THE RESPONSE OF PEARL-MILLET TO CHANGES IN NITROGEN CONCENTRATION OR FORM DURING GRAIN FILL

Pearl millet [Pennisetum glaucum (L.) R. Br. is a potentially productive, high-yielding grain crop in the southeastern USA. A lack of response in pearl millet grain yield to fertilizer N in field studies indicates pearl millet may be able to remobilize N from vegetative to reproductive tissue. The N remobilization capabilities of a plant can be affected by the form of N supplemented. The objectives of this study were to evaluate the effects of N-form ratio (NH4: NO3) on the N remobilization capabilities of pearl millet when N is removed from the nutrient solution at the boot stage and to evaluate the effects of changing N-form ratios at the boot stage on the seed yield and N content of pearl millet. Pearl millet was grown in solution culture under greenhouse conditions. There were 10 treatments: an initial NH4+; NO3 ratio of 3:1 followed by a change at the boot stage to either all NO3 no N, or a continuation of the initial ratio; an initial NH4+: NO/ ratio of 1:1 followed by a change at the boot stage to either all NO3+, all NH4+ no N, or a continuation of the initial ratio; and an initial NH4+: NO3+ ratio of 1:3. © 1990, Taylor & Francis Group, LLC. All rights reserved.