Ohio State University farmdoc daily (11):90 farmdoc daily (11):90, Department of Agricultural and Consumer Economics, University of Illinois at Urbana-Champaign, June 8, 2021. Permalink Over time, per acre input costs on grain farms tend to rise with commodity price increases (see also farmdoc daily, September 17, 2015). In this article, we illustrate this relationship for corn in 1) central Illinois using data from Illinois Farm Business Farm Management (FBFM) and 2) the U.S. using data from the Economic Research Service (ERS). Given current higher commodity prices, historical relationships suggest rising input costs for the 2022 crop. Sometime in the future, commodity prices will decline. When this occurs, history suggests that input costs will not decline as much as the commodity price decline.