Nitrogen content of pea-based cover crop mixtures and subsequent organic corn yield
Lavergne, S., Vanasse, A., Thivierge, M.N., Halde, C. (2021). Nitrogen content of pea-based cover crop mixtures and subsequent organic corn yield. Agronomy Journal, [online] 113(4), 3532-3547. http://dx.doi.org/10.1002/agj2.20727
Plain language summary
Agricultural producers with organic certification do not have access to synthetic nitrogen fertilizers to meet the nitrogen needs of corn. In addition to using farmyard manures, many are turning to cover crops. The objective of this experiment was to verify the effect of fall-seeded cover crops on subsequent corn yield, with or without the application of pelletized poultry manure. At three sites in Quebec, Canada, a pure stand of field pea was compared to pea-based mixtures with 2, 6 and 12 species in total. Corn yield increased by 10% with poultry manure, irrespective of the cover crop treatment. Pea-based fall-seeded cover crops increased corn yield by an average of 28% compared to a control with no cover crop. Because field pea represented an important proportion of the mixtures, there was no clear advantage of using mixtures instead of a pure stand of field pea with respect to nitrogen supply and corn yield. These results indicate that the use of cover crops, either a pure legume or legume in mixture, could contribute to organic grain corn yield in Quebec.
Organic growers rely heavily on manure additions to meet corn (Zea mays L.) nitrogen (N) needs. Considering the limited availability of farmyard manure and its increasing cost, the use of cover crop mixtures may help in addressing this challenge. The impact of fall-seeded cover crops with or without pelletized poultry manure application on corn yield and N dynamics was investigated at three sites in Québec, Canada. Cover crop treatments consisted of field pea (Pisum sativum L.) in a pure stand, 2-, 6-, and 12-species pea-based mixtures, and a weedy control without cover crops. Nitrogen content of shoot biomass was the greatest for the pure stand of field pea at Augustin17 (157 kg N ha–1), and for the pure stand of field pea and the 2-species mixture at Augustin18 (average of 109 kg N ha–1) and Barthelemy17 (average of 171 kg N ha–1). Nitrogen content of root biomass averaged 13 kg N ha–1. Cover crops increased organic corn grain yield by 28% compared to a weedy control. Corn grain yield was similar following the pure stand of field pea and the mixtures of 2 and 12 species, showing no clear advantage of using mixtures instead of a pure stand of field pea regarding N supply and corn yield. Corn yield increased by 10% with poultry manure application irrespective of the cover crop treatments. These results indicate that the use of cover crops, either a pure legume or legume in mixture, could contribute to organic grain corn yield.