by Austin, Karin, Jack and Raegan
Everything is linked, from plants to animals, from insects to microbes, and even from soil to air and water. When agricultural systems only grow crops in the summer, as with corn and soybeans, that cycle is broken. When land is left fallow after fall harvests and through the winter, the soil is left unprotected from erosion, temperature swings, and the cycling of water, nutrients and gases. It also eliminates habitats for animals that need living roots to survive. Cover crops prevent this break in the living plant cycle, and so prevent these problems. When cover crops die, their residue is recycled back into the system, further building soil fertility.
Plants sown in the fallow period between one crop and the next to extend the time that ground is covered and living roots are in the soil.
“The key to preventing nitrogen loss in soil is not whether it comes from fertilizer or nitrogen fixation, but rather always having plants there to take up any soluble nitrogen.”
USDA/ARS Plant Scientist
by Dawson, Justin and Timothy
Iowa was once covered in wetlands. They provided a habitat for Iowa’s wildlife and filtered excess nutrients before they reached nearby rivers. When Iowa was settled, these wetlands were drained to create farmland. New techniques are now needed to remove the large amounts of nitrogen used in farming. Can wetlands be the answer?
Water enters this wetland from tile lines draining from one thousand acres of nearby agricultural land. Before water in this wetland flows into rivers that eventually lead to the ocean, the wetland will act like a purifying filter, reducing nutrients through a combination of particle settling, volatilization, and absorption. Some nutrients are also assimilated by plants, algae, and denitrifying bacteria in the water, which convert nitrate into harmless nitrogen gas. In Iowa, 150-300,000 wetlands would be needed for effective nitrogen reduction of the state’s agricultural runoff.
Kent Schwartz implemented this wetland 10 years ago with support from the Conservation Reserve Enhancement Program (CREP) to explore new methods for nitrogen removal as well as create habitat for wildlife. A water sampling machine takes sample of the water leaving the wetland every six hours; these samples are tested to monitor the nutrient levels in order to measure the wetland’s effectiveness.
A strategically placed wetland designed to remove excess nutrients from field drainage before the water reaches rivers and other major waterways.
An offshoot of the Conservation Reserve Program (CRP), the country’s largest private-land conservation program. Administered by the Farm Service Agency (FSA), CREP targets high-priority conservation issues identified by local, state, or tribal governments or non-governmental organizations. In exchange for removing environmentally sensitive land from production and introducing conservation practices, farmers, ranchers, and agricultural land owners are paid an annual rental rate. Participation is voluntary, and the contract period is typically 10–15 years.
Microorganisms that convert nitrogen oxides back to gaseous nitrogen
by Sophie, Alec, Joey and Jake
Agricultural production has led to the decline of many aquatic ecosystems due to increased nutrients, including nitrate. While nitrate at levels of 10 PPM are considered unhealthy, water tests on Rosie’s land have measured nitrate levels up to 50 PPM. Rosie and her husband know that planted riparian buffers can be an effective method for reducing these nitrate levels, so theirs consists of showy goldenrod, Canadian goldenrod, elderberry, other shrubs and cedar trees. Rosie’s hope? That other farmers to do the same.
“It’s just a drop of water in the ocean, but it’s our drop.”
Conservation-minded Land Owner
Wall Lake, IA
Native trees shrubs and grasses planted alongside a body of water protect soils from erosion and filter agricultural runoff and pollution from ground water.
by Brycen, Aaron, Kylie and Jackson
Dan Jaynes and his colleagues have been using monitoring wells, soil sensors and pressure transducers to collect soil and water quality data on nitrate leaching at dozens of saturated buffers since 2010. If their results can establish that saturated buffers are an efficient tool for nitrate sequestration, then the practice could become eligible for USDA cost share programs, making it easier for farmers to adopt the practice on their own fields.
“Saturated buffers enhance the natural denitrification potential of riparian buffers in tile drained landscapes. The riparian buffer has been modified to allow some tile drain water to infiltrate along the length of the buffer as shallow roundwater.”
National Laboratory for Agriculture and the Environment
Running a tile line [perforated underground pipe] along a riparian buffer can enhance denitrification and serve as a cost effective, low maintenance nutrient reduction practice.
A vegetated, usually forested area beside a stream which helps shade and partially protect a waterway from the impact of adjacent land uses.
