just a thought, don't you have a disk drill? The reason for this, my buddy had this same pattern in his corn a couple years ago, his father-in law put NH3 and MAP down with a Concord with wide sweeps on at an angle. Long story short, they found that the depth was off because of the worked chisel verse the hard not worked. Their pattern was in line with the rear sweeps. They put a rolling basket/packer and a good harrow on, and no more pattern.