Collaborative Research: Detecting Spatial Patterns of Dust Effects on Soils: Testing New Methodology in the Central Great Plains

本项目将以大平原中部为研究区域，研究大气沙尘沉降对土壤变化区域空间格局的影响。在大平原上，就像在许多其他干旱到半湿润的地区一样，有地质证据和现代文献表明反复出现的区域粉尘运输和沉积。在全新世期间，沙尘沉降速率高，形成了不同的黄土沉积。在更大的区域内，沉积速度较慢的灰尘可能已被纳入正在形成的土壤剖面。该项目的关键新元素是利用横跨大平原中部的采样点网络，重点检测指示尘埃运输的区域空间模式。粉尘沉积速率、颗粒大小和矿物学随距离粉尘源的远近而有系统地变化。这些趋势应反映在土壤形态和矿物学的区域空间格局中，与全新世主要来源的“羽状”粉尘扩散相对应。将在每个地点取样多个土壤剖面，以量化当地的变异性。从区域采样网络中，研究人员将选择具有代表性的土壤，用于对土壤发育过程中粉尘添加的矿物学和地球化学证据进行更详细的调查。这个项目将检验可以更广泛地应用于土壤科学基本问题的方法，这些方法适用于受经常性粉尘产生和沉积影响的景观。人们普遍认为粉尘沉积是土壤形成的重要过程，但以往的研究大多没有关注粉尘对土壤影响的广泛区域模式。这些空间模式是将尘埃效应纳入我们对重要土壤相关环境问题理解的关键。例如，土壤储存有机碳的潜力是预测和减轻人类引起的全球碳循环变化的一个重要问题。粉尘沉降可能影响土壤碳储量潜力的区域格局，因为添加的粉尘可以改变土壤性质，而土壤性质对碳储量有很大影响。由于该项目将对一个区域土壤网络进行采样，其结果将直接适用于绘制一个大区域的土壤碳储存潜力。该项目的结果还将有助于解释作为过去气候变化重要指标的埋藏土壤。

This project will investigate the role of atmospheric dust deposition in creating regional spatial patterns of soil variation, using a study area in the central Great Plains. On the Great Plains, as in many other arid to subhumid landscapes, there is both geologic evidence and modern documentation of recurrent regional dust transport and deposition. During the Holocene, dust deposition at high rates produced distinct loess deposits in scattered localities in this region. More slowly deposited dust may have been incorporated into developing soil profiles over much larger areas. The key new element in this project is the focus on detecting regional spatial patterns indicative of dust transport, using a network of sampling sites across the central Great Plains. Dust deposition rate, grain size, and mineralogy vary systematically with distance from the source. These trends should be reflected in regional spatial patterns of soil morphology and mineralogy corresponding to "plumes" of Holocene dust dispersal from major sources. Multiple soil profiles will be sampled at each site to quantify local variability. From the regional sampling network, the investigators will select representative soils to use in more detailed investigations of the mineralogical and geochemical evidence for dust addition during soil development.This project will test methodology that can be much more broadly applied to a basic problem of soil science, in landscapes affected by recurrent dust production and deposition. Dust deposition is widely recognized as an important process in soil formation, but most previous studies have not focused on broad regional patterns of dust effects on soils. These spatial patterns are the key to incorporating dust effects into our understanding of important soil-related environmental issues. For example, the potential of soils to store organic carbon is an important issue in efforts to predict and mitigate human-induced changes in the global carbon cycle. Dust deposition may affect regional patterns of soil carbon storage potential because the added dust can change soil properties that strongly influence carbon storage. Because this project will sample a regional network of soils, the results will be directly applicable to mapping soil carbon storage potential over a large region. Results of this project will also help interpret buried soils that are important indicators of past climate change.