Determining Symbiotic Nitrogen Fixation in Dry Bean Cultivars Using Ureide Method and Isotope Dilution Techniques |
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Authors: | Debankur Sanyal Robert Jay Goos Amitava Chatterjee |
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Affiliation: | Department of Soil Science, North Dakota State University, Fargo, ND, USA |
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Abstract: | Symbiotic nitrogen fixation (SNF) is an environmentally safe source of nitrogen (N) to the crop plants. In total, 12 dry bean (Phaseolus vulgaris L.) cultivars from pinto, navy, black, and kidney market classes were inoculated with rhizobia and grown in a greenhouse. SNF was estimated using isotope dilution technique and ‘ureide’ method. The amount of SNF ranged between 33 and 68 mg N plant–1 when determined using 15N isotope dilution and followed the order: pinto > navy > black > kidney. Percent N derived from atmosphere (%Ndfa) significantly varied between 49% and 90% at V3 and between 71% and 98% at R2 stages. The outcomes of the experiment suggested that dry bean cultivars from different market classes have variable N2 fixation ability, and fertilizer N required should be calculated according to their SNF potentials and N need of a specific market class or cultivar. Stable isotope dilution should be used as the standard procedure to estimate the SNF in dry bean. |
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Keywords: | 15N dry bean isotope dilution Rhizobium symbiotic nitrogen fixation ureide |
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