downy brome and cheat grass are different from wild oats. My experience is that downy brome and cheat grass germinate in the fall.  I don't have experience with wild oats.  A webpage from California says wild oats bloom from March thru June - hence they germinate in the fall.  a webpage from Cornell (New York) says wild oats germinates in the fall in southern California and germinates in the spring in the rest of the country.  That kinda makes sense to me.  So, I would guess that Wild Oats will germinate in the spring in Kansas; however, you could be seeing downy brome or cheat grass.