NITRATE NITROGEN IN THE SOIL AS A MEANS OF PREDICTING THE FERTILIZER NITROGEN REQUIREMENTS OF BARLEY

Abstract

In 22 field trials, over a seven-year period, highly significant correlations were found between nitrate nitrogen to various depths in the soil profile at seeding time and the uptake of nitrogen by the above-ground portion of barley at harvest. The best correlation was found at a depth of 61 cm, where the r 2 value was 0.84. Barley yields were shown to be highly significantly correlated with the uptake of nitrogen, the r 2 value being 0.86. These data, combined with a factor for the efficiency of utilization of a nitrogenous fertilizer, were used to derive an equation which predicts the amount of fertilizer nitrogen required for a particular barley yield.