Abstract Conventional agriculture in the US Midwest has accelerated crop productivity but also contributed to undesirable environmental issues. Perennial groundcovers (PGCs), such as cool‐season grasses intercropped in the maize ( Zea mays L.) interrow, have the potential to reduce soil erosion rates and mitigate nutrient losses. However, work is still needed to select compatible PGC grasses to optimize the maize–PGC intercropping system. Our study assessed the compatibility of two grass species: Kentucky bluegrass (KBG; Poa pratensis L.; represented by three cultivars and one cultivar blend) and the summer‐dormant bulbous bluegrass (BBG; P. bulbosa L.). We compared the effect of these PGCs on grain yield and three soil resources (soil water, plant‐available nitrogen PAN, plant‐available phosphorus PAP) to that of the Control (no PGC). There were no differences in grain yield among the four KBG cultivars, so we focused on comparing the KBG, BBG, and Control. Both PGC species reduced PAN by 40%–50%, but only BBG reduced PAP by 19%, compared to the Control. KBG decreased maize yields by 28%–36% on average compared to the Control, and we surmised that lack of soil moisture was the major reason for this. For every 13 mm loss in soil water storage caused by PGC, there was a 1 Mg ha −1 loss in maize yield. The BBG treatment, however, showed little change in soil moisture and no decrease in grain yield relative to the Control. Our study shows that BBG can protect soil during winter yet has no negative effect on soil moisture and maize yield.
Galland et al. (Sun,) studied this question.