I turned over an acre, of my pasture sod, and planted RR BT corn, for my chickens. It has been cold and rainy, since I planted, and the corn is just now coming up. the grass has been growing just fine, and is threatening the corn. I bought a 3pt roller pump sprayer , with short booms, and would like to spray, as soon as it quits raining. I have a little booklet from roundup, but cant figure out how much per gallon, to use. there is too much info in the booklet, and if it is in there , then I've missed it. I have a 50 gal tank. anyone want to tell me how many oz per gallon, to kill grass?