In situ water infiltration: Influence of cover crops after growth termination

Cover crops (CCs) are known to influence water infiltration just prior to termination, but their effects on water infiltration over time are less known. This study investigated the influence of CCs on in situ water infiltration just prior to CC termination (during April) and again 2 mo after CC termination (during June). The multi-species mixture of CCs used included hairy vetch (Vicia villosa Roth.), crimson clover (Trifolium incarnatum L.), winter wheat (Triticum aestivum L.), winter peas (Lathyrus hirsutus L.), oats (Avena sativa L.), triticale (Triticale hexaploide Lart.), barley (Hordeum vulgare L.), and flax (Linum usitatissimum L.). Infiltration rates were measured using double-ring infiltrometers during April and June. The physically based Parlange and Green-Ampt models were fitted to measured infiltration data. Cumulative infiltration was 52% higher in April and 68% higher in June under CC compared with no cover crop (NC) management. During April, the Parlange model-estimated saturated hydraulic conductivity parameter (K-dr) was 245% higher under CC compared with NC management. During the same sample period, the Green-Ampt-estimated K-dr parameter was 383% higher under CC compared with NC management. The higher sorptivity parameter and lower antecedent water content under CC compared with NC management during both measurement periods suggest that CCs can significantly improve water infiltration into the soil, and this effect can last for up to 2 mo after CC termination.