Impact of Soil Micromorphological Features on Water Flow and Herbicide Transport in Soils

Abstract

A: WF, weighting factor. S S : V Z M The impact of varying soil micromorphology on soil hydraulic proper es and, consequently, on water fl ow and herbicide transport observed in the fi eld is demonstrated on three soil types. The micromorphological image of a humic horizon of Haplic Luvisol showed higher-order aggregates. The majority of detectable pores corresponding to the pressure head interval between −2 and −70 cm were highly connected, separa ng higher-order peds with small intrapores that possibly formed zones with immobile water. Herbicide was regularly distributed in this soil. The majority of detectable large capillary pores in a humic horizon of Greyic Phaeozem were separated and aff ected by clay coa ngs and fi llings. The herbicide transport in this soil was highly aff ected by preferen al fl ow. Macropores corresponding to pressure heads higher than −2 cm were detected in a humic horizon of Haplic Cambisol. However, preferen al fl ow only slightly infl uenced the herbicide transport in this soil. Single-porosity and either dual-porosity or dual-permeability fl ow and transport models in HYDRUS-1D were used to es mate the soil hydraulic parameters from laboratory mul step ou low and ponded infi ltra on experiments via numerical inversion and to simulate the herbicide transport experimentally studied in the fi eld. Appropriate models were selected on the basis of the soil micromorphological study.

Droplet infiltration dynamics and soil wettability related to soil organic matter of soil aggregate coatings and interiors

“…Aggregate coatings and biopore walls are characteristic soil structural features (e.g., Gerke and Köhne, 2002;Kodešová, 2009;Kodešová et al, 2011Kodešová et al, , 2015Rogasik et al, 2014) that are of great importance when attempting to describe preferential flow and transport processes in soils (e.g., Gerke, 2012;Kodešová, 2009;Kodešová et al, 2008Kodešová et al, , 2009Kodešová et al, , 2010Kodešová et al, , 2012. Clay-organic coatings often cover aggregates and biopores in the clay-illuviation Bt-horizons of Luvisols (IUSS Working Group WRB, 2014).…”

“…Kodešová et al (2012), are shown in Table 1. Kodešová (2009) ;Kodešová et al (2008Kodešová et al ( , 2009) reported intensively developed blocky, and large and long prismatic aggregates in the Bt1 and Bt2 horizons, respectively. Soil aggregates in the Bt1 and Bt2 horizons were covered by clay and organic matter coatings.…”

Soil micromorphology use for modeling of a non-equilibrium water and solute movement

“…The micromorphological analysis was also used to explain various soil water retention without the extending flow modeling by Constantini et al (2006), Juhász et al (2007) and Pires et al (2008). Kodešová et al (2008) investigated the impact of varying soil micromorphology on soil hydraulic properties and consequently on water flow and herbicide (chlorotoluron) transport observed in the field on three soil types (Haplic Luvisol, Greyic Phaeozem, Haplic Cambisol). The field experimental method was described in detail by Kočárek et al (2005).…”

“…However, Jarvis (2007) and Köhne et al (2009a) argued that macropores (pores causing the physical non-equilibrium of water flow close to saturation) are pores with an equivalent diameter larger than about 300-500 µm (corresponding to a pressure head of -10 and -6 cm), Kodešová at al. (2006Kodešová at al. ( , 2008Kodešová at al.…”

“…The same procedure was also applied for herbicide transport simulation by Kodešová et al (2008Kodešová et al ( , 2009). This paper is focused on a review of studies, which used soil micromorphology to improve estimation of parameters characterizing non-equilibrium water flow and solute transport in structured soils.…”