Submitted to: Nature Magazine
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/23/1995
Publication Date: N/A
Interpretive Summary: A number of previous investigations have shown that symbiotic nitrogen fixation in legumes is very sensitive to even modest soil drying. However, these studies have been limited to a few species including only soybean, cowpea, and black gram. The research reported in this paper was undertaken to determine if the sensitivity to drought was universal among grain legumes. In fact, this research showed that nitrogen fixation in virtually all other grain legumes, including common bean, peanut, and pea, was tolerant of drought conditions. These results indicated that species selection for drought prone lands may be especially important to obtain sustained nitrogen fixation by legume crop.
Technical Abstract: Grain legumes are critically important in many cropping systems because of their ability to fix atmospheric N2, and this importance is anticipated to increase with the need to develop sustainable agricultural practices. Unfortunately, N2 fixation has been found to be sensitive to modest soil drying in soybean [Glycine max (L.) Merr.], cowpea [Vigna unguiculata (L.)], and black gram (Vigna mungo (L.)], resulting in decreased yielding capacity. The present study showed that the drought sensitivity was not universal among legumes. Grain legumes which transport fixed nitrogen as amides were found to have N2 fixation activity that was less sensitive to soil drying than those that transport ureides, making them advantageous in dryland regions.