In a new Iowa State University study, researchers will test how the environmental benefits of planting strips of prairie among row crops change over time. The information gathered will fill an unexplored gap in prairie strip research that stretches back over a decade.

ISU agronomy professor Richard Cruse and colleagues recently received a three-year, $746,000 grant from the Foundation for Food and Agriculture Research (FFAR) to conduct experiments to gauge how quickly soil health changes after the use of prairie strips. They’ll also examine how quickly soil health reverts to its previous state after strips are removed and the land is converted back to crop production.

The work will consider factors such as erosion and surface hydrology, and how water moves through prairie strips and surrounding fields. The researchers will also conduct an economic analysis of prairie strips, which will consider new income streams the strips may generate. 

Seeking answers

Cruse says previous research on prairie strips — a farmland conservation practice in which strategic locations in fields are seeded with prairie grasses and flowers — has documented how the strips slow erosion and provide habitat for wildlife.

But questions remain about how long it takes for those benefits to show up, and how quickly they disappear when the strips are converted back into row crops. The research team will attempt to answer those questions.

“If farmers want to rotate the location of a strip in a field or terminate a long-standing prairie or establish a new one, we want to provide data on how that will affect soil health,” Cruse says.

To find those answers, ISU scientists will convert some existing prairie into row crops and measure several variables related to soil health over time. They’ll also convert some acres devoted to row crops into new prairie.

The experiments will take place at the Neal Smith Wildlife Refuge near Prairie City in central Iowa, where ISU researchers have conducted previous strips-related research. Additional experimental sites will be located on land belonging to cooperating farmers in Iowa and Missouri. 

Measuring effects on soil health

The researchers will use tea bags to help measure biological activity in the soil, an important measure of soil health, Cruse says. Different tea varieties contain various proportions of nitrogen and carbon. Substances with high nitrogen content tend to decay more rapidly when buried in soil, while substances with high carbon decay slowly.

The researchers will bury the tea bags in the soil of experimental sites and weigh the tea bags at determined intervals. Tea bags that exhibit rapid weight loss indicate high rates of biological activity in the soil, which is usually ideal for crop production.

In addition, the researchers will use modeling technology to create a statewide map of topsoil depth. They’ll then take core samples to measure the accuracy of their computer modeling methods. Cruse says the data will help researchers understand how prairie strips affect erosion on surrounding land.

Dollars and sense of prairie strips

The project will examine the economic implications of prairie strips. For example, converting land from row crops into prairie reduces the overall amount of grain a farmer harvests, but some sections of fields regularly produce yields lagging behind surrounding acres. This can be due to soil considerations, topography or a range of other reasons, Cruse says. But these marginal acres often don’t produce enough grain to justify the necessary input costs, and planting prairie on those sections might make more financial sense. 

“Prairie strips might create new revenue streams, as well,” he says. For instance, the project’s economic analysis may look at the possibility of leasing land near prairie strips for hunting or its suitability as habitat for honeybees.

Improving soil health increases farm sustainability

Corn and soybeans are crucial to supplying affordable and nutritious food. However, the nutrient depletion caused by crop production reduces future yields, which undermines long-term farm sustainability and profitability. In fact, soil erosion costs the ag industry about $44 billion annually and increases production costs by about 25% each year. 

Using the Foundation for Food and Agriculture Research (FFAR) grant, ISU agronomy professor Richard Cruse is conducting research aiming to restore soil health by identifying how to use practices that provide continuous living cover on corn and soybean fields, including prairie strips and cover crops. Such practices ensure the presence of live roots in the ground throughout the entire year, which can stabilize soils, enhance soil health and improve farm-level economics. 

“Prairie strips have been discussed in research circles for a decade,” says Cruse, who is director of the Iowa Water Center at ISU. “We’re looking at the environmental and economic impact of prairie strips over time.”

Farmers have expressed interest in prairie strips and cover crops; however, knowledge gaps and perceived obstacles stymie their widespread adoption. This grant will identify the most effective practices and tackle barriers that prevent farmers from adopting these practices. 

“Prairie strips haven’t been adopted as quickly as some other management practices,” Cruse says. “We want to look at possible obstacles to implementation, like the flexibility of converting strips back to farm ground and changes that impact soil health, as well as economic factors. For a farmer to make a change it has to either be net positive or neutral at the very least.”

Farmers need more information about impacts on soil erosion, changes in soil properties, and the yield and financial benefits of improving soil health. Cruse’s team will develop a model to inform the integration of soil management practices, while simultaneously maintaining current cropping systems, says Sally Rockey, FFAR’s executive director. The goal is to help farmers limit soil loss, protect water quality and improve soil health.  

“This research project has the potential to advance soil management practices that protect farmlands for generations to come, and help ensure that these farms remain profitable,” Rockey says. “The added benefit of this Seeding Solutions Grant is it determines the best solution for Midwest corn and soybean farmers and helps them easily adopt these practices, so their farms can continue to thrive.”

Sources: ISU and FFAR, which are responsible for the information provided and is wholly owned by the sources. Informa Business Media and its subsidiaries aren’t responsible for any of the content contained in this information asset.