The human dimension of pedogenesis and soil organic matter accumulation at grazed and pristine sites in the High Andes

人类利用土地对环境的影响在全球范围内引起土壤发育的重大变化，并造成陆地生态系统碳的严重损失。除了缓慢的净变化，土壤有机质是最重要的生态系统碳库之一，由于高库存。目前的证据表明，大气中二氧化碳的土壤源或汇的大小与土壤性质有关，而土壤性质是由成土过程演变而来的。然而，土地利用和碳固存尚未与成土作用适当联系起来。一个原因是缺乏合适的参考地点，可以明确地被指定为原始的，但提供与人类使用的地点相当的条件。我们已经在秘鲁安第斯山脉的库斯科地区的偏远山脉上发现了这样的原始遗址。这些地方只能通过登山设备进入，但靠近几千年来一直在广泛放牧管理的地点。我们假设，（a）土地利用和相关的植被变化影响土壤发生，导致不同的分类单位的原始和扰动土壤和（B）土地利用和改变土壤发生改变的相对重要性的特定机制稳定土壤有机质。为了解决这些假设，将使用土壤分类和土壤发育指数，并将其与土壤有机质在不同机制稳定的组分中的分布联系起来。将土壤发生与土壤有机质稳定性联系起来，将提高我们对人类对碳固存影响的理解，并可能有助于加强土地利用变化引起的碳向大气流失的缓解战略。

Human impact on the environment by land use has globally induced major changes in soil development and caused severe losses of carbon from terrestrial ecosystems. Besides slow net changes, soil organic matter is one of the most important ecosystem carbon reservoirs due to the high stocks. Current evidence suggests that the size of the source or sink of soil for atmospheric carbon dioxide is linked to soil properties, which evolve from pedogenetic processes. However, land use and carbon sequestration have not yet been properly linked with pedogenesis. One reason is the lack of suitable reference sites that can clearly be assigned as pristine, but offer conditions comparable to sites used by humans. We have identified such pristine sites in the Cusco region of the Peruvian Andes on remote mountain ledges. These are only accessible with mountaineering equipment but are close to sites which have been under extensive grazing management for several millennia. We hypothesise that (a) Land use and associated vegetation change affected soil genesis, leading to different classification units of pristine and disturbed soils and (b) land use and altered soil genesis changed the relative importance of the particular mechanisms stabilising soil organic matter. To address these hypotheses, soil classification and soil development indices will be used and linked to the distribution of soil organic matter among fractions that are stabilised by different mechanisms. Linking aspects of soil genesis with soil organic matter stabilisation will enhance our understanding of the human impact on carbon sequestration and may help to enhance mitigation strategies for land use change induced losses of carbon to the atmosphere.