The most consistent and positive yield increases have been reported in our neighboring states of Michigan and Minnesota. Research in both of these states has consistently measured grain yield increases from narrow rows in the 7 to 10 percent range. This would imply that perhaps the best opportunity for economic returns to using narrow corn row spacings is in regions with shorter growing season environments. Narrow row corn research results from around Wisconsin are presented in Table 1. At each location, corn was planted in 30 inch rows and either 15 or 20 inch rows.
All trials represent data from replicated field trials.
At ten of the twelve Wisconsin site-years there was a positive response to narrow row spacings. Both negative responses occurred in Manitowoc County. Across all locations, a 3.6 percent yield increase was measured. When sifting through the narrow row information, keep in mind that costs must be weighed against potential yield benefits. For some, modifying existing corn planters and combine heads may be done without a large capital outlay.