Q.Cover Crops
What is the best cover crop for nitrogen fixation?
A.
Hairy vetch, crimson clover, Austrian winter peas, and field peas are the top nitrogen-fixing cover crops. Hairy vetch can fix 100-200 lbs N per acre over a winter season, the highest of common annual covers. Pair with a cereal grain (winter rye, oats) to add biomass and prevent vetch from getting weedy.
State crop calendar pages cover species-specific planting windows. Variety review pages cover cultivar selection.