Review of Soil Water Retention Characteristic (SWRC) Models between Saturation and Oven Dryness

Abstract

Soil water retention characteristic is the key soil property used in many applications in the fields of irrigation, hydrology, geotechnical engineering and soil science in general. Since the advent of digital soil mapping and digital soil assessment paradigms, there has been an upsurge of development of soil inference models and the need to increase accurate application of soil mapping products. All soils can be partially saturated with water and also near oven dryness. Therefore, constitutive models for soils should ideally represent the soil behaviour over entire range. This paper reviewed commonly used SWRC models. In order to stem potential for biasness, the models were grouped into three categories depending on the number of fitting parameters, namely, fiveparameter, four-parameter and three-parameter categories. The evaluation used correlation and residual standard error statistics to choose the best overall performing model and in each category. Its results serve as a guide for selecting the models to be preferred for fitting SWRC in case there are limitations to the number of suction potential levels in the measured data.

Simulation of drip irrigation on slope lands

“…At present there is a large number of functions models [8,9] of soil water retention and moisture conductivity capacity (e.g., such as HYDRUS [10]), but as a rule because of a large array of input constants and statistical calculations validity from physical point of view is hardly to be seen. Soils of the Chuvash Republic (Russia) have poor natural fertility and need external control of soils water regime.…”

Parameter Estimation for Soil Water Retention Curve Using the Salp Swarm Algorithm

“…The method of measuring the SWRC directly can be time-consuming, and improper measurement may lead to greater errors. Thus, mathematical equations to approximate the general form of the SWRC have been suggested, and several different analytical models, including Farrell-Larson [3], Brooks-Corey [4], Fredlund-Xing [3], Gardner [5], van Genuchten [6], Campbell [7], and Russo [8,9] models, have been proposed. These models usually contain several parameters that need to be identified based on collected experimental data.…”

Standardized Drought Indices for Pre-Summer Drought Assessment in Tropical Areas

“…where Q is the emptying of the reservoir, t is the time and α is the emptying coefficient. The emptying coefficient is a critical property of the soil and is complementary to the water retention characteristics of the soil [42], since it indicates the temporal evolution rather than the vertical evolution. Generally, the recession constant corresponds to a decreasing rate of water flow [43,44].…”