Temporal Stability of Soil Water Contents: A Review of Data and Analyses
- Karl Vanderlindenaf,
- Harry Vereeckenb,
- Horst Hardelaufb,
- Michael Herbstb,
- Gonzalo Martínezcf,
- Michael H. Coshd and
- Yakov A. Pachepsky
IFAPA, Centro Las Torres-Tomejil, 41200 Alcalá del Rio, Spain Agrosphere (IBG-3), Institute of Bio- and Geosciences, Forschungszentrum Jülich GmbH, 52428 Jülich, Germany Dep. of Agronomy, Univ. of Cordoba, 14071, Cordoba, Spain USDA-ARS, Hydrology and Remote Sensing Lab., Beltsville, MD, 20705, USA Pachepsky, USDA-ARS-EMFSL, Beltsville, MD, 20705, USA Currently at USDA-ARS-EMFSL, Beltsville, MD, 20705 USA
This paper reviews the current knowledge base on the temporal stability of soil water contents, highlights the interactions of the temporal stability controls, and proposes research avenues which can advance multiple applications that the temporal stability of soil water contents currently has in environmental monitoring, modeling, and management.
Temporal stability (TS) of soil water content (SWC) has been observed throughout a wide range of spatial and temporal scales. Yet, the evidence with respect to the controlling factors on TS SWC remains contradictory or nonexistent. The objective of this work was to develop the first comprehensive review of methodologies to evaluate TS SWC and to present and analyze an inventory of published data. Statistical analysis of mean relative difference (MRD) data and associated standard deviations (SDRD) from 157 graphs in 37 publications showed a trend for the standard deviation of MRD (SDMRD) to increase with scale, as expected. The MRD followed generally the Gaussian distribution with R2 ranging from 0.841 to 0.998. No relationship between SDMRD and R2 was observed. The smallest R2 values were mostly found for negatively skewed and platykurtic MRD distributions. A new statistical model for temporally stable SWC fields was proposed. The analysis of the published data on seven measurement-, terrain-, and climate-related potentially controlling factors of TS SWC suggested intertwined effects of controlling factors rather than single dominant factors. This calls for a focused research effort on the interactions and effects of measurement design, topography, soil, vegetation and climate on TS SWC. Research avenues are proposed which will lead to a better understanding of the TS phenomenon and ultimately to the identification of the underlying mechanisms.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
Copyright © 2012. . Copyright © by the Soil Science Society of America, Inc.