Abstract The low adoption of annual cover crops in the United States Corn Belt has motivated research into novel cover cropping systems that mitigate the degrading of water quality due to soil and nutrient loss without compromising corn ( Zea mays L.) yield. This 3‐year field study compared a Kentucky bluegrass ( Poa pratensis L.) as a perennial groundcover (PGC), two interseeded annual cover crop systems (standard and wide‐row), and a no‐cover control for their effects on corn yield and subsurface drainage water quality. Each plot was monitored weekly for subsurface drainage flow and nutrient losses using a randomized complete block design with three replicates. The study occurred during a period of below‐average precipitation, which caused strong year‐to‐year and seasonal variations in treatment performance. Treatment effects were most evident in the study's wettest year, when increased rainfall following a dry season caused a summer nitrate flush. During this high‐leaching summer period, all cover crop systems reduced nitrate concentrations compared to the control. When averaged across the entire study, the high‐biomass wide‐row interseeded system reduced flow‐weighted NO 3 ‐N concentrations by 22% but reduced grain yield 20%. In contrast, the PGC system reduced NO 3 ‐N by 20% with no associated grain yield loss. These findings highlight a critical yield trade‐off for wide‐row annual cover cropping systems and suggest that perennial systems like Kentucky bluegrass PGC are a promising strategy for mitigating early summer nitrate losses.
Myers‐Bailey et al. (Sun,) studied this question.