Soil variability and fertility considerations affecting establishment of erosion control vegetation on Piedmont roadcuts

ABSTRACT:

Roadside cutslope soils derived from four distinctively different geological materials were evaluated for physical and chemical properties important to turf establishment for erosion control. Data obtained from morphologic horizon samples as deep as 2.8 meters (10 feet) documented extreme vertical variation in soil properties. Each of the cutslopes exposed soils with well-defined argillic horizons containing 35 to 71 percent clay. The underlying saprolite materials were generally loamy in texture. Base saturation ranged from 2 to 78 percent and soil pH varied from 4.5 to 7.2. Based on routine roil fertility analyses for 41 soil horizons, recommendations ranged from 0.7 to 1.5 times the phosphorus pentoxide (P₂O₅) rate currently used by state agencies for roadside erosion control plantings. These soil test recommendations do not allow for high levels of phosphorus (P) fixation, which occurs in many of these soils. Similarly, soil test recommendations were 0 to 0.9 times the potassium oxide (K₂O) and 0 to 3 times the lime rates used currently. Soil testing information for specific soil management areas and conditions has great potential for reducing costs and improving the effectiveness of roadside erosion control programs.