WHY TEST

End of season stalk testing was developed to evaluate how well nitrogen fertilizer was utilized by the corn plant. This allows the producer to distinguish between over fertilization and fertilizing to maximize profits.

BASIS FOR TEST

A relationship between stalk nitrate concentrations and relative yields was developed from trials having rates of N fertilizer applied ranging from 0 to 300 lb. N/acre.

Corn plants with inadequate available nitrogen remove N from lower cornstalks and leaves during the grain filling period.

Corn plants with excess N for maximum yields accumulate nitrate in their lower stalks at the end of the season.

This relationship indicates that stalk N concentration can be divided into four categories for interpretation.