Water contamination: In Minnesota, we must reconsider which crops we plant
The news in the Jan. 14 issue of the Star Tribune that 1 in 8 Minnesotans are drinking nitrate-tainted water and that fertilizer escaping from row-crop fields is a main culprit comes on top of one of the toughest growing seasons in the state’s history. U.S. farmers have experienced the wettest 12 months since at least 1895. I can’t count the number of times last spring, summer and fall that I drove by Minnesota crop fields where equipment was mired up to its hubs; in some cases the construction equipment brought in to drag out the farm equipment was stuck as well.
Many of these fields are increasingly becoming what agronomists call “unstable yielders,” and that has a direct connection to the latest bad news about nitrate pollution. A recent Michigan State University study — which, over eight years, examined 70 million acres in 10 Midwestern states, including Minnesota, with unprecedented granularity — found that around a quarter of our cornfields are consistently unstable yielders as a result of being too wet or otherwise unsuitable for cropping. Because these low-yielders waste nutrients — the lower the yields, the less plant material there is to use up nutrients — they account for more than 40% of the nitrogen fertilizer escaping into our water as a pollutant and into our atmosphere as a greenhouse gas. Wasted fertilizer is wasted money. The study estimates farmers lose $1 billion in fertilizer annually as a result of unstable yielders.