Soil Chemistry as Affected by First-time Prescribed Burning of a Grassland Restoration on a Coastal Plain Ultisol

While grassland restorations have gained recent popularity throughout the United States, few restorations have been initiated on the highly weathered soils of the Mid-Atlantic Coastal Plain; thus potential soil response to grassland management practices, such as prescribed burning, are not clearly understood in this region. The objective of this study was to evaluate the impacts of prescribed burning on the soil chemistry of a young grassland restoration established on agricultural fields in eastern Maryland. The soil is a slightly acidic highly weathered Typic Hapludult with a sandy loam surface texture and low cation exchange capacity (CEC). In spring 2003, soil was collected in five intervals to a depth of 20 cm 1 d before and 11 d and 1 yr after a first-time prescribed burn. By 11 d after the burn, and following 4.6 cm of rainfall, soil pH had increased significantly in all depth intervals relative to pre-burn values. Prescribed burning also significantly changed the relationship of CEC, Ca, and Mg with organic matter within 11 d. Results indicated that the infiltration and dissolution of base-cation-rich, alkaline ash from several days of rain after the burn significantly changed the soil chemistry within a few weeks after burning. By 1 yr after the burn, the soil pH and organic matter did not differ from pre-burn conditions. The impacts of prescribed burning of a grassland on a highly weathered Ultisol, therefore, involve shortterm changes in soil chemistry, followed by dissipation within a year due to long-term buffering of the soils. (Soil Science 2005;170:913–927)