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Opinion: Nitrates in groundwater: Think of the problem this way

I’m a farmer in southeastern Minnesota, the specific area of highest concern for nitrates in our groundwater (“Proposed fertilizer tax could aid nitrate cleanup,” March 2). Much of this region is underlaid with “karst geology” — fractured limestone very close to the surface, often with large cracks and crevices, including caves, running deep underground and directly to the aquifers that many wells draw their water from.

Some of the area, like on my farm, is overburdened with very deep, high percentage of clays — “glacial till.” There’s 120 feet of this over the bedrock on my farm. But only a few miles away, the limestone outcroppings are often visible along the valleys. | READ MORE