EFFECT OF AMMONIUM AND NITRATE FORMS OF NITROGEN AND RESTRICTED WATER SUPPLY ON GROWTH AND NITROGEN UPTAKE OF WHEAT

Abstract

Wheat was grown with fertilizer-N, either as ammonium sulfate (treated with a nitrification inhibitor) or as calcium nitrate, and without fertilizer-N and with various water treatments, both in the field and in pots in the glasshouse. With adequate water, wheat produced the most dry matter (and grain) containing the most N when supplied with nitrate; when shortage of water limited growth, ammonium-N was as good as or better than nitrate-N for increasing dry matter production and N uptake. From stem extension to flowering, the leaves and stems contained twice as much NO₃-N when given nitrate-N as when given ammonium-N.