Comparison among monitoring strategies to assess water flow dynamic and soil hydraulic properties in agricultural soils

Abstract

Irrigated agriculture is usually performed in semi-arid regions despite scarcity of water resources. Therefore, optimal irrigation management by monitoring the soil is essential, and assessing soil hydraulic properties and water flow dynamics is presented as a first measure. For this purpose, the control of volumetric water content, θ, and pressure head, h, is required. This study adopted two types of monitoring strategies in the same experimental plot to control θ and h in the vadose zone: i) non-automatic and more time-consuming; ii) automatic connected to a datalogger. Water flux was modelled with Hydrus-1D using the data collected from both acquisition strategies independently (3820 daily values for the automatic; less than 1000 for the non-automatic). Goodness-of-fit results reported a better adjustment in case of automatic sensors. Both model outputs adequately predicted the general trend of θ and h, but with slight differences in computed annual drainage (711 mm and 774 mm). Soil hydraulic properties were inversely estimated from both data acquisition systems. Major differences were obtained in the saturated volumetric water content, θs, and the n and α van Genuchten model shape parameters. Saturated hydraulic conductivity, Ks, shown lower variability with a coefficient of variation range from 0.13 to 0.24 for the soil layers defined. Soil hydraulic properties were better assessed through automatic data acquisition as data variability was lower and accuracy was higher.

Environmental Scanning Electron Microscopy Application for Brackish Water Irrigation Impact on Soil

“…Clay mineral content (illite) in Layer 1 accounted for up to 9.7% and was practically absent in Layer 2 (Table 2). Detailed site descriptions can be found in previous studies (Valdes‐Abellan et al, 2015, 2017).…”

“…The 40-cm depth assured the absence of root activity and the avoidance of other factors that affect hydrophilicity, such as the production of organic matter by roots. The soil water model has been described (Valdes-Abellan et al, 2015). Conservative solute transport was previously done, and results are presented in Valdes-Abellan et al (2014).…”

Reactive transport modelling to infer changes in soil hydraulic properties induced by non-conventional water irrigation

“…The soil pressure head has been controlled only at depths of 20 and 60 cm. A detailed description of the experimental plot and installed devices can be found in Valdes-Abellan et al (2015).…”

“…A 30 years numerical simulation with HP1 has been performed to predict the geochemically-induced (mineral kinetics) long-term changes in soil physical and hydraulic properties. A calibrated/validated water flow model from soil water content and pressure head observations along three years is used as initial soil parameterization (Table 1) (Valdes-Abellan et al, 2015). At the top, atmospheric boundary condition (potential evapotranspiration, water input and root water uptake) are considered, while free drainage is assumed as the lower boundary condition since water table is far below the domain.…”

Traffic effects on soil compaction and sugar beet (Beta vulgaris L.) taproot quality parameters

“…Soil compaction is defined as "the process by which the soil grains are rearranged to decrease void space and bring them into closer contact with one another, thereby increasing the bulk density" (Kroulík et al, 2011). Soil compaction leads to negative consequences such as the reduction of soil porosity, decrease of aeration (McHugh et al, 2009), reduction of saturated hydraulic conductivity and an increase in soil resistance to roots exploration (Balbuena et al, 2003;Valdes-Abellan et al, 2015). Some different approaches have been recently proposed in the last year for fast characterisation of soil condition, mainly consisting of sensors mounted on tines or discs allowing on the go data collection (Chukuw & Bowers, 2005;Hemmat et al, 2008;.…”