Northeast Research and Demonstration Farm
Oat is the major spring-sown small grain crop in Iowa. Spring-sown small grains can be used for grain and straw production, as a companion crop to establish hay and pastures, or as a source of early-season forage as hay or haylage. Because small grains generally mature before the end of July in Iowa, a forage legume, cover crop, or green manure crop can follow oats, or animal manure can be spread on the field in which oats were grown.
Iowa State University
Pecinovsky, Kenneth T. and Lang, Brian J., "Oat Variety Trial" (2011). Iowa State Research Farm Progress Reports. 234.