A microbially-facilitated process that reduces nitrate and usually results in the escape of nitrogen into the air.
by Derek, Lena and Mike
Iowa State University’s “Science-based Trials of Row-crops Integrated with Prairie Strips” or STRIPS placed autosamplers on Iowa farmland to analyse water directly in the field and provide data on total suspended solids, nitrogen, nitrate, and phosphorus. Their finding proved that removing 10 percent of a row-crop field from production and planting strips of perennial prairie grasses in strategic locations reduces sediment loss by up to 95 percent and water runoff by 40 percent. In addition, prairie strips, whose roots anchor and soak up runoff water, can reduce phosphorus loss by 90 percent and nitrogen loss by 80 percent, as well as increase pollinator and wildlife habitat.
The first STRIPS experiment was seeded in 2007 at Neal Smith Wildlife Refuge. Now the focus is on expanding the practice to private farms around Iowa. Prairie strips are similar in cost to other conservation practices like cover crops, but prairie strips provide additional benefits for the environment, including increased native biodiversity to support pollinators, birds and other wildlife. Tim Younquist works on outreach, talking to interested farmers about how prairie strips can work for them.
Small areas of prairie strategically placed on the contours of a field to keep soil in place, slow down water, and reduce nutrient loss.
“With prairie strips the water goes from running off the field to walking off the field.”
Farmer Liason, Department of Agronomy
Iowa State University
by Louis, Ben and Blake
An edge of field structure, usually a subsurface trench containing a carbon source such as wood chips, that denitrifies subsurface agricultural drainage flows to reduce nitrate levels and improve water quality.
Step 1: Drainage Control Box – The tile water enters through the drainage control box, which offers a bypass if the water volume gets too high.
Step 2: Filtering – The water then filters through a bed of woodchips, colonized by naturally occurring bacteria. In the woodchips the bacteria catalyze a series of anaerobic reactions that break down and remove nitrates from the water, releasing nitrogen gas and small amounts of nitrous oxide.
Step 3: Drainage Control Box II – The water flows through a second box that can change the water level in the woodchip bed and flows out the tile outlet.
“I’m spending money most farmers wouldn’t.”
Tesdell Century Farm
South of Slater, IA
A nitrate reduction method that involves underground trenches filled with woodchips, through which tile water flows before exiting the line. The woodchips serve as a substrate for bacteria that break down the nitrates through chemical processes. Bacteria “eat” the carbon in the woodchips, “breath in” nitrate from the water, then “breathe out” N2, thus reducing the nitrate content of the water before it enters surface runoff.
by Sophie, Alec, Joey and Jake
THE AGRICULTURE CONSERVATION PLANNING FRAMEWORK offers a watershed approach to conservation planning that uses technical and software tools to help users generate detailed maps. A detailed terrain analysis helps identify areas which may contribute disproportionate amounts of nutrients, sediment, or runoff water to a water body, and the precise location for suitable and effective conservation practices to mitigate these concerns. The maps are then “ground-truthed” and used to promote discussions of watershed-scale interactions, even when working with individual landowners.
These conservation practices can include the installation of SURFACE INLETS in the depressions of cropped fields to drain surface water. By implementing grass buffers and sand-bed intakes around these depressions, less sediment and phosphorus loads leave the fields. Strips of grassy vegetation or GRASS WATERWAYS can be strategically planted where accumulated water flows to ditches or creeks to reduce the velocity of runoff, prevent gully formation, and increase soil strength to mitigate erosion. COUNTOUR BUFFERS can be planted across slopes and along topographic contours to intercept water flows, reduce sheet and rill erosion, and keep soil up on the field.
ACPF was developed by Mark Tomer and his team at the USDA-ARS in Ames, IA.
“The ACPF provides options based on science, not regulations based on political or economic drivers.”
Agricultural Sciece Technician
An approach that incorporates precision conservation concepts into the agricultural watershed planning process; a planning toolbox that uses topographical data to identify and map a full range of options to manage water flows and reduce nutrient loss by intercepting and treating water where it moves and accumulates on the landscape.
by Derek, Lena and Mike
Practical Farmers of Iowa was founded in 1985, in the midst of Iowa’s agricultural crisis, based on the concept of a farmer’s coop. This farm-led nonprofit organization is a unique collaboration between farmers, the Leopold Center, and Iowa State University that shares information to help farmers practice agriculture that benefits both the land and people.
“PFI is an extended family of like-minded people … a very diverse group of people that has a tremendous amount of knowledge and education through on-farm research.”
Carney Family Farms