Stochastic Modeling of Soil Salinity
A minimalist stochastic model of primary soil salinity is proposed, in which
the rate of soil salinization is determined by the balance between dry and wet
salt deposition and the intermittent leaching events caused by rainfall events.
The long term probability density functions of salt mass and concentration are
found by reducing the coupled soil moisture and salt mass balance equation to a
single stochastic differential equation driven by multiplicative Poisson noise.
The novel analytical solutions provide insight on the interplay of the main
soil, plant and climate parameters responsible for long-term soil salinization.
In particular, they show the existence of two distinct regimes, one where the
mean salt mass remains nearly constant (or decreases) with increasing rainfall
frequency, and another where mean salt content increases markedly with
increasing rainfall frequency. As a result, relatively small reductions of
rainfall in drier climates may entail dramatic shifts in long-term soil
salinization trends, with significant consequences e.g. for climate change
impacts on rain-fed agriculture.
Suweis, S; Rinaldo, A; Zee, SEATMVD; Daly, E; Maritan, A; Porporato, A
Geophysical Research Letters
Volume / Issue
Start / End Page
Digital Object Identifier (DOI)