Odor nuisance can be defined by four factors: frequency, duration, intensity and offensiveness. The frequency of land-application of manure is often low when farmers are following a nutrient management plan (NMP) since application typically occurs before planting or right after harvest.The duration may also be limited to the time it takes manure on the surface to dry, but the intensity (since many fields receive manure during an application cycle) and the offensiveness (coming from an untreated manure storage) can create quite a nuisance.