Multifractal behaviour of the soil water content of a vineyard in northwest Spain during two growing seasons

Abstract

Abstract. Soil processes are characterized by a great degree of heterogeneity, which may be assessed by scaling properties. The aims of the current study were to describe the dynamics of soil water content at three depths in a vineyard under rain-fed and irrigation conditions and to assess the multifractality of these time data series. Frequency domain reflectometry (FDR) sensors were used for automatically monitoring soil water content in a vineyard located in Leiro (Ourense, northwest Spain). Data were registered at 30 min intervals at three depths (20, 40, and 60 cm) between 14 June and 26 August 2011 and 2012. Two treatments were considered: rain-fed and irrigation to 50 % crop evapotranspiration. Soil water content data series obeyed power laws and tended to behave as multifractals. Values for entropy (D1) and correlation (D2) dimensions were lower in the series from the irrigation treatment. The Hölder exponent of order zero (α0) was similar between treatments; however, the widths of the singularity spectra, f(α), were greater under irrigation conditions. Multifractality indices slightly decreased with depth. These results suggest that singularity and Rényi spectra were useful for characterizing the time variability of soil water content, distinguishing patterns among series registered under rain-fed and irrigation treatments.

Persistence and Corresponding Time Scales of Soil Moisture Dynamics During Summer in the Babao River Basin, Northwest China

“…Whether soil moisture exhibits a long-range correlation or antipersistence, corresponding time window sizes are defined as corresponding time scales. Fractal or multifractal behaviors have often been studied to describe soil moisture dynamics (Gao et al, 2015;Guerrini & Swartzendruber, 1997;Mirás-Avalos et al, 2016). Various studies (e.g., R. Song et al, 2011;Gao et al, 2015;Ji et al, 2016;Mirás-Avalos et al, 2016) have focused on the features (e.g., fractal dimensions and long-range correlations) of soil moisture dynamics.…”

“…Fractal or multifractal behaviors have often been studied to describe soil moisture dynamics (Gao et al, 2015;Guerrini & Swartzendruber, 1997;Mirás-Avalos et al, 2016). Various studies (e.g., R. Song et al, 2011;Gao et al, 2015;Ji et al, 2016;Mirás-Avalos et al, 2016) have focused on the features (e.g., fractal dimensions and long-range correlations) of soil moisture dynamics. Various studies demonstrate that soil moisture dynamics present significant long-range correlations in different areas (Gao et al, 2015;R.…”

“…It is also necessary to enhance the description, investigation, and understanding of soil moisture persistence and of corresponding time scale to improve the accuracies of soil moisture simulations using linear models or models considering nonlinearity, as soil moisture is clearly nonlinear and complex over time when coupled with environmental factors and processes (Mirás‐Avalos et al, ). First, the soil water diffusivity, which is illustrated by fractional Brownian motion, follows a nonrandom, nonstationary process and fractal behavior (Guerrini & Swartzendruber, ).…”

Long‐range correlations of soil water content time series under tillage and different cover crops in a semi‐arid vineyard

“…Other authors found that multifractal analysis of SWC time series allowed discrimination among SWC patterns in a vineyard with two treatments, irrigated and rainfed (Mirás‐Avalos, Trigo‐Córdoba, da Silva‐Dias, Varela‐Vila, & García‐Tomillo, 2016). In our conditions, the effect of treatment should be related to the fact that both cover crops caused greater soil water evapotranspiration in the vineyard.…”

Localized Learning of Downscaled Soil Moisture

“…Fortunately, many other systems also demonstrate a multifractal characteristic. Mirás-Avalos et al [7] characterized this lack of homogeneity in soil moisture storage as a complex function of multiple nested processes "related to topographical, geological, edaphic, and vegetation factors." As soil moisture distribution is linked strongly to these independent variables, it can be hypothesized that these attributes can also represent the self-affine fractal qualities of moisture distribution in their own spatial organization.…”