Interseeded cover crops did not cause corn yield loss in eastern North Dakota

Abstract

North Dakota is a transitional semiarid region with annual precipitation in the eastern part of the state of about 50–55 cm, mostly from rainfall. The moisture demand from interseeding cover crops into standing corn (Zea mays) early in the season has been a concern and is likely why most corn growers do not interseed cover crops. Corn grain yield was determined in response to interseeding of cereal rye (Secale cereale) or oat (Avena sativa), radish (Raphanus sativus), and camelina (Camelina sativa) and incremental fertilizer nitrogen (N) application rates for five site-years in the eastern North Dakota. Fifty-eight days and 35 days of leaf wetness from dew in 2019 and 2020, respectively, were recorded. Cumulative dew accumulation since cover crop emergence was 5.6 mm and 3.5 mm in 2019 and 2020, respectively. Interseeding and its interactions with fertilizer-N rate did not influence the grain yield. However, cereal rye produced the most biomass of the cover crop species, but the amount varied with site and growing season conditions. Late October, cereal rye biomass produced was 98.8 kg ha−1 in 2018, 352 kg ha−1 in 2019, and 70.3 kg ha−1 in 2020 at the Gardner site. Interseeding did not reduce grain yield loss compared to control. Outcomes will encourage corn growers to adopt cover crops without any changes in their fertilizer N application.