Prepare the soil by discing or harrowing on a deep setting. Using an initial pre-emergent herbicide keeps weeds and other grasses from choking out chufa. After discing and agitating, weed seeds make their way to the surface and will germinate just as fast as your chufa. Using a selective herbicide, such as Treflan, and incorporating it into the soil will help ensure chufa will be weed free. You also can work in an initial starter fertilizer into the soil, such as a 17-17-17, to jump-start the chufa.
Note: Do not use a barrier-type pre-emergent, as it will inhibit the chufa from sprouting. Treflan and Prowl are the recommended pre-emergents, applied at one quart per acre.
Roundup, clethodim or any other fop or dim, the list is pretty short on what you can't spray. Treflan will not inhibit it premergent, dual is the only thing that will and it's only slight suppression. Crossbow could be used over it but it doesn't do anything to grass, only broadleaf.