Start off by doing a complete soil analysis first and see what your soils are needing in macro and micro nutrients as well as your ph levels. Next spray your areas your wanting to plant with glyphosate at least 41% concentrate. Allow about 10 to 14 days to dry up and then mow and burn the dried matter off the field if you can. Then disc your soil a couple times and if you have time let it sit for about 7 to 10 more days and go back and look for any new green growth. Sometimes you can have a dormant seed bed beneath the soil surface. If you see fresh green growing spray again with Glypho( round up) and let it set for 7 to 10 days and the you can disc and prep your soils for planting. This seems like alot of work but its one of the most effective ways to help combat weeds and grasses and keep them form overtaking your plots.