Prior to crop planting, the entire experimental area received a pre plant burn-down application of glyphosate at 0.84 kg ha 1 in each of the first 10-yr, glyphosate at 1.12 kg ha in each of the next 5 yr, and paraquat at 0.84 kg ha 1 in the final year. All treatments were fixed in space for the duration of the study.
Use rates of individual herbicides for the non-glyphosate treatments for both crops were changed infre- quently in an effort to improve weed control.
The selected herbicide treatments though without a true control(non-herbicide treatment) al lows for the comparison of glyphosate only based herbicide manage ment program with an alternative herbicide management regime