Sethoxydim (Poast) + crop oil + ammonium sulfate. Mix all 3 together and apply at a rate of approximately 2 pt. / acre. Done this. Works great. Poast will kill the grasses but not broad leaf plants. The crop oil and ammonium sulfate help the Poast "stick" to the weeds.
If your crop has been invaded by broad leaf stuff, one method I have heard of but not tried is to apply a very light dose of Round-Up ..... 40% stuff at about 1 pt./acre. Supposed to stun the clover but not wipe it out. But I would conduct a test area before spraying the entire field !