The one point not mentioned here is the importance of seed to soil contact! whether you till or not, drill or broadcast most seeds need to make direct contact with the soil and the related microbial life there to germinate. Small seed like clover, turnips and radishes will find a way or a crevice in which to begin. larger seed like wheat, oats and cereal rye may sprout if your mowed grass holds enough moisture but if they do not establish roots into the soil, the first hot or dry spell will kill it. Soy beans , dont even go there without breaking soil.