Measurement of Nitrogen Fixation by Soybean in the Field Using the Ureide and Natural 15N Abundance Methods

摘要: Nitrogen fixation by field-grown soybean ( Glycine max [L.] Merrill) was assessed the natural 15 N abundance and ureide methods. The field sites (five) genotypes (six, plus two levels of inoculation on Bragg) were chosen to provide a range proportions plant derived from nitrogen P ). Genotypes K466, K468, nts1007, nts1116 Davis included basis their reported tolerance suppressive effects nitrate nodulation fixation. Bragg as `nitrate-sensitive9 genotype. Seeds all inoculated at sowing with Bradyrhizobium japonicum CB1809 (USDA136). Amounts in soil profile (0-1.2 meter depth) ranged 70 (site 3) 278 kilograms per hectare 5), resulting large nodulation, δ values nodulated plants, relative ureide-N vacuum-extracted sap (VES) stem extracts, finally estimates P. There no relationship between amount plant-available N. Correlation matrices measured calculated parameters indicated generally weak correlations crop growth (dry matter N) symbiotic activity (nodule weight, N, ureide-N); strong highly significant measures (δ ureide-N; r = 0.79-0.92). Estimates 0 68% 6 56% (ureide) correlated 0.97). Results that method can be used confidence assess crops soybean.