The effects of prescribed fire on soil carbon pools and nutrient flux in oak woodlands of the Missouri Ozark Highlands.

by

Amanda L. Wolfgeher, Keith W. Goyne, and John M. Kabrick

Research Assistant (ALW), Soil, Environmental, and Atmospheric Sciences Department, 302 Natural Resources Building, University of Missouri, Columbia, MO 65211; Associate Professor (KWG), University of Missouri, 302 Natural Resources Building, Columbia, MO 65211; Research Forester (JMK), USDA Forest Service, Northern Research Station, 202 Natural Resources Building, Columbia, MO 6521.

Abstract – Prescribed fire can be used to meet a variety of forest management objectives, including the restoration and maintenance of Oak (Quercus spp.) woodlands. Since belowground sustainability influences above ground productivity, land managers are interested in understanding how fire affects short- and long-term soil productivity. Although fire has a historical presence in the Ozark Highlands, few studies have measured the effects of fire on soil physical and chemical properties in this region. The objective of this study is to quantify changes in soil solid carbon pools, nutrient concentrations, aggregate stability, and nutrient flux in newly burned sites and sites that have been burned multiple times. Study sites are located in Oak-Pine Woodland/Forest Hills Landtype Association in the Black River Basin of southern Missouri. Weathered from Roubidoux sandstone and Gasconade dolomite, soils at the sites contain large quantities of coarse fragments and reduced nutrient content. In 2015, fire was applied to sites that had no documented occurrence of fire for at least 40 years prior and sites that have been burned twice since 2002. Bulk soil samples were collected prior to the 2015 burn, immediately post-burn, and yearly thereafter at 0-10, 10-20, and 20-30 cm depths. The soil solution is continuously monitored at 10cm and 30cm depths using Plant Root Simulator (PRSTM) probes. Preliminary bulk soil property and nutrient flux data will be presented. By understanding the changes in storage and movement of plant required nutrients in Ozark soils, land managers can properly prescribe a fire regime that sustainably meets forestry objectives.