what is the meaning of ureides?

Ureides are a group of compounds that are acyl derivatives of urea. Soybean plant export fixed nitrogen as ureides. An advantage of soybean as a crop is that it symbiotically fixes atmospheric nitrogen, rather than depend on the application of fertilizer nitrogen.  Ureides are synthesized in the nitrogen fixation process, has more nitrogen than to carbon, may accumulate in the plant and cause a feedback inhibition of nitrogen fixation under drying conditions or during drought.