The Effect of Novel Soil Amendments on Roadside Establishment of Cover Crop and Native Prairie Plant Species
Samuel Gale, David D Biesboer
Report no. MnDOT 2004-41
The re-establishment of native plant species has been a principle objective of managers of roadside vegetation for many years. However, the establishment of native species, especially on the near inslope of roadsides has always been problematic. Soils of inslopes are generally nutrient poor, lack organic matter, and experience extreme microclimates of heat and nearly continuous drought. This report examined the concept that application of amendments to the soil or over the soil might have the capacity to increase fertility, increase soil moisture, or moderate the harsh microclimate of the inslope. In this study three different soil amendments/treatments were used to modify inslope soils including application of erosion control materials (ECMs) and enhancing soils with organic material. The two ECMs were products capable of changing soil temperatures, inhibiting soil moisture loss and/or enhancing the moisture aspect of the soil surface microclimate. The addition of organic matter is known to increase both soil water holding capacity and fertility. Although these products and treatments performed as expected, the overall conclusion of this study was that establishment of native species within two meters of the roadside was not enhanced by these treatments. Invasion by competitive weeds and weather (e.g., severe droughty conditions) appear to control the establishment of native species in the soils very near to the shoulder of roadsides.