Rapid change in soil properties after converting grasslands to crop production

Authors: STROCK, JEFFREY - University Of Minnesota; Johnson, Jane; TOLLEFSON, DAVID - Minnesota Department Of Agriculture; RANAIVOSON, ANDRY - University Of Minnesota

Submitted to: Agronomy Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/14/2022
Publication Date: 5/16/2022
Citation: Strock, J.S., Johnson, J.M., Tollefson, D., Ranaivoson, A. 2022. Rapid change in soil properties after converting grasslands to crop production. Agronomy Journal. 114(3):1642-1654. https://doi.org/10.1002/agj2.21045.
DOI: https://doi.org/10.1002/agj2.21045

Interpretive Summary: Beginning about 150 years ago with the arrival of European farmers, most of the prairie was converted to farmland used to grow annual crops. Converting prairie that is mostly perennial grasses into annual row crops greatly changed the soil properties. A small area of remnant prairie was sacrificed to understand how quickly some of the changes may have occurred during the historic shift from prairie to agriculture. Soil properties were measured to about three feet (one meter) before and after converting the conversion. Soil properties measure include bulk density, soil carbon, soil nitrogen and pH. Soil carbon is closely related to soil organic matter; thus, it is considered to be good measure of overall soil health. We also measured how water moves into and within a soil. Within two years a loss of soil carbon was measured. Also, how water moved into and within the soil was adversely impacted by the change. This study demonstrated that changes due to shifting into agriculture from prairie occurred quickly and that restoring some of the desired traits of the prairie might be difficult or impossible to achieve. This work is important to scientists, conservationalists, policy-makers and producers.

Technical Abstract: Changes to land management over the last 150 years, primarily the conversion of natural systems consisting of perennial grassland vegetation to agricultural production dominated by annual row crops, greatly changed soil properties and reduced the soil’s ability to infiltrate and store water in the soil profile. The objective of this research was to measure changes in soil physical, chemical and hydraulic properties after the conversion of perennial grassland vegetation to annual row crop production. A before and after approach was used to compare soil properties from a 0.31 ha field in southwest Minnesota. Our results showed that bulk density values following cultivation were only minimally affected. Two-years post-cultivation, there was an overall reduction of 15.7 soil organic carbon Mg ha-1 for the 0-1.0 m soil profile. Infiltration rates and soil sorptivity exhibited significant decreases following cultivation. Cultivation resulted in a negative shift in soil properties in this study. It is believed that conservation practices, i.e., no-till, cover cropping and/or perennial crops, would be required to restore some of the soil properties and hydraulic capacity of the system although these practices would likely not return to its original state.