I talked with a grazing specialist about getting a clover monoculture (roughly) established in an old pasture. His suggestion would probably work for you as well. Spray with glyphosate once the grass is green and about 6-8" tall. A couple weeks later broadcast the equivalent of 50#/acre of buckwheat and cultipack or mow the dead grass. Buckwheat is a 90 day plant, so in 3 mos it's dead anyway. Then in early fall/late summer broadcast oats/turnips to the dying/dead buckwheat and mow or cultipack. Oats/turnips shouldn't last through the winter. Then that winter frost seed the plots with your choice of clover. He stated he's seen this work very well for getting a lot of clover established in an area without doing tillage.
I'm planning on trying this on a couple of small, hard to reach plots this year.
