TY - JOUR
T1 - Hysteresis in soil hydraulic conductivity as driven by salinity and sodicity-a modeling framework
AU - Kramer, Isaac
AU - Bayer, Yuval
AU - Adeyemo, Taiwo
AU - Mau, Yair
N1 - Publisher Copyright:
© 2021 Copernicus GmbH. All rights reserved.
PY - 2021/4/14
Y1 - 2021/4/14
N2 - Declining soil-saturated hydraulic conductivity (Ks) as a result of saline and sodic irrigation water is a major cause of soil degradation. While it is understood that the mechanisms that lead to degradation can cause irreversible changes in Ks, existing models do not account for hysteresis between the degradation and rehabilitation processes.We develop the first model for the effect of saline and sodic water on Ks that explicitly includes hysteresis. As such, the idea that a soil s history of degradation and rehabilitation determines its future Ks lies at the center of this model. By means of a "weight" function, the model accounts for soil-specific differences, such as clay content. The weight function also determines the form of the hysteresis curves, which are not restricted to a single shape, as in some existing models for irreversible soil processes. The concept of the weight function is used to develop a reversibility index, which allows for the quantitative comparison of different soils and their susceptibility to irreversible degradation. We discuss the experimental setup required to find a soil s weight function and show how the weight function determines the degree to which Ks is reversible for a given soil. We demonstrate the feasibility of this procedure by presenting experimental results showcasing the presence of hysteresis in soil Ks and using these results to calculate a weight function. Past experiments and models on the decline of Ks due to salinity and sodicity focus on degradation alone, ignoring any characterization of the degree to which declines in Ks are reversible. Our model and experimental results emphasize the need to measure "reversal curves", which are obtained from rehabilitation measurements following mild declines in Ks. The developed model has the potential to significantly improve our ability to assess the risk of soil degradation by allowing for the consideration of how the accumulation of small degradation events can cause significant land degradation.
AB - Declining soil-saturated hydraulic conductivity (Ks) as a result of saline and sodic irrigation water is a major cause of soil degradation. While it is understood that the mechanisms that lead to degradation can cause irreversible changes in Ks, existing models do not account for hysteresis between the degradation and rehabilitation processes.We develop the first model for the effect of saline and sodic water on Ks that explicitly includes hysteresis. As such, the idea that a soil s history of degradation and rehabilitation determines its future Ks lies at the center of this model. By means of a "weight" function, the model accounts for soil-specific differences, such as clay content. The weight function also determines the form of the hysteresis curves, which are not restricted to a single shape, as in some existing models for irreversible soil processes. The concept of the weight function is used to develop a reversibility index, which allows for the quantitative comparison of different soils and their susceptibility to irreversible degradation. We discuss the experimental setup required to find a soil s weight function and show how the weight function determines the degree to which Ks is reversible for a given soil. We demonstrate the feasibility of this procedure by presenting experimental results showcasing the presence of hysteresis in soil Ks and using these results to calculate a weight function. Past experiments and models on the decline of Ks due to salinity and sodicity focus on degradation alone, ignoring any characterization of the degree to which declines in Ks are reversible. Our model and experimental results emphasize the need to measure "reversal curves", which are obtained from rehabilitation measurements following mild declines in Ks. The developed model has the potential to significantly improve our ability to assess the risk of soil degradation by allowing for the consideration of how the accumulation of small degradation events can cause significant land degradation.
UR - http://www.scopus.com/inward/record.url?scp=85104197421&partnerID=8YFLogxK
U2 - 10.5194/hess-25-1993-2021
DO - 10.5194/hess-25-1993-2021
M3 - ???researchoutput.researchoutputtypes.contributiontojournal.article???
AN - SCOPUS:85104197421
SN - 1027-5606
VL - 25
SP - 1993
EP - 2008
JO - Hydrology and Earth System Sciences
JF - Hydrology and Earth System Sciences
IS - 4
ER -