= 0.78, p< 0.01),available N(r= 0.71,p< 0.01) and total N(r= 0.69,p< 0.01),but negative relationships between CH4 uptake rates and pH(r= 0.69,p< 0.01) or water content(percentage WHC)(r= 0.60,p< 0.05) were observed.Linear regression analysis revealed that an individual chemical parameter,soil organic carbon,could be singled out as an indicator for methane oxidation capacity in lessives under certain temperature conditions.

Key words: methane oxidation, methane emission, land-use, lessive