WILL THE RIVERS CLAP THEIR HANDS?

Rivers are a primary source of supply for many water utility systems. Such utilities are responsible to treat river water in compliance with applicable safe drinking water regulations. As rivers and their tributaries meander through agricultural land, they are susceptible to farm field soil erosion and fertilizer runoff. Perhaps the most troublesome constituents of such runoff are the nitrates. In the United States, there are strict limits on the permitted levels of nitrates in drinking water, which impose in many cases costly treatment protocols.

For example, in its 2014 annual report, the Minnesota Department of Health indicates that agricultural related nitrate pollution is a growing threat to the state's drinking water from all sources. The report states: "Roughly half of Minnesota's land is in agricultural production, primarily in the southern and western parts of the state. Up to 20 million acres of Minnesota is in row crop production annually. Row crops, which include corn, soybeans, sugar beets, and potatoes, are a major contributor to Minnesota's economy. However, since soils in row-crop production can lose nitrate during the non-growing season, these lands are the biggest influence on Minnesota's ground and surface water nitrate levels." (p.7)

Farm soil erosion is another issue for rivers. According to a published report, to mitigate erosion, farmers are switching to no till farming, a practice of planting crops without tillage of the soil. Stubble from prior crops is left on the ground. The new crop is planted by drilling seed into the soil without disturbing the ground by tilling. Accordingly, this practice tends to hold soil in place.*

So, could no till farming be the answer for both erosion and runoff control? Maybe not, according to another published report. It states that researchers have found that fields managed by conventional and turbo-tillage practices can produce lower concentrations of pollutants in runoff than those managed by no till practices.**

Maybe further research will conclude that both new seed and fertilizer could be drilled into the soil, leaving the surface otherwise undisturbed. This approach, of course, could cause increased costs for agricultural interests. But it also could assign costs to the cost causers and reduce treatment costs for utilities and their customers. Perhaps, an alternative approach could be no till practices for erosion control and more modest and efficient application of fertilizers. Whatever, with further research, maybe some day rivers will have less concern over erosion and runoff, and will clap their hands.

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*Lutey, Billings Gazette, republished in
Rapid City Journal, April 27,2015,p.A8

**Environmental Science & Technology,
November 20, 2012