Update:
The final report was greater than 5 MB, so the executive summary was uploaded. The full final report is available by request at: rj.goos@ndsu.edu
View uploaded report
The objective was to calibrate the ureide tissue test as an index of adequacy of N-fixation. Ureide-N levels in the plant axes (stems plus petioles) at flowering of less than 1000 ppm were associated with yield loss and protein loss due to inadequate N fixation. Levels greater than 1500 ppm were associated with adequate N fixation. We also conducted a calibration, comparing the numbers of Bradyrhizobium japonicum in the soil, to the response of soybeans to inoculation. Whenever numbers of B. japonicum in the soil were greater than 100 per gram, there was no response to inoculation.