Linking biological drivers and water transport to understand biodiversity effects on C and N storage in soils

为了更好地理解生物多样性生态系统功能(BEF)的关系，强调了在生物多样性研究中进行长期观察和实验的必要性。对于土壤等反应缓慢的系统尤其如此，在研究驱动次土壤中元素动力学的过程时甚至更是如此。因此，拟议的项目将在实验建立10年后调查植物多样性和组成对亚土壤(40厘米以下)有机质变化的影响。我们探索C和N土壤动态与水分循环的耦合，以揭示植物多样性影响氮素在土壤深度剖面上获得、损失和再分配的潜在机制。除了了解更深层的土壤过程外，这项工作还将有助于理解为什么在未施肥的耶拿实验中，氮素在表层土壤中积累。最后，我们将与其他新成立的子项目密切合作，探索土壤相关过程的正BEF关系，不仅研究植物多样性对元素循环的影响，还研究相关驱动因素随时间的变化。最后一点将得到来自长期生物多样性对生态系统功能影响的决定因素(DELT BEF)实验的深刻见解的有力支持，在该实验中，我们确定了不同土壤历史的土壤碳、氮储量和储量，以及土壤水分模式。

The need for long term observations and experiments in biodiversity research has been emphasized to better understand biodiversity ecosystem functioning (BEF) relationships. This is particular true for slowly reacting systems, such as soil and even more when investigating processes driving element dynamics in sub soils. The proposed project will therefore investigate the effect of plant diversity and composition on organic matter changes in sub soils (deeper than 40 cm) ten years after establishing the experiment. We explore the coupling of C and N soil dynamics with the water cycle in order to reveal the underlying mechanisms governing plant diversity effects on nitrogen gains, losses and redistribution along a soil depth profile. Besides understanding deeper soil processes, this work will also contribute to understand why N accumulates in the topsoil of the non fertilized Jena Experiment. Finally, in close cooperation with the other newly formed subprojects, we will explore the positive BEF relationship for soil related processes to investigate not only the effect of plant diversity on element cycles but also the shift of the related drivers over time. The last point will be strongly supported by the insights derived from the Determinants of LongTerm Biodiversity Effects on Ecosystem Functioning (DeLT BEF) Experiment, where we determine soil carbon and nitrogen stocks and storage, and soil moisture patterns in soils having different soil history.