The response of pearl millet to changes in nitrogen concentration or form during grain fill |
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| Authors: | R L Smith H A Mills C S Hoveland W W Hanna |
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| Institution: | Department of Agronomy , University of Georgia , Athens, GA, 30602 |
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| Abstract: | 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 + : NO3 ‐ 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 followed by a change at the boot stage to either all NH4 + no N, or a continuation of the initial ratio. Pearl millet dry matter accumulation was insensitive to changes in N‐form ratio or N removal at the boot stage. The lack of seed yield response to removal of N was a result of pearl millet utilizing N present in culms and leaves for seed production. Applications of N after the boot stage did not increase seed yield, but led to luxury consumption of N. |
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