RE: Soybean plot
The best advice I can offer on clovers is:
Plant with weed control in mind from Day One. A compacted soil, level seeded clover plot will outperform a hastilly seeded - non compacted plot - HANDS DOWN.
Even Still - You Must Mow, you may have to supply P&K, you may have to spray.
General mowing should be enough to maintain a plot once established - If establishing is a problem - then USUALLY PH and/or moisture is the culprit.