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ARS Home » Northeast Area » Beltsville, Maryland (BARC) » Beltsville Agricultural Research Center » Environmental Microbial & Food Safety Laboratory » Research » Publications at this Location » Publication #331218
Research Project: Design and Implementation of Monitoring and Modeling Methods to Evaluate Microbial Quality of Surface Water Sources Used for Irrigation

Location: Environmental Microbial & Food Safety Laboratory

Title: Water retention and preferential states of soil moisture in a cultivated vertisol

Author
item VANDERLINDEN, KAR - Ifapa Centro Alameda Del Obispo
item Pachepsky, Yakov
item PEDRERA-PARRILLA, AURA - Ifapa Centro Alameda Del Obispo
item MARTINEZ, GONZALO - Universidad De Cordoba
item ESPEJO-PEREZ, A - Universidad De Cordoba
item PEREA, F - Ifapa Centro Alameda Del Obispo
item GYRALDEZ, JUAN - Universidad De Cordoba

Submitted to: Soil Science Society of America Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/3/2016
Publication Date: 2/28/2017
Citation: Vanderlinden, K., Pachepsky, Y.A., Pedrera-Parrilla, A., Martinez, G., Espejo-Perez, A., Perea, F., Gyraldez, J.V. 2017. Water retention and preferential states of soil moisture in a cultivated vertisol. Soil Science Society of America Journal. 81(1):1-9.

Interpretive Summary: Vertisols are soils with a very high clay content commonly found in semiarid areas. One of the remarkable properties of those soils is a very fast transition from dry to wet state and back. Rarely are they in the intermediate water content state. We hypothesized that this feature may be related to water retention properties of those soils. We measured soil water retention with high detail and found that the soil in dry state has water mostly within clay particles, and soil in wet states has water contents outside soil aggregates. Results of this work can be useful in assessment and management of vertisois in that they provide a simple diagnostic method to assess expected water contents in wet and dry states, and also to predict how fast will the soil switch from wet to dry state and vice versa.

Technical Abstract: Vertisols are well suited for rainfed agriculture in water-limited environments as a result of their unique water transfer and retention characteristics. Despite their importance, the agro-hydrological behavior of these soils under seasonally dry climates is not yet fully understood. We provide a detailed description and analysis of regionalized water retention, T, data of a vertisol, from saturation to oven dryness, measured on 27 undisturbed topsoil (0-0.05 m) samples from an experimental field in southcentral Spain and relate this information to the occurrence of field-observed preferential soil moisture states. A continuous function was fitted to the retention data,consisting of the sum of a double exponential model and the Groenevelt and Grant model. An inflection point at pressure head, |h|= 1.1×10^5, T = 0.12 kg kg^-1, and an equivalent pore radius, d = 14 nm, was interpreted as the boundary between the inter- and intra-clay aggregate pore spaces, and corresponded with the transition from the intermediate to the dry field soil moisture state. The mode of the textural pore space (|h|= 7.3×10^3 cm, T = 0.21 kg kg^-1 , and d = 200 nm) matched the transition from the wet to the intermediate field soil moisture state. We related these characteristics of the SWRC with the spatio-temporal soil moisture dynamics and patterns observed in the field, characterized by fast transitions between preferential soil moisture states. The proposed framework is suitable for comparing effects of different soil management strategies on the agro-hydrological performance of vertisols.