Researchers at the University of Wisconsin-River Falls have developed a tool that rates the profitability of fertilization on pastures and grass-hay fields. The spreadsheet allows you to input current cost for hay and fertilizer, along with where you live, and then calculate the estimated returns. To access the spreadsheet, go to www.uwrf.edu/grazing/Pasture%20Nitrogen%20Fertilizer%20Profit%20Calculator.xls.