Effects of Aporrectodea Caliginosa on Soil Hydraulic Properties and Solute Dispersivity

Abstract

Earthworms have historically been absent from dryland agricultural fields in eastern Colorado, but their invasion or purposeful introduction may affect water retention and plant nutrient availability in soil. The objective of this study was to determine the effect of Aporrectodea caliginosa on hydraulic properties and solute dispersivity in soil from eastern Colorado (Adena [Ustic Paleargid]–Colby [Aridic Ustorthents] complex) that was amended with biosolids. Columns of repacked soil (50 cm in depth) were incubated with or without A. caliginosa for a period of 16 wk, after which columns were divided into 15‐cm depth increments to determine soil–water retention curves and solute breakthrough curves (BTCs) under unsaturated and saturated conditions. Aporrectodea caliginosa and their burrows and casts altered soil water retention curves in the top 30 cm of the soil, where A. caliginosa were most active. Earthworms also affected BTCs within the top 30 cm of soil resulting in an approximately 35‐fold increase in solute dispersivity under saturated flow conditions and a 4‐ to 10‐fold increase with unsaturated flow conditions. Overall, A. caliginosa increased soil residual water content by 33 to 41% and altered soil physical properties so that water flow became more tortuous, solute dispersion increased under saturated and unsaturated conditions, and soil drained over a larger range of tensions. In conclusion, A. caliginosa has the potential to reduce upward losses of water, increase water retention, and increase dispersion of agricultural chemicals applied to the soil surface.

Aporrectodea caliginosa, a relevant earthworm species for a posteriori pesticide risk assessment: current knowledge and recommendations for culture and experimental design

“…A. caliginosa plays several key ecological roles such as nutrient cycling (e.g., increasing nitrogen flux and lowering the C/N ratio (Sandor and Schrader 2007 ; McDaniel et al 2013 ) and enhancing nutrient availability for plants and microorganisms (Sharpley and Syers 1976 ; Sharpley and Syers 1977 ). A. caliginosa can also increase microbial biomass (Svensson and Friberg 2007 ) and its relatively high burrowing activity can have a positive impact on water infiltration /discharge (Ernst et al 2009 ; McDaniel et al 2015 ) and on soil aeration (Francis and Fraser 1998 ). Nevertheless, Eisenia sp .…”

Density Effect of Eisenia sp. Epigeic Earthworms on the Hydraulic Conductivity of Sand Filters for Wastewater Treatment

“…mainly consists of the generation of horizontal burrows at depths ranging between 0 and 10 cm [15]. Endogenic earthworms also create horizontal burrows [52] similar to epigeic ones but at greater depth (between 10 and 30 cm), which also increases the dispersion and retention time of water inside the soil [53,54]. In addition, compared with their surface counterparts, their burrows are usually less connected to the surface, which limits good water infiltration and lessens the hydraulic conductivity in the substrate [13,55].…”

Effects of winter wheat and endogeic earthworms on soil physical and hydraulic properties

“…, showed that the endogeic species A. chlorotica increases the percentage of water-stable aggregates (%WSA) and water holding capacity (WHC) of soil whereas the anecic Lumbricus terrestris only increased %WSA. Of the few other existing studies that consider the impact of earthworms on soil water retention and storage, most report an increase in water retention in the presence of endogeic (mainly A. caliginosa) (Blanchart et al, 1999;McDaniel et al, 2015) and epigeic (Ernst et al 2009;Smagin and Prusak 2008) species or when endogeics are associated with anecic or epigeic species (Boyle et al, 1997;. The effect of endogeics on soil water retention could be due to their burrowing behaviour with greater bioturbation of the soil and aggregate formation resulting in a tortuous and complex burrow system that helps to hold water and ensure more flow into the surrounding soil matrix (Pérès et al, 1998;Weiler and Naef, 2003).…”

“…Therefore, the impact of earthworms on soil hydrology will usually be within the context of the presence of plant roots. However, most laboratory-based studies on the impacts of earthworms on soil hydrology are carried out in the absence of plants (Bastardie et al 2003;Capowiez et al 2015;Ernst et al 2009;McDaniel et al 2015). Plant roots penetrate the soil more slowly (at a rate of up to 0.025 m day −1 ) than earthworms (typical burrowing rates of 0.1 to 0.2 m day -1 Ruiz et al 2015).…”