Round-Up is the Monsanto brand name for Glyphosate. Their patent is up and others can offer the same chemical. The generic "brand" I use is Eraser. There are other "brands". Last time I bought some it was about $50/2.5 gallons for 40%. In my opinion, something that might work for this 40 acre layout might be to do the edges - about 50 yards wide. But I am only guessing because I don't have a clue about the locations of woods lines, creeks, etc.
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