One of the many characteristics that makes soybeans a desirable crop is their ability to fix nitrogen. In order to enhance this ability, it is ne-cessary to look at the variation among various cultivars throughout their life cycle. Genetic studies for Spanish clover (Desmodium sandwicense E. Mey) by Pinchbeck et al. (1980) showed a significant difference among genotypes in their ability to fix nitrogen.
Garner, E. Ramona; Sapra, Val T.; and Floyd, McArthur
"Research Notes : United States : Influence of genotype and growth stage on nitrogen fixation in soybeans,"
Soybean Genetics Newsletter: Vol. 12
, Article 18.
Available at: http://lib.dr.iastate.edu/soybeangenetics/vol12/iss1/18