Cover crop interseeding effects on aboveground biomass and corn grain yield in western North Dakota

Authors: ANTOSH, ERIC - Natural Resources Conservation Service (NRCS, USDA); Liebig, Mark; Archer, David; LUCIANO, ROBERTO - Natural Resources Conservation Service (NRCS, USDA)

Submitted to: Crop, Forage & Turfgrass Management
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/5/2022
Publication Date: 2/17/2022
Citation: Antosh, E., Liebig, M.A., Archer, D.W., Luciano, R. 2022. Cover crop interseeding effects on aboveground biomass and corn grain yield in western North Dakota. Crop, Forage & Turfgrass Management. 8:e20148. https://doi.org/10.1002/cft2.20148.
DOI: https://doi.org/10.1002/cft2.20148

Interpretive Summary: Cover crops can provide many benefits, but the short growing season and variable weather in the northern Great Plains makes it difficult to include them in cropping systems. Relay intercropping - planting cover crops into standing grain crops - could be a way to successfully grow cover crops in this region. This approach has been used in wetter areas of North Dakota, but it has not been tested in the western part of the state where conditions are typically drier. A 3-year study was conducted on the Area 4 SCD Cooperative Research Farm near Mandan, ND to find out the best time to intercrop cover crops in corn. Study treatments included a no cover crop control and cover crops planted at advancing corn growth stages (1st planting = V4, 2nd planting = V6, 3rd planting = V8). Across years, aboveground biomass was greatest in the 1st planting (393 lb/ac), least in the control and 3rd planting (Mean = 212 lb/ac), and intermediate in the 2nd planting (247 lb/ac). Cover crop treatments had no significant effect on corn grain yield in any year, suggesting that intercropping cover crops in corn will not reduce corn yield under conditions like those observed in this study. Limited competition from cover crops and weeds likely contributed to this outcome, as cover crop production was low. Future intercropping research in western North Dakota should consider the forage value of the cover crops, winter survival of different cover crops, and row spacing effects on biomass production and crop yield.

Technical Abstract: Including cover crops in established crop rotations can enhance the delivery of ecosystem services from agricultural lands. Inclusion of cover crops in rainfed cropping systems in the northern Great Plains, however, is challenging due to the short growing season, limited precipitation, and variable weather conditions. Intercropping cover crops in established row crops has been proposed as one approach to address these challenges. A 3-yr study was conducted near Mandan, ND to evaluate the effects of intercropping planting time on cover crop and weed aboveground biomass and subsequent corn grain yield. Treatments included a no cover crop control and cover crops planted at advancing corn vegetative growth stages (1st planting = V4, 2nd planting = V6, 3rd planting = V8), replicated 4-6 times each year. Across years, aboveground biomass was greatest in the 1st planting (440 kg/ha), least in the control and 3rd planting (Mean = 237 kg/ha), and intermediate in the 2nd planting (277 kg/ha) (P<0.0001). Corn grain yield did not differ among treatments within or across years, with mean grain yields of 4.2, 7.3, and 4.0 Mg/ha in 2018, 2019, and 2020, respectively. The absence of a grain yield effect suggested intercropping cover crops in corn will not negatively impact crop production in the same year under conditions similar to those observed in this study. Limited competition from cover crops and weeds likely contributed to this outcome, as aboveground biomass production was low. Future intercropping research in western North Dakota should consider the forage value of aboveground biomass, winter survival of different cover crops, and row spacing effects on biomass production and crop yield.