In greenhouse studies, overhead watering or subsurface irrigating soil can cause fluctuating moisture content, as can treatments such as surface application of residue used in cover crop research. This paper introduces a method of capillary mat subirrigation that maintained soil moisture at about field capacity for 16 d while no moisture could be detected after 6 d in soil placed under similar conditions that was not irrigated. In another study, subirrigation eliminated differences in soil moisture due to the presence of surface-applied residue and moisture supplied by hand watering from overhead was apparently removed from subirrigated treatments, which never differed in soil moisture content.
