Influence of long-term application of feedlot amendments to cropland on ground elevation, Ah horizon depth, and soil color

Few studies have examined the effect of long-term application of feedlot manure on ground elevation, Ah horizon depth, and color of surface soil. The objective of this study was to examine the effect of manure type (stockpiled vs. composted feedlot manure), bedding (straw vs. wood chips), and application rate (13, 39, and 77 Mg ha−1 dry wt.) on these soil properties after 17 annual applications. There was also one inorganic (IN) fertilizer treatment and an unamended control. Elevations were measured using a total station, and the Munsell value and chroma measured on field soil and on fine-ground (<150 μm) soil using color charts. Manure type and bedding had no significant (P > 0.05) effect on relative elevation and Ah depth, but relative elevation and Ah depth increased with greater application rates (10.7 cm increase in relative elevation at 77 Mg ha−1). The Munsell color value was significantly lower or darker for amended than unamended soils and shifted the Chernozemic soil Great Group classification for some treatments from Dark Brown to Black. Overall, greater rates of feedlot manure increased the relative elevation and Ah depth of amended soils and made the surface soil darker, but manure type and bedding had no effect.