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

土壤水分和热量是作物生产、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途径和命运，例如流入河流或湖泊、渗入地下水、排放到大气或被植物吸收。一般来说，由于土壤水和热状态在冻结和融化期间的瞬态性质，对非平坦景观的土壤水和热状态进行量化需要频繁的空间和时间测量。缺乏快速有效的测量方法阻碍了我们对坡地土壤水动力学和热状态的理解。此外，在寒冷地区，冻结和解冻使液体和冰水在土壤中共存。申请人在五个典型景观和水文单位设有五个监测站，监测水文过程。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。介绍了一种多用途热脉冲探头（MPHPP）。MPHPPs可以测量液态土壤含水量、冰含量、土壤热容、热扩散系数、土壤温度和土壤电导率。MPHPPs可以同时跟踪相同体积下土壤水分、热状态和盐浓度的瞬态变化。MPHPPs可以在我们的实验室以有限的成本建造。然而，由于需要在短时间内进行大量的多组分测量，因此需要一种快速的多通道数据记录仪CR9000XC来实现多深度MPHPP测量的自动化。拟议的研究将是对五个景观位置和水文单位现有水文监测基础设施的重要补充。频繁和准确地测量土壤含水量和热状态对于理解水文过程的机制至关重要，而水文过程对作物水分利用效率和野生动物栖息地至关重要。了解水动力学、热制度是提高农业生态系统用水效率和环境质量的先决条件，因此也是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.