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Manure application to the soil surface may not be as effective as incorporated manure for crop production, because of potential N loss. An experiment was conducted to determine the effects of composted (compost) and noncomposted manure from beef cattle ( Bos taurus ) feedlots on corn ( Zea mays L.) yield and N uptake under two tillage systems in 4 years. Conventional and no‐till systems were used as main plots, and subplots consisted of application of composted and noncomposted manure and fertilizer to provide for corn N requirements, and check treatments. Manure and compost were applied and immediately incorporated by disking in the conventional system and left on the surface in the no‐till. Fertilizer was incorporated in the conventional system 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 treatment in all years except for no‐till in 1996. First‐year N availability was approximately 38% for manure and 20% for compost in both tillage systems. Apparent N use efficiency was 17% for manure, 12% for compost, and 45% for the fertilizer treatment across 4 years. Chlorophyll meter readings, indicating relative plant N concentration at different stages of growth, were closely related to N uptake and grain yield in years with adequate water supply, but not in the drier year of 1995. Stalk NO − 3 –N concentration at harvest was 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. Stalk NO − 3 –N concentration did not exceed the critical level for any treatment in other years. When the correct N availability factor is used, beef cattle feedlot manure and compost can be effectively utilized in no‐till corn production systems.
Eghball et al. (Wed,) studied this question.