Diffusivity Models and Greenhouse Gases Fluxes from a Forest,Pasture,Grassland and Corn Field in Northern Hokkaido,Japan
Diffusivity Models and Greenhouse Gases Fluxes from a Forest,Pasture,Grassland and Corn Field in Northern Hokkaido,Japan作者机构:Harvard ForestFaculty of Arts and SciencesHarvard University Laboratory of ScienceDivision of Environmental ResourcesGraduate School of Agriculture Hokkaido University Department of GeosciencesSchool of Environmental SciencesFaculty of ScienceNelson Mandela Metropolitan University
出 版 物:《Pedosphere》 (土壤圈(英文版))
年 卷 期:2010年第20卷第6期
页 面:747-760页
核心收录:
学科分类:09[农学] 0818[工学-地质资源与地质工程] 0903[农学-农业资源与环境] 0901[农学-作物学]
基 金:Supported by the Japanese Society for the Promotion of Science (JSPS) the Ministry of Education of Japan (No. PI0701)
主 题:温室气体排放量 扩散系数 预测模型 北海道 玉米田 通量 森林 草地
摘 要:Information on the most influential factors determining gas flux from soils is needed in predictive models for greenhouse gases emissions.We conducted an intensive soil and air sampling along a 2 000 m transect extending from a forest,pasture,grassland and corn field in Shizunai,Hokkaido (Japan),measured CO 2 ,CH 4 ,N 2 O and NO fluxes and calculated soil bulk density (ρ b ),air-filled porosity (f a ) and total porosity (Φ).Using diffusivity models based on either f a alone or on a combination of f a and Φ,we predicted two pore space indices: the relative gas diffusion coefficient (D s /D o ) and the pore tortuosity factor (τ).The relationships between pore space indices (D s /D o and τ) and CO 2 ,CH 4 ,N 2 O and NO fluxes were also studied.Results showed that the grassland had the highest ρ b while f a and Φ were the highest in the forest.CO 2 ,CH 4 ,N 2 O and NO fluxes were the highest in the grassland while N 2 O dominated in the corn field.Few correlations existed between f a ,Φ,ρ b and gases fluxes while all models predicted that D s /D o and τ significantly correlated with CO 2 and CH 4 with correlation coefficient (r) ranging from 0.20 to 0.80.Overall,diffusivity models based on f a alone gave higher D s /D o ,lower τ,and higher R 2 and better explained the relationship between pore space indices (D s /D o and τ) and gases fluxes.Inclusion of D s /D o and τ in predictive models will improve our understanding of the dynamics of greenhouse gas fluxes from soils.D s /D o and τ can be easily obtained by measurements of soil air and water and existing diffusivity models.