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

人类通过土地利用对环境的影响在全球范围内引起了土壤发育的重大变化，并造成了陆地生态系统碳的严重损失。除了缓慢的净变化外，土壤有机质由于储量大，是生态系统中最重要的碳库之一。目前的证据表明，大气二氧化碳的土壤源或汇的大小与土壤性质有关，土壤性质是由成土过程演变而来的。然而，尚未将土地利用和碳固存与成土作用适当地联系起来。一个原因是缺乏合适的参考地点，可以明确地指定为原始，但提供可与人类使用的地点相媲美的条件。我们已经在秘鲁安第斯山脉的库斯科地区的偏远山区边缘发现了这样的原始遗址。只有带着登山设备才能进入，但这些地方靠近几千年来一直处于大规模放牧管理之下的遗址。我们假设：(a)土地利用和相关植被变化影响土壤成因，导致原始土壤和受干扰土壤的不同分类单位；(b)土地利用和改变的土壤成因改变了稳定土壤有机质的特定机制的相对重要性。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由不同机制稳定的组分之间的分布联系起来。将土壤发生的各个方面与土壤有机质稳定联系起来，将增进我们对人类对碳固存的影响的理解，并可能有助于加强缓解土地利用变化引起的碳向大气损失的战略。

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.