SPATIALLY PROBABILISTIC EVALUATION OF THE BENEFIT OF STARTER FERTILIZER TO NO-TILL CORN

摘要

There is no information relating a crop's response to starter fertilizer to landscape factors. There is evidence that yield patterns in a field under uniform management will be related to soil properties and topography. The objectives of this study were to evaluate corn's response to starter fertilizer as a function of soil properties and landscape position, to partition that response into population and growth components, and to determine the spatial probability of an economic response to starter fertilizer. Areas were selected within two fields and alternating passes of the planter "with" and "without" starter fertilizer, applied at a rate to give 14.5 kg N and 5.7 kg P/ha, were made. In 1999, the fields studied exhibited similar driving characteristics (elevation, slope, and clay content) in their spatial distribution of corn yields, both with and without starter fertilization. Yield and population responses to starter fertilizer application did not follow the same spatial pattern in the studiedfields, even though soils, and soil and crop management practices, were the same. The yield response to starter fertilizer in Field 1 was generally positive, and above the economic threshold. However, in Field 2, the yield response to starter fertilizerwas generally negative to neutral, and below the economic threshold. There was little spatial pattern to the probability of an economic response to starter in either field, at least in part due to the droughty corn production season.