Composted and noncomposted manure application to conventional and no-tillage systems: Corn yield and nitrogen uptake

Manure application to the soil surface may not be as effective as incorpora ted manure for crop production, because of potential N loss. An experiment was conducted to determine the effects of composted (compost) and noncompos ted manure from beef cattle (Bos taurus) feedlots on corn (Zea mays L.) yie ld and N uptake under two tillage systems in 4 years. Conventional and no-t ill systems were used as main plots, and subplots consisted of application of composted and noncomposted manure and fertilizer to provide for corn N r equirements, and check treatments. Manure and compost were applied and imme diately incorporated by disking in the conventional system and left on the surface in the no-till. Fertilizer was incorporated in the conventional sys tem and surface-applied in the no-till system each spring prior to planting . Results showed that in 3 out of 4 years there was no effect of tillage on corn grain yields of plots receiving manure or compost. Manure and compost application resulted in similar grain yield as that for fertilizer treatme nt in all Sears except for no-till in 1996. First-year N availability was a pproximately 38% for manure and 20% for compost in both tillage systems. Ap parent N use efficiency was 17% for manure, 12% for compost, and 45% fur th e fertilizer treatment across 4 years. Chlorophyll meter readings, indicati ng relative plant N concentration at different stages of growth, were close ly related to N uptake and grain yield in gears with adequate water supply, but not in the drier year of 1995. Stalk NO3--N concentration at harvest w as above the critical level of 2000 mg kg(-1) for the fertilizer treatment in 1995 but was low (<200 mg kg(-1)) for manure and compost treatments. Sta lk NO3--N concentration did not exceed the critical level for any treatment in other Sears. When the correct N availability factor is used, beef cattl e feedlot manure and compost can be effectively utilized in no-till corn pr oduction systems.