Hairy vetch is a fast growing winter annual legume but does not survive winter in most of Canada which makes it useful as a cover crop. Pulse legumes are mostly used as rotation crops but can also be used as cover crops. Soybean is a very good green manure before potatoes especially in warm climates. It is more tolerant of soil acidity than most legumes and is good against scab. A disadvantage of soybean grown as a crop is that it produces little residue and so does not contributes to the maintenance of soil organic matter levels.
Lupine is a favorite in Eastern European countries as a cover crop preceding potatoes.
Its effect on yields typically lasts for two years in the rotation. However, few lupine varieties are adapted to Northeastern North America. Beans have an inhibiting effect against nematodes and rhizoctonia and could be an interesting choice under our conditions. The advantage of the cereal nurse crop approach is that a harvestable crop can be secured. The legume develops fully after the cereal harvest.