Try this...plant it and let it mature...spray it with 2%roundup...it will br brown and dry in 10 days and let it melt down...put the zero turn to it low as you can stand it or even better burn it...burn it and you will kill the germ on most of it and if it rains it won't sprout. If you just mow it the moisture will affect it....whatever just don't do the whole field at once.