al., 1998) experiments have shown that N2 fixation in soybean is especially sensitive to water deficits and deIncreasing N2 fixation tolerance to drought has been hindered by creases before transpiration or photosynthesis. Furtherthe labor and costs of quantifying N2 fixation using 15N methodologies. The relative abundance of ureides (RAU) in plant tissues has been more, soybean grain yield und...