Coevolution of Aeolian Landscapes and Soils

该项目将重点关注大平原上草稳定的沙丘和黄土景观（有厚厚的风沙沉积物的地区），以确定过去塑造这些景观的过程将如何影响它们对未来气候变化的反应，特别是更频繁的严重干旱或强降雨。这项研究将测试数百年至数千年的土壤形成，包括有机物和细粉尘的积累，是否能显著降低这些景观的某些部分对风和水侵蚀的敏感性。这些结果对于预测未来加速侵蚀和沙丘活化的模式具有重要意义，具有重大的实际意义，因为黄土景观的平坦高原是主要的农业用地，而沙丘是重要的牧场和奥加拉拉含水层的关键补给区。侵蚀的增加也会影响河流的沉积物输入，并释放这些景观中埋藏和表层土壤中储存的碳。该项目将为不同的学生群体提供研究培训，并将开发有效的方法，将研究结果传达给当地社区和其他利益相关者。该项目将检验黄土高原和邻近沙丘地演变过程中地貌过程与土壤形成之间相互作用的假设。这些假设认为，风成过程（风蚀、缓慢黄土堆积和沙丘活动）影响土壤形成和有机碳积累的空间格局，进而通过对植被恢复力和机械强度的影响影响风蚀和水蚀阈值。研究地点的选择将允许比较具有不同土壤发育和近期黄土堆积的高原峰顶和邻近斜坡以及具有不同土壤发育的沙丘上与养分和水分可用性和抗剪强度相关的土壤和沉积物特性。野外和实验室测量将结合土壤水文模型、地理空间分析和发光测年。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

This project will focus on grass-stabilized sand dunes and loess landscapes (areas of thick wind-blown dust deposits) in the Great Plains, to determine how processes that shaped these landscapes in the past will influence their response to future climate change, especially more frequent severe drought or heavy rainfall. The research will test whether soil formation over hundreds to thousands of years, including accumulation of organic matter and fine dust, can significantly reduce the susceptibility of certain parts of these landscapes to wind and water erosion. The results will be important for predicting patterns of future accelerated erosion and dune activation, with major practical implications, since the level tablelands of the loess landscapes are prime agricultural land and the dunes are important rangeland and key recharge areas for the Ogallala Aquifer. Increased erosion could also affect sediment input to streams and release carbon stored in buried and surface soils in these landscapes. The project will provide research training to a diverse group of students and will include development of effective ways to communicate the results to local communities and other stakeholders.The project will test hypotheses on the interactions between geomorphic processes and soil formation in the evolution of loess tablelands and adjacent dune fields. The hypotheses propose that aeolian processes (deflation, slow loess accumulation, and dune activity) influence spatial patterns of soil formation and organic carbon accumulation, which in turn influence thresholds for wind and water erosion through effects on vegetation resilience and mechanical strength. Study sites will be selected to allow comparison of soil and sediment properties related to nutrient and water availability and shear strength on tableland summits and adjacent slopes with varying soil development and recent loess accumulation, and on dunes with varying soil development. Field and lab measurements will be combined with modeling of soil hydrology, geospatial analyses, and luminescence dating.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.