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Land of 10,000 (Polluted) Lakes

June 02, 2014 By Emma FitzGerald, Macalester College

Minnesota, the land of 10,000 lakes, got its name from a Dakota word meaning ‘clear water’. However, we may have to start thinking about renaming this great state to something more accurate. Pollution in lakes, streams, rivers, and groundwater is reaching destructive levels in Minnesota, due largely to the conventional monoculture farming that dominates the agricultural practices of the state.

A 10-year Minnesota Polution Control Ageny study found 70 percent of nitrate runoff comes from agriculture, with the highest levels occuring in corn-rich south central counties of the state. This is largely due to agricultural drain tile systems, which use pipes to move water rapidly out of the fields and into close by water sources. This water carries large amounts of nitrate, commonly found in fertilizers, which are used to supplement the lack of soil nutrients found in soil.



By planting only one crop continuously in the same area—mainly corn and soybeans in Minnesota—the soil becomes depleted of certain nutrients that that crop uses. Synthetic fertilizers are used to replenish these nutrients.

While it is understandable that it would be very difficult to measure all agricultural runoff in the state, it is also very worrisome. These large amounts of agricultural pollution threaten human health, as well as biodiversity. Nitrate in drinking water poses a serious risk for infants (consumption of large quantities can lead to ‘blue baby syndrome’). This is a large concern, given that in Minnesota most drinking water is supplied by groundwater.

This pollution also greatly affects aquatic life, something you have likely experienced if you have ever been to a lake teeming with algae. With excesses of nitrates in the water, aquatic plants, such as algae and seaweed, grow overabundant. This disrupts the balance of the ecosystem, and puts added stress on aquatic animals such as fish. Thick layers of plant life near the water surface also greatly decrease the amounts of sunlight that reach the plants in the lower levels of the water, resulting in these lower dwelling plants dying off.

Our position on the Mississippi means that our actions here do not just affect us. Every year about 158 million pounds of nitrates leave Minnesota by way of the Mississippi River. A lot of this ends up in the Gulf of Mexico, Minnesota being the sixth highest contributor of nitrogen to it. Excessive nitrogen pollution in the Gulf has led to an area referred to as the ‘dead zone’- an area with severely oxygen-depleted water unsuitable for marine life. We must make informed decisions about how we approach agriculture for the betterment of other communities, as well as our own. Pollution resulting from conventional agricultural run off is rapidly changing our ecosystems, and will continue to degrade Minnesota and areas surrounding the Mississippi River unless meaningful changes are made.

Minnesota needs to move faster and further when it comes to crop diversity. Doing so would allow for better and more balanced use of soil nutrients, improvement of balance of insect pests (lowering or eliminating the need for pesticides), water conservation, as well as erosion control.

Polyculture is often used in conjunction with organic farming, due to its natural defenses against pests and ability to maintain soil fertility. Widespread use of this form of agriculture would greatly benefit both human and ecosystem health in Minnesota, and the United States overall.

In addition to sustaining the surrounding environment, organic polyculture provides fresh, local food to regional communities. While this would present some technical difficulties given Minnesota’s climate, new practices such as ‘deep winter greenhouses’ present promising ways to continue the growing season on through the harsh winter.

Yes, polyculture does not have the same immediate rewards as monocropping corn or soybeans, but the long-term benefits for the local community and environment are profound. This is sustainable agriculture. The transition will take generations and wouldn’t eliminate monoculture, but it will be worthwhile moving in that direction.

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