Ureides (degraded urea) are used to carry nitrogen out of some legumes nodules, including soybeans, and back into their aging organs.
Their nitrogen-to-carbon ratio is high.
Through a symbiotic association with nitrogen-fixing bacteria that live in root nodules, soybean plants may acquire atmospheric nitrogen.
The ureides, allantoin, and allantoic acid, which are also the main long-distance nitrogen transport forms from nodules to the shoot in soybean, are the by-products of fixation.
It is also moved by the xylem root system to shoots.