A novel research tool for simultaneous measurement of liquid and ice soil water contents, soil thermal properties and electrical conductivity

土壤水热是作物生产、洪水、径流和土壤温室气体排放的关键变量。它们还直接影响农用化学品或废物的路径和归宿，如流入河流或湖泊、渗入地下水、排放到大气中或被植物吸收。一般来说，量化土壤水分和热状况在非水平景观需要频繁的测量空间和时间，因为土壤水分和热状况的瞬态性质，特别是在冻结和解冻。缺乏快速有效的测量方法阻碍了我们对坡地土壤水分动态和热状况的了解。此外，在寒冷地区，冻融使液体和冰水共存于土壤中。申请方在五个典型地貌和水文单元中有五个水文过程监测站。然而，缺乏监测与水文过程交织在一起的土壤热特性制度的设施。最近，一种多用途热脉冲探头（MPHPP）被引入。MPHPP可以测量液态土壤含水量和冰含量，以及土壤热容，热扩散率，土壤温度和土壤电导率。MPHPP允许跟踪土壤水分，热状况和盐浓度在同一时间在同一体积中的瞬态变化。MPHPP可以在我们的实验室中以有限的成本建造。然而，由于需要在短时间内进行大量的多分量测量，因此需要快速多通道数据记录器CR9000XC，以便在多个深度处自动进行MPHPP测量。 拟议的研究将是对五个地貌位置和水文单位现有水文监测基础设施的重要补充。土壤水分含量和温度状况的频繁和准确的测量是至关重要的，以了解水文过程的机制，是作物水分利用效率和野生动物栖息地的关键。了解水动力学和热状况是提高农业生态系统的用水效率和环境质量，从而提高加拿大人健康的先决条件。

Soil water and heat are key variables in crop production, flooding, runoff, and greenhouse gas emission from soils. They also directly affect the pathway and fate of agrochemicals or wastes, such as runoff to rivers or lakes, leaching to groundwater, emission to the atmosphere, or uptake by plants. Generally, quantifying soil water and thermal regimes in non-level landscapes needs frequent measurements in space and time because of the transient nature of soil water and thermal regimes particularly during freezing and thawing. The lack of fast and efficient measurement methods hinders our understanding of soil water dynamics and thermal regimes in sloping landscapes. Further, in cold regions, freezing and thawing make liquid and ice water coexist in soil. The applicant has five stations for monitoring hydrological processes in the five typical landscape and hydrological units. However, there is a lack of facility for monitoring soil thermal properties regime that are intertwined with hydrological processes. Recently, a multipurpose heat pulse probe (MPHPP) was introduced. The MPHPPs can measure liquid soil water content, and ice content, as well as soil heat capacity, thermal diffusivity, soil temperature and soil electrical conductivity. MPHPPs allow tracking the transient changes in soil water, thermal regimes, and salt concentration in the same volume at the same time. The MPHPPs can be built in our laboratory with limited cost. However, because of a large amount of multi-component measurements to be taken in a short time, a rapid and multi-channel datalogger, CR9000XC, is needed in order to automate the MPHPP measurements at multiple depths.  The proposed research would be an important addition to the available hydrological monitoring infrastructure at the five landscape positions and hydrological units. The frequent and accurate measurement of soil water contents and thermal regimes is critical to understanding the mechanisms of hydrological processes that are critical for crop water use efficiency and wildlife habitats. An understanding of water dynamics, thermal regimes, is a prerequisite for improving the water use efficiency and environmental quality of agri-ecosystems, and consequently the health of Canadians.