Does no-till cover crop influence in situ measured soil water potential and saturated hydraulic conductivity?

Abstract

Soil water energy determines soil water balance, plant water uptake, and soil thermal properties, but the effects of cover crops (CCs) on in situ measured soil water energy and temperature are not well understood. This study investigated how CCs affect in situ measured soil water potential (SWP), temperature, and saturated hydraulic conductivity (Kfs) during 2 years, with the hypothesis that CC-induced water transpiration can lower SWP. The CCs used included crimson clover (Trifolium incarnatum L.), winter wheat (Triticum aestavum L.), hairy vetch (Vicia villosa), oats (Avena sativa), triticale (Titicale haxaploide Lart.), barley (Hordeum vulgare L.), flax (Linum usitatissimum L.), and winter peas (Lathyrus hirsutus L.). Soil water potential and temperature sensors were installed at 0-10, 10-20, and 20-30 cm depths. Additionally, Kfs was measured in situ using a Guelph permeameter. Results showed that actively growing CCs can lower SWP, leading to increased water transpiration from the field compared with no cover crop (NC) management. Also, by lowering soil temperature, CCs can increase evapotranspirational efficiency compared to NC management. Further, by increasing evapotranspirational efficiency, CC, management resulted in increased subsurface water infiltration and storage as shown by higher Kfs values compared to NC management. In general, CCs have the potential to reduce SWP and temperature during their growth stages and this can be beneficial to seed germination and microbial activities.

Keywords

• precipitation
• quasi-steady infiltration rate
• soil organic carbon
• soil temperature
• sorptivity
• turgor pressure