Authors: Zani Dembure*, , C. Brannon Andersen, Department of Earth and Environmental Sciences, Furman University, Greenville, SC 29613
Topics: Environmental Science, Anthropocene, Soils
Keywords: soil, agriculture, grazing, soil carbon, soