I use to put a set of nozzels under the crimper & spray Mustang Max on the dirt under the sawth..99% kill for $.50 a acre.   off label, but cheap & effective. Reason for Mustang max it was labeled for full rate 3 days before cutting, and I was putting less on the dirt than that, very little hay touched the chemical.  But disk sawthers run so fast that I didn't want to pack the water needed