Water retention curve to analyze soil structure changes due to liming

Abstract

Liming can influence crop growth by altering pore geometry, pore size distribution and water retention characteristics in acid soils. The aim of this work is to determine liming effects on the soil structure based on analysis of water retention data using a cubic spline adjustment function. For that, the authors investigated the effect of three lime rates (0, 15 and 20 t ha-1) on soil water retention characteristics and pore size distribution of a silty-clay "Cambissolo Háplico Alumínico" (Dystrudept) located in the Se region of the Paraná State, Brazil. Soil cores were collected after 31 months of the experiment at 0-10 cm and 10-20 cm soil layers. eleven matric potentials (from 0 to-7000 cm H2O) were employed to calculate soil water retention and pore size distribution curves. The pore size distribution curves revealed trimodal soil porosity with three distinct peaks. equivalent pore diameters ranging from 9.18 µm to 13.18 µm separated structural and matrix domains. Small differences exist in the pore size distribution curves due to liming and between layers for all peaks. With no-till plus surface liming, the volume of large pores diminished at the two layers and the volume of small pores increased at the surface layer.

Impacto do manejo do solo nas propriedades físicas de um latossolo vermelho da região de ‘Campos de Cima da Serra’, Rio Grande do Sul

“…Soil microporosity is linked to the water retention capacity; soils that present a higher number of micropores tend to retain more water. The micropores also improve the overall water infiltration capacity by acting as capillary conductors for the water to flow through the soil profile [17].…”

Beware of scaling artefacts and implicit model characteristics when fitting soil water release and moisture capacity data

“…The cumulative and frequency distributions of pore size can be used to "quantify" soil physical quality or health, as well as assess soil quality/health responses to changes in land management. For example, Reynolds et al (2009) used a range of soil types and land managements to propose representative pore size frequency distributions and water release curves for soils with good physical quality; Ferreira et al (2019) used changes in pore size frequency distribution to elucidate soil physio-hydraulic responses to agricultural liming; and Jensen et al (2020) used both cumulative and frequency pore size distributions to assess the soil physical impacts of converting long-term grassland to annual arable cropping and vice versa.…”

“…Ghanbarian and Skaggs 2022) may lead to fictitious or physically unrealistic results. Similarly, use of log-transformed moisture capacity curves (−dθ /d log b h vs. log b h) may yield distorted pore size distributions, and potentially inaccurate (or fictitious) modal, index and optimal pore sizes (e.g.,Dexter and Richard 2009;Dexter et al 2008;Sillers et al 2001;Ferreira et al 2019;Jensen et al 2020;Ghanbarian and Skaggs 2022).…”