Nothing affects more land in Illinois than growing crops.
Making farming possible on this scale required by far the most significant of the changes humans have wrought on the state's ecosystems. Beginning in the 1880s and continuing into the 1930s, a succession of innovations came into wide enough use to transform this bucolic Illinois farmscape. Commercial fertilizers and hybrid varieties of corn made possible such higher yields that, beginning about 1940, profits from grain sales rivaled those earned by animal husbandry. The average Illinois cornfield that yielded about 50 bushels per acre in 1945 yielded nearly 120 bushels per acre in 1990. In their place farmers have planted row crops, especially soybeans, acreage of which has more than doubled since 1945.