Yield Response of Corn to Single and Combined Application of Cattle Manure and Urea

A 2-year field experiment was conducted to evaluate the single- and combined-application effects of cattle manure and urea on corn (Zea mays L.) production. A randomized complete block design was conducted with five nitrogen (N) rates (36, 72, 108, 144, and 180 kg N ha-1) as urea, cattle manure, or both. The stover yield and aboveground biomass increased with urea application up to 144 kg N ha-1 but remained unchanged at greater N rates. At all N rates, combined application of manure and urea resulted in greater grain yields than single applications. Crop response to applied N was greater in the combined N application system than in the single-application treatments. The greatest grain yield was found in plots that had received a combination of 18 ton manure ha-1 plus 160 kg urea ha-1. Manure application along with urea enhanced crop yield response to urea and reduced its application rate.