Carbon forms and fluxes in different land use systems

增加土壤中的碳(C)储量对于减缓快速变化的全球气候非常重要。边际农业用地造林被认为是增加土壤碳储量的可行选择。然而，土地利用变化，特别是造林，对土壤C动态的影响是复杂的，而且知之甚少。在这项研究中，我们将研究四种不同的土地利用系统，农业，草地，人工林和原生林在整个加拿大西部的草地-森林过渡带。我将1)调查土地利用变化对二氧化碳（土壤微生物和根系）、甲烷和一氧化二氮排放的影响，以及它们在每个土地利用系统中导致的全球变暖潜势；2)评估冬季土壤温室气体（GHG）排放对年排放的相对贡献及其受土地利用变化的影响，有助于了解不同土地利用系统的年温室气体总通量；3)评价土地利用变化对土壤有机碳形态（包括低分子量有机酸）和土壤碳分布的影响；4)土壤有机碳形态与土壤碳稳定性的关系。

To increase carbon (C) storage in the soil is important for mitigating the rapidly changing global climate. Afforestation of marginal agricultural land is considered a viable option for increasing soil C storage. However, the effects of land use change, afforestation in particular, on soil C dynamics are complex and poorly understood. In this research we will study four different land use systems, agricultural, grassland, forest plantation and native forests in the grassland-forest transition zone across western Canada. I will 1) investigate the effect of land use change on the emission of carbon dioxide (both by soil microbial organisms and by roots), methane and nitrous oxide, and their resulting global warming potential in each land use system; 2) evaluate the relative contribution of winter soil greenhouse gas (GHG) emissions to annual emissions and how that is affected by land use change, to help understand the total annual GHG fluxes of the different land use systems; 3) evaluate the effects of land use change on soil organic C forms, including low molecular weight organic acids, and C distribution in the subsoil; and 4) relate soil organic C form to soil C stability.