Note that manure characteristics vary significantly among species, so choosing a rate based on the coverage it provides on the soil surface is not a recommended method of determining an appropriate application rate.

There is widespread concern about potential sulfur (S) deficiencies in corn and soybeans in the North Central region. Sulfur is relatively immobile within the plant, so symptoms usually appear in the new growth. Atmospheric deposition used to supply a considerable amount of plant available S (about 8 to 15 pounds per acre annually), but with the implementation of the Clean Air Act, this amount has significantly decreased.