Although the magnitude of yield losses from N deficiency cannot be predicted from protein concentrations, there are many practical applications of this study. In addition, growers who have not recently had their soil analyzed may be more inclined to do so in their fields which produce low protein wheat. For each curve, fertilizer N rates increase in the direction of the arrows. Figure 2 . Relative yield versus grain protein for spring wheat.
Dark circles indicate yield significantly below maximum.
Light circles indicate yield was not reduced by N deficiency or excess .