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Paraskevi A. Londra

-form analytical models describing soil hydraulic properties ( Brooks and Corey, 1964 ; van Genuchten, 1980 ). Unfortunately, in some cases, the calculated K ( θ ) values using the retention curve data and the saturated hydraulic conductivity may deviate

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Paraskevi A. Londra, Maria Psychoyou, and John D. Valiantzas

the relations of D ( θ ) and consequently K ( θ ). Therefore, the K ( θ ) values were compared with the values predicted by the most popular closed-form analytical hydraulic model of van Genuchten–Mualem. Furthermore, the K s was determined

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E. Carmona, J. Ordovás, M.T. Moreno, M. Avilés, M.T. Aguado, and M.C. Ortega

Static hydrological properties [aeration capacity, easily available water, reserve water, water release curves: θvm), and specific humidity curves] and dynamic hydrological properties (saturated and unsaturated hydraulic conductivity) of sub strates based on industrial cork residue (the bark of Quercus suber L.) and cork compost were studied. Samples of similar granulometry have been used to establish the effect of cork composting on the afore mentioned physical properties. Different models were tested to describe the mechanism of water release from these materials. Van Genuchtens model (Van Genuchten, 1978) was the best fit and produced specific humidity curves that revealed slight differences in the ratio of water capacity function. When cork residues were composted for 7 months, important changes occurred in hydrological properties of the material as it became more wettable. Water retention significantly increased from 45% to 54%, at a potential of 5 kPa, although this did not necessarily result in increased water available to plants. A study of the unsaturated hydraulic conductivity (Kunsat) of these materials revealed a significant de crease in the Kunsat water potential at 0-5 kPa, which corresponds to the range in which the irrigation with these substrates was usually carried out. The long composting process resulted in increased Kunsat between 4 and 5 times that of uncomposted material, which would improve the water supply to the plant.

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James E. Altland, James S. Owen Jr, and William C. Fonteno

accurately describes the relationship. Numerous models have been proposed to describe MCCs ( Brooks and Corey, 1966 ; King, 1965 ). van Genuchten (1980) proposed the following model for describing soil water content ( θ ) as a function of pressure (h

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Patrice Cannavo, Houda Hafdhi, and Jean-Charles Michel

the fluxes calculated previously with the hydraulic gradient ( dψ ) at the same positions ( dz = h 1 –h 2 ) and times: Data treatment Water retention modeling. Water retention data were modeled using the van Genuchten (1980) model: where ψ is the

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Jeb S. Fields, William C. Fonteno, Brian E. Jackson, Joshua L. Heitman, and James S. Owen Jr.

-parameter nonlinear model was introduced, which is able to more accurately predict relationships between volumetric water content (Θ) and water potential (Y) than previous models ( Van Genuchten and Nielsen, 1985 ). The five-parameter Van Genuchten model ( Van

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George Gizas, Ioannis Tsirogiannis, Maria Bakea, Nikolaos Mantzos, and Dimitrios Savvas

level and the corresponding best fit curves. The latter were established by using a model proposed by Van Genuchten (1980) and Van Genuchten and Nielsen (1985) for soils and adapted to horticultural substrates by Milks et al. (1989) : where h is

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Kevin J. McInnes and James C. Thomas

had been watered to excess of holding capacity and allowed to drain for 24 h after being covered with a plastic wrap to minimize evaporation ( Fig. 2 ). The model of van Genuchten (1980) was fit to the water content–water tension data and then the

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Lucas O’Meara, Matthew R. Chappell, and Marc W. van Iersel

less than 0.38 m 3 ·m −3 ). For more details on this technique, see Peters and Durner (2008a , 2008b ). The Hyprop software was also used to fit a bimodal van Genuchten curve to the MRC curve ( Durner, 1994 ). The bimodal van Genuchten curve is the

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Rangjian Qiu, Yuanshu Jing, Chunwei Liu, Zaiqiang Yang, and Zhenchang Wang

( Capsicum annuum L.) are considered moderately sensitive to salt stress ( Rameshwaran et al., 2016 ). The threshold-slope linear response model ( Maas and Hoffman, 1977 ) and the sigmoidal-sharp salinity response model ( Van Genuchten and Hoffman, 1984