Spring application is best for conserving nutrients. Manure applied during the spring will release nutrients through mineralization during the growing season of most crops. Summer application is also acceptable and is most suited to hay and pasture areas rather than row crop or small grains. Application equipment such as tank wagons and injectors cannot be used on row crops or small grains during most of the growing season. Irrigation equipment such as traveling guns or center pivots can generally be used during the growing season of row crops and small grains.
Legumes can use manure nitrogen.
However, experience has shown that applying manure to legumes tends to stimulate broadleaf weed and grass growth in legume stands. Grasses such as fescue or reed canarygrass, which can use high rates of nitrogen application while tolerating relatively wet soil conditions, are excellent choices for manure utilization areas. Grasses or pasture also generally offer the greatest flexibility in terms of crop scheduling and land application operations. Applying manure in the fall generally results in greater nutrient loss than does spring application, especially if the manure is not incorporated. If the manure is incorporated and soil temperatures are below 50 degrees Fahrenheit, some of the nutrients will be immobilized and tend to remain in the soil until the following spring.