EFFECTS OF NUTRIENTS & SOIL CONDITIONS ON ROOT DISTRIBUTION IN INTACT SOIL CORES

土壤固有的不透明性使得对 地下生物过程极其困难。 传统 方法包括物理挖掘和土壤筛分以及 人工观察表面的强加，例如与 根管和微型电子管。 这些技术要么破坏 根在土壤中的几何形状，或者通过强迫 根沿着玻璃或塑料表面生长。 东南部的许多土壤 美国支持松树种植园是轻桑迪壤土， 纹理与先前MR成像中使用的砂样相似 实验 MR方法的发展，以确定功能，生活 根在土壤核心将提供一个强大的新工具， 地下过程的研究。 根相对于 X-Y平面尤其重要，因为大多数营养矿化 发生在土壤表层10厘米处。 此外，说明 分支模式将允许研究根之间的关系， 结构和养分有效性。 理解 根系生产与地下C分配的关系 通过根系获取资源是目前一个非常重要的话题， 对评估植物对全球变化的反应感兴趣， 森林为预测的升高水平提供汇的潜力 二氧化碳。 我建议开发成像协议，使用传统的 3-Dspin回波技术，用于观察完整田间土壤中的活根 丹 将从美国农业部抽取有限数量的岩芯。 林务局网站在苏格兰县，并成像。 然后，核心将 被解剖，并确定核心内的根源。 条件 恢复的根段将被记录，并与 在MR图像集中检测它们的能力。 核心直径将 8 cm，完全在当前图像采集的尺寸范围内 协议.

The inherently opaque nature of soil has made the study of belowground biological processes extremely difficult. Traditional methods include physical excavation and sieving of soil as well as the imposition of artificial viewing surfaces such as are used with rhizotrons and minirhizotrons. These techniques either destroy the geometry of the roots within the soil, or create artifacts by forcing roots to grow along a glass or plastic surface. Many soils of the SE United States supporting pine plantations are light sandy loams, similar in texture to the sand samples used in previous MR imaging experiments. Development of MR methods to identify functional, living roots within soil cores would provide a powerful new tool for the study of belowground processes. The orientation of roots relative to the X-Y plane is especially important, as most nutrient mineralization occurs within the top 10 cm of soil. In addition, description of branching patterns will allow study of the relationship between root architecture and nutrient availability. Understanding of the relationship between belowground C allocation through root production and resource acquisition by roots is currently a topic of great interest in evaluating plant response to global change, and the potential for forests to provide a sink for predicted elevated levels of CO2. I propose to develop imaging protocols, using traditional 3-Dspin echo techniques, to view living roots within intact field soil cores. A limited number of cores will be sampled from the U.S.D.A. Forest Service site in Scotland County, and imaged. Cores will then be dissected, and roots within the core identified. Condition of the recovered root segments will be recorded, and correlated with the ability to detect them within the MR image sets. Core diameter will be 8 cm, well within the size range for current image acquisition protocols.