ECONOMIC RATE ANALYSIS OF NITROGEN-FERTILIZATION IN WHEAT

The response of wheat (Triticum aestivum L.) to macroelement fertiliza tion was investigated on a large number of trials, with 195 short-stem varieties and 58 long-stem varieties. The results have shown that fer tilization rates exceeding 195 lb N/acre do not result in higher yield s. Economically optimum fertilizer rates were 158 lb N/acre for short- stem varieties and 139 lb N/acre for long-stem varieties. Analysis sho ws that the economic profit for a given yield curve is a function of t he ratio of fertilizer cost to the price of product. This ratio cannot be higher than 9.75 for short-stem wheat varieties or higher than 14. 5 for long-stem wheat varieties.