Trial Report Summary

The Effect of Grazing and Non-grazing of Annual Green Manures on Following Crops (Year 2)

Crop Type(s):
Oats, Peas
Centre(s):
PCDF
Year(s):
2020
Collaborators(s):

PCDF

Objective(s):

To evaluate the use of an annual green manure crop for grazing by livestock and to provide fertility for the following crop (2019); and to evaluate the performance of three annual field crops after a green manure crop, with and without grazing (2020).

Project Findings:

The current study established a green manure crop on May 14, 2019. Half of the green manure crop was swathed (to terminate the crop) and intensively grazed by sheep on August 19, and the other half was mowed. Both areas were disked in October, after a killing frost.

Background:

The use of green manure crops to provide nitrogen is well-understood in organic agriculture. One of the
barriers to adoption of green manures is that there is no “harvestable” product and no income from that
year. Research conducted by the Natural Systems Agriculture laboratory at the University of Manitoba
has demonstrated that grazing the green manure by livestock can kill the crop, providing an alternative
to terminating the crop with tillage. Further, grazing results in large amounts of available N in the soil.
Follow-up research by the Natural Systems Agriculture laboratory demonstrated that there was no
significant difference in the year-2 crop yield for grazed and ungrazed treatments. The results for that
research suggest that there is no yield decrease associated with grazing a green manure.

PDF:

Entire findings are available by downloading the report PDF.

Download PDF