Carbon forms and fluxes in different land use systems

增加土壤碳储量对减缓全球气候变化具有重要意义。边际农业用地的改造被认为是增加土壤碳储量的一个可行的选择。然而，土地利用变化，特别是造林，对土壤碳动态的影响是复杂的，知之甚少。在这项研究中，我们将研究四个不同的土地利用系统，农业，草地，森林种植园和原始森林在加拿大西部的草地森林过渡带。我将1）调查土地使用变化对二氧化碳排放的影响（土壤微生物和根系）、甲烷和一氧化二氮，以及它们在每个土地利用系统中产生的全球升温潜能值; 2）评估冬季土壤温室气体（GHG）排放量对年排放量的相对贡献，以及土地利用变化如何影响这一贡献;（3）评估土地利用变化对土壤有机碳形态（包括低分子量有机酸）和底土碳分布的影响;（4）将土壤有机碳形态与土壤碳稳定性联系起来。

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.