Measurement of soil water characteristic curve using HYPROP2

Soil water characteristic curve (SWCC) has an important application in drainage, irrigation, soil physical behavior, and modeling hydrology and nutrient transport. However, measurement of the SWCC is often very time consuming, inaccurate and requires a lot of effort. In order to determine an accurate SWCC, we used HYPROP2. This method article extensively describes the topics which were not covered well by the instrument's manual such as collecting soil samples, use of the HYPROP refill unit, degassing water prior to degassing the tensio shafts and other procedures. Advice is provided in terms of better handling of the equipment to receive all four phases of an optimal measuring curve. Following the step-by-step procedure mentioned in this article would provide a high-quality SWCC. Our measurements were performed on both clay loam and sandy loam soils to show differences in the SWCC. We found that the upper tensio shaft took longer to cavitate for sandy loam soil compared to the clay loam soil. • This paper describes an efficient and accurate method to determine the SWCC using HYPROP2. • This method showed quick and reliable measurements of SWCC for a clay loam and sandy loam soil. • This method includes procedure for soil sample collection and laboratory analysis with HYPROP2.