Reducing Freshwater Toxicity while Maintaining Weed Control, Profits, And Productivity: Effects of Increased Crop Rotation Diversity and Reduced Herbicide Usage (23 pages)

Data from 2008−2015 showed that use of the low-herbicide regime reduced freshwater toxicity loads by 81−96%, and that use of the more diverse rotations reduced toxicity and system dependence on herbicides by 25−51%. Mean weed biomass in corn and soybean was <25 kg ha−1 in all rotation × herbicide combinations except the low-herbicide 3-year rotation, which contained ∼110 kg ha−1 of weed biomass. Corn and soybean yields and net returns were as high or higher for the 3- and 4-year rotations managed with the low-herbicide regime as for the conventional-herbicide 2-year rotation.