Agroecosystem services from cover crop mixtures are linked to aboveground biomass and total N content (kg ha–1). Reported values in the literature, however, vary for aboveground biomass and total N content of cover crop mixtures compared with monocultures. We conducted a meta-analysis using results from 55 site-years from 21 studies conducted in the United States to examine biomass and N content of hairy vetch (Vicia villosa Roth)–cereal rye (Secale cereale L.) mixtures compared with respective monocultures. Overall, hairy vetch–cereal rye mixtures produced 63 and 21% more biomass compared with hairy vetch and cereal rye monocultures, respectively. The N content of hairy vetch–cereal rye mixtures was 150% greater than that of cereal rye monocultures. When the proportion of hairy vetch seeds (by weight) exceeded 46% of the mixture, the mixtures accumulated equivalent or more N than the greatest yielding monocultures (usually hairy vetch). Compared with monocultures, a more consistent positive response of mixtures on biomass and N content was found on coarse-textured soils and following corn (Zea mays L.) rather than soybean [Glycine max (L.) Merr.] harvest. With increasing growing degree days (GDD), the biomass and N content of mixtures decreased relative to hairy vetch monocultures but increased relative to cereal rye monocultures, suggesting better performance of hairy vetch at higher GDD. We conclude that hairy vetch–cereal rye mixtures can produce equivalent or more biomass than both monocultures and accumulate as much N as hairy vetch, and that the relative productivity of mixtures depends on soil type, previous crop, seeding proportion, and GDD.
|Number of pages||12|
|State||Published - Jul 1 2018|
Bibliographical noteFunding Information:
Our sincere thanks go to authors of all the studies included in this meta-analysis. We are grateful to the associate editor and three anonymous reviewers for their valuable comments that improved our manuscript. Funding support for the first (Resham Thapa) and fourth (Victoria J. Ackroyd) authors is provided through the USDA National Resources Conservation Services, Conservation Innovation Grant (CIG) no. 8042-21660-004-36-R and Agriculture and Food Research Initiative (AFRI) Competitive Grant no. 2016-67012-24711, respectively. The first author is also grateful to Northeast Sustainable Agriculture Research and Education (SARE) graduate student grant (Award no. GNE17-160-31064).
© 2018 by the American Society of Agronomy.
ASJC Scopus subject areas
- Agronomy and Crop Science