Monday, November 13, 2006

Corn Response to Compost and Manure Amendments Combined with No-Tillage or Plow Till.

Jeanne Durkalski, Ping Wang, Harry Hoitink, and Warren Dick. Ohio State Univ, 1680 Madison Ave, Wooster, OH 44691

Livestock producers in the United States are increasingly aware of environmental issues associated with production, storage, treatment and utilization of animal wastes. It is well known that fresh and composted manure can be effectively used to sustain corn production. Rarely studied, however, is the conversion from mineral to more organic based systems of nutrients under contrasting tillage systems. We conducted a field study where uncomposted and composted cow (Bos taurus) manures were applied at three different ‘loading’ rates of 28, 56, and 112 dry Mg ha-1 in the first year, followed by three years of maintenance rates of 11 Mg ha-1. Amendments were applied in the autumn to a clay loam Hoytville (H) soil and in the spring to a silt loam Wooster (W) soil and either immediately plowed down (PT) or left on the surface as part of the no-tillage (NT) treatment. Controls consisted of a no-amendment treatment and a mineral fertilizer only treatment. Stand counts and grain yields were recorded and soil cores analyzed after three (W) or four years (H) years of treatments. Planting immediately after fresh manure application lowered stand counts and grain yields when NT was used. Delaying planting by a month, or manure incorporation or composting reversed the detrimental effects of fresh manure on seedling emergence. Lower stand counts did not always result in lower yields, especially on NT plots. Carbon and other plant nutrient (N, P, K) concentrations were generally significantly greater for the surface soil layers of NT than PT, but the reverse was true at depth. We conclude that high loading rates of manure and composts, followed by annual maintenance rates, are effective in maintaining high corn grain yields. However, care must be taken to first compost the manure or to apply it with incorporation if seeding is immediately conducted.