Constructed Wetlands Show Promise In Managing Nutrients

Jun 21, 2017

Wetlands are among the most productive ecosystems in the world, comparable to rainforest and coral reefs. Now, modern agriculture is trying to capture some of nature’s wetland magic as a means to manage nutrients on the farm.

State and national corn organizations’ staff that work on water quality issues recently toured the Franklin Research & Demonstration Farm near Lexington, Illinois, to learn more about how research into “constructed wetlands” might provide another serious tool to help farmers manage nutrients like nitrogen and phosphorous.

The tour provided an educational opportunity for staff of the National Corn Growers Association and state corn staff representing Illinois, Colorado, Indiana, Kansas, Kentucky, Michigan, Minnesota, Missouri, Nebraska and Ohio who met in Bloomington, Illinois, to discuss initiatives to promote voluntary nutrient-management programs.

A constructed wetland is a man-made wetland that acts as a treatment system that uses natural processes involving wetland vegetation, soils, and their associated microbial activity to improve water quality.

In the case of The Franklin Farm project, the wetlands being researched are designed to take tile water (not surface water) from nearby crop fields and slow down and clean the water, according to Ashley Maybanks, Mackinaw Science Specialist with The Nature Conservancy.

Wetlands function as nature’s kidneys, removing nutrients and sediment, as well as slowing down the flow of water before it reaches creeks, streams, and rivers. When placed near agricultural lands, constructed wetlands can catch and absorb nutrients from farm fields. At the Franklin Demonstration farm, researchers and farmers are learning how effective constructed wetlands can be, and specifically, the size and amount needed to help clean nutrients from water that passes through tile drains.

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Video: Spring 2026 weather outlook for Wisconsin; What an early-arriving El Niño could mean

Northeast Wisconsin is a small corner of the world, but our weather is still affected by what happens across the globe.

That includes in the equatorial Pacific, where changes between El Niño and La Niña play a role in the weather here -- and boy, have there been some abrupt changes as of late.

El Niño and La Niña are the two phases of what is collectively known as the El Niño Southern Oscillation, or ENSO for short. These are the swings back and forth from unusually warm to unusually cold sea surface temperatures in the Pacific Ocean along the equator.

Since this past September, we have been in a weak La Niña, which means water temperatures near the Eastern Pacific equator have been cooler than usual. That's where we're at right now.

Even last fall, the long-term outlook suggested a return to neutral conditions by spring and potentially El Niño conditions by summer.

But there are some signs this may be happening faster than usual, which could accelerate the onset of El Niño.

Over the last few weeks, unusually strong bursts of westerly winds farther west in the Pacific -- where sea surface temperatures are warmer than average -- have been observed. There is a chance that this could accelerate the warming of those eastern Pacific waters and potentially push us into El Niño sooner than usual.

If we do enter El Nino by spring -- which we'll define as the period of March, April and May -- there are some long-term correlations with our weather here in Northeast Wisconsin.

Looking at a map of anomalously warm weather, most of the upper Great Lakes doesn't show a strong correlation, but in general, the northern tiers of the United States do tend to lean to that direction.

The stronger correlation is with precipitation. El Niño conditions in spring have historically come with a higher risk of very dry weather over that time frame, so this will definitely be a transition we'll have to watch closely as we move out of winter.