CRNS and root zone soil moisture dynamics in agricultural land

CRNS 和农田根区土壤湿度动态

• 批准号: 413992326
• 负责人: Professorin Dr. Sabine Attinger
• 金额: --
• 依托单位: Soil Physics and Land Management Group
• 依托单位国家: 德国
• 项目类别: Research Units
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/413992326?language=en
• 关键词: CRNS; root; zone; soil; moisture

The focus of this project builds on work done in GW in the first phase of the research unit Cosmic Sense which has mainly dealt with the use of CRNS for estimating groundwater recharge and the influence of soil moisture profile shape on CRNS interpretation. Field scale recharge rates at daily basis could be estimated by the use of 1D vadose zone models, and several ways to integrate CRNS within such models were tested. Accompanying measurements were designed and a simple approach developed to compensate for the vertically decreasing sensitivity of the sensor in respect to heterogeneous soil moisture profiles.Within the second phase the research on the influence of different vertical soil moisture distributions on the signal generation and penetration depth of the sensor will be extended for close to natural conditions to highly-managed systems, mainly for an agricultural land use. To achieve this, CRNS measurement will be evaluated, if existing already, or performed at different field sites impacted by shallow groundwater within the CRNS penetration depth or by dedicated artificial sprinkling irrigation experiments in cropped fields. This large band width of vertical soil moisture distributions will be the basis for a systematic assessment of the CRNS penetration depth where related to agricultural applications.The fundamental understanding of vertically heterogeneous distribution of water within the rooted soil profile and the CRNS variable penetration depth will enable to target a more comprehensive view on water storage and fluxes in the rooted soil zone based on CRNS measurements, e.g. at a field site with controlled groundwater table levels and drainage conditions. With that a larger focus shall be set on CRNS and plant-soil interaction, and thus the roots of vegetation as driving water storage changes, being decisive for replenishment of the deeper subsoil layers after drought and groundwater recharge. Also, they themselves are potentially affected by water stress and creating irrigation demands, and its management can be supported by CRNS-based measurements or modeling. Measurements and simulations of soil moisture profiles and its effect on CRNS penetration depth will not only be essential for this project but also for other projects within the research unit because it is fundamental for estimating the full root zone water fluxes and water balance calculations. Resulting soil moisture profiles will be, for example, integrated into the depth scaling approaches of hydrogeodesy, will support the regionalization efforts and better constrain snow water equivalents measured by CRNS. In addition, we will define synthetic soil moisture data sets for testing CRNS interpretation, radiative transfer models and hydrogravimetry approaches at small catchment scale together with other research modules in one of the Cosmic Sense cross-cutting activities, and will be in charge for its overall organization.

该项目的重点是建立在 GW Cosmic Sense 研究单位第一阶段所做的工作的基础上，该研究单位主要涉及使用 CRNS 来估计地下水补给以及土壤湿度剖面形状对 CRNS 解释的影响。每天的现场规模补给率可以通过使用一维包气带模型来估计，并且测试了将 CRNS 集成到此类模型中的几种方法。设计了随附的测量并开发了一种简单的方法，以补偿传感器在异质土壤湿度剖面方面垂直降低的灵敏度。在第二阶段，不同垂直土壤湿度分布对传感器信号生成和穿透深度的影响的研究将扩展到接近自然条件的高度管理系统，主要用于农业用地。为了实现这一目标，将评估 CRNS 测量（如果已经存在），或者在受 CRNS 渗透深度内的浅层地下水影响的不同田地进行评估，或者通过在农作物田地中进行专门的人工喷灌实验。这种垂直土壤湿度分布的大带宽将成为与农业应用相关的 CRNS 渗透深度系统评估的基础。对根土壤剖面内水的垂直异质分布和 CRNS 可变渗透深度的基本了解将有助于基于 CRNS 测量对根土壤区域的水储存和通量有更全面的了解，例如在地下水位和排水条件受控的现场。因此，应更加关注 CRNS 和植物与土壤的相互作用，因此植被根部作为驱动储水变化的因素，对于干旱和地下水补给后深层地下层的补给具有决定性作用。此外，它们本身也可能受到缺水和灌溉需求的影响，并且其管理可以通过基于 CRNS 的测量或建模来支持。土壤湿度剖面的测量和模拟及其对 CRNS 渗透深度的影响不仅对于本项目至关重要，而且对于研究单位内的其他项目也至关重要，因为它对于估计全根区水通量和水平衡计算至关重要。例如，所得的土壤湿度剖面将被整合到水文大地测量学的深度缩放方法中，将支持区域化工作并更好地限制 CRNS 测量的雪水当量。此外，我们将定义合成土壤湿度数据集，用于测试小流域尺度的 CRNS 解释、辐射传输模型和水重测量方法，以及 Cosmic Sense 跨领域活动之一的其他研究模块，并将负责其整体组织。