Does cover crop grazing damage soils and reduce crop yields?

Authors

Humberto Blanco-Canqui, University of Nebraska - LincolnFollow
Mary E. Drewnoski, University of Nebraska, LincolnFollow
Jim C. MacDonald, University of Nebraska - LincolnFollow
Daren Redfearn, University of Nebraska-LincolnFollow
Jay Parsons, Univeresity of Nebraska-LincolnFollow
Gary W. Lesoing, Southeast Research & Extension Center, Auburn
Tyler Williams, Metro Extension District, Lincoln

ORCID IDs

https://orcid.org/0000-0002-9286-8194

Date of this Version

2020

Citation

Agrosyst Geosci Environ. 2020;3:e20102. 1 of 11

https://doi.org/10.1002/agg2.20102

Comments

2020 The Authors.

Abstract

Cover crop (CC) grazing can be a potential strategy to support livestock and crop production while enhancing soil ecosystem services, but research on this potential multi-functionality of CCs is limited. We assessed 3-yr cereal rye (Secale cereale L.) CC grazing impacts on soil compaction, structure, water infiltration, fertility, and crop yields on an on-farm irrigated strip-till continuous corn (Zea mays L.) silage experiment on a sandy loam with <1% slope in west-central Nebraska. Treatments were: (a) non-grazed CC, (b) grazed CC, and (c) no CC. Across the 3 yr, cattle grazed CCs at 5.9 AUM ha−1 with grazing occurring over a 4-mo period during winter and/or spring, depending on the year. We measured soil properties within 5 d after grazing ended in spring before tilling and plant- ing corn. Cattle grazing resulted in a 92% decrease of CC biomass, compared with non-grazed CCs. Grazing did not affect soil penetration resistance (com- paction parameter), bulk density, aggregate stability, pH, and concentration of organic matter and nutrients except in the 2nd yr where it reduced cumulative infiltration by 80% and increased penetration resistance from 1.23 to 1.72 MPa but such increase was below root growth thresholds (<2 MPa). Cover crop grazing had no negative effect on corn silage yields although data were variable. Overall, CC grazing for 3 yr had small and variable effects on soils and crop yields, indi- cating that it can be a management option to support livestock production but more long-term data from different tillage and cropping systems, and climates are needed to further understand CC grazing implications.