Research on the benefits from prairie strips placed in crop fields continues to grow at Iowa State University.
STRIPS, or “Science-based Trails of Rowcrops Integrated with Prairie Strips,” is a project investigating strips of farmland converted to native prairie plants. These strips are typically created between crops, at the edge of farm fields, or on lower performing fields.
Agronomy professor Marshall McDaniel has been working with Iowa State’s STRIPS team. The team has found that prairie strips have disproportionate benefits when incorporated into fields. Small shifts in the proportion of land used for prairie strips can have large positive effects on environmental quality.
“You take out a small portion [and convert to prairie strips or CRP], and you get disproportionate benefits to the land, including to wildlife; birds will live and breed in there and pollinators will increase. Some studies have shown the strip acts as a filter to reduce sediment erosion and loss of nutrients off the field as well,” McDaniel said. “I have a student currently looking at what happens under the prairie strip soil.”
McDaniel knows that prairie strips can also increase soil carbon, evidenced by a recent paper that was publishing in December in the Soil Science Society of America Journal. The team sampled 241 soils in northern Iowa and southern Minnesota on farms, restored CRP grasslands planting from 2 to 40 years ago, and native grasslands. They also sampled different areas of the field to look at how hilltops and depressions might change at faster or slower rates with grassland restoration.
The soils were then analyzed for a suite of soil health indicators; like total organic carbon, maximum water holding capacity, bulk density, bio-available carbon (e.g. microbe food), and more. The results showed that native grasslands had superior soil health over cropland and most CRP soils. McDaniel’s group also found that carbon recovers slowly when cropland is converted to CRP grassland, at about 1% increase in carbon per year, but that hilltops recovered fastest. Recovery of the bio-available carbon in the soil was much faster than other soil health indicators, and consistent across the landscape, highlighting its potential for use as a soil health indicator after changes in management.
Planting CRPs among crops can be beneficial to not only the soil and environment, but also to the bottom line as well. The Farm Bill, newly approved at the end of 2018, enables farmers to collect federal conservation payments for installing prairie strips on their land. This goes along with the recent trend with carbon markets – where corporations and individuals are looking to reduce their carbon footprints. Several companies are considering paying farmers to sequester C in their soils, and McDaniel thinks prairie strips could become not only environmentally friendly, but perhaps even profitable.
“The idea is you trade carbon credits to reduce your overall footprint,” McDaniel said. “There are a lot of private companies getting into this and I think they see the writing on the wall, climate change is here, we need to do something about it and they are attempting to offset carbon emissions.”
Prairie strips could join practices like no tillage, and planting cover crops or more diverse crop rotations to sequester carbon in the soil. McDaniel said further testing in his lab would address whether prairie strips have a positive, negative or neutral effect on the soil underneath and surrounding cropland.