Comparison of Three Commonly Used Concepts in Explaining Soil Water Availability for Plants (CPAW, EI and Mh0) and Their Feasibility as an Indicator of Soil Management

Document Type : Research Paper

Authors

1 Ph.D student, , Department of Soil Science and Engineering, Faculty of Agricultural Engineering and Technology, University of Tehran, Iran

2 Associate Professor, Department of Soil Science and Engineering, Faculty of Agricultural Engineering and Technology, University of Tehran, Iran

Abstract

The complexity of the concept of soil water availability has led to the emergence of a variety of methods to estimate it, which have always been changing, refining, and replacing. Among those, the conventional method of plant available water (CPAW=FC-PWP) due to convenient measurement has received more attention. In theory, however, the methods of Integral Energy (EI) and Kirchhoff Potential (Mh0) have been considered due to the interference of soil properties and plant ability for water uptake. In this  study, the available water was calculated with CPAW, E­I and Mh0 concepts in a wide range of soils (72 samples) with various physical properties and results were compared. Also, different upper limits were tested to determine the water availability and the new field capacity moisture coefficient was used as the upper limit of the concept of water availability. Despite the weak correlation between EI and Mh0, the trend of their variations in different soils is somewhat similar, indicating their similarity in the estimation of available water for plants. In contrast, the lack of a clear relationship between EI and Mh0 with CPAW confirmed their lack of correlation in explaining water availability of the plant. The convenience of using CPAW makes it even more preferable to study the variability of soils in terms of hydraulic properties. On the other hand, the use of EI and Mh0 results will be useful for explaining the available water content but still needs to be modified in terms of determining threshold limits.

Keywords


Armindo, R. A., & Wendroth, O. (2016). Physical soil structure evaluation based on hydraulic energy functions. Soil Science Society of America Journal80(5), 1167-1180.
Assouline, S., & Or, D. (2014). The concept of field capacity revisited: Defining intrinsic static and dynamic criteria for soil internal drainage dynamics. Water Resources Research50(6), 4787-4802.
Colman, E. A. (1947). A laboratory procdure for determining the field capacity of soils. Soil Science63(4), 277-284.
Da Silva, A. P., Kay, B. D., & Perfect, E. (1994). Characterization of the least limiting water range of soils. Soil Science Society of America Journal58(6), 1775-1781.
Groenevelt, P. H., Grant, C. D., & Semetsa, S. (2001). A new procedure to determine soil water availability. Soil Research39(3), 577-598.
Hillel, D. (1998). Environmental soil physics: Fundamentals, applications, and environmental considerations. Elsevier.
Kirkham, M. B. (2014). Principles of soil and plant water.
Letey, J. O. H. N. (1958). Relationship between soil physical properties and crop production. In Advances in soil science(pp. 277-294). Springer, New York, NY.
Meskini-Vishkaee, F., Mohammadi, M. H., & Neyshabouri, M. R. (2018). Revisiting the wet and dry ends of soil integral water capacity using soil and plant properties. Soil Research56(4), 331-345.
Minasny, B., & McBratney, A. B. (2003). Integral energy as a measure of soil-water availability. Plant and Soil249(2), 253-262.
Mualem, Y. (1986). Hydraulic conductivity of unsaturated soils: prediction and formulas. Methods of Soil Analysis: Part 1—Physical and Mineralogical Methods, (methodsofsoilan1), 799-823.
Nachabe, M. H. (1998). Refining the definition of field capacity in the literature. Journal of irrigation and drainage engineering124(4), 230-232.
Nemes, A., Pachepsky, Y. A., & Timlin, D. J. (2011). Toward improving global estimates of field soil water capacity. Soil Science Society of America Journal75(3), 807-812.
Nemes, A.D., Schaap, M.G., Leij, F.J. and Wösten, J.H.M., 2001. Description of the unsaturated soil hydraulic database UNSODA version 2.0. Journal of Hydrology251(3-4), pp.151-162.
Philip, J. R. (1972). Future problems of soil water research. Soil Science113(4), 294-301.
Timlin, D., Pachepsky, Y., & Reddy, V. R. (2001). Soil water dynamics in row and interrow positions in soybean (Glycine max L.). Plant and Soil237(1), 25-35.
Twarakavi, N. K., Sakai, M., & Šimůnek, J. (2009). An objective analysis of the dynamic nature of field capacity. Water Resources Research45(10).
Van Dam, J. C., & Feddes, R. A. (2000). Numerical simulation of infiltration, evaporation and shallow groundwater levels with the Richards equation. Journal of Hydrology233(1-4), 72-85.
van Genuchten, M. T. (1980). A closed-form equation for predicting the hydraulic conductivity of unsaturated soils 1. Soil science society of America journal44(5), 892-898.
van Genuchten, M.V., Leij, F.J. and Yates, S.R., 1991. The RETC code for quantifying the hydraulic functions of unsaturated soils.
Van Lier, Q. D. J. (2017). Field capacity, a valid upper limit of crop available water. Agricultural water management193, 214-220.
Van Lier, Q. D. J., & Wendroth, O. (2016). Reexamination of the field capacity concept in a Brazilian Oxisol. Soil Science Society of America Journal80(2), 264-274.
Van Lier, Q. D. J., Metselaar, K., & Van Dam, J. C. (2006). Root water extraction and limiting soil hydraulic conditions estimated by numerical simulation. Vadose Zone Journal5(4), 1264-1277.