Corn farming, ethanol production, and water quality
Corn production is a water intensive process.
Corn farming in the United States is extremely fertilizer- and pesticide-intensive. Due to the recent expansion of ethanol production and land acreage allotted to corn farming, water quality is seriously threatened by the increased use of chemical fertilizers and pesticides.
Excessive fertilizer runoff from corn cultivation contributes to the ever growing dead zones in the Gulf of Mexico and the Chesapeake Bay, areas so depleted of oxygen that they cannot sustain life. Moreover, pesticide leaching threatens the health of humans and wildlife as traces of these chemicals are found in groundwater used for drinking.
- Corn, as compared to all other ethanol-producing crops, has the greatest application rate of both fertilizers and pesticides per hectare.
- Corn production consumes 40% of all commercial fertilizers used on crops in the United States; commercial nitrogen is applied to 98% of corn fields and commercial phosphate to 87%.
- The US Department of Agriculture estimates that corn crops are treated with 138 pounds of nitrogen fertilizer per acre and 58 pounds of phosphorus fertilizer.
- The application rates of nitrogen fertilizer are often more than twice as much as the crop absorbs. Between 40 and 60% of the fertilizer applied to corn remains on the field as waste. This waste leaches into groundwater, streams and rivers, contaminating drinking water supplies and creating aquatic dead zones.
- According to the US Department of Agriculture, 95.8% of corn crops are treated with some kind of pesticide. The National Agricultural Statistics Service estimates that in 2005, corn crops consumed 157 million pounds of herbicides and 4.8 million pounds of insecticides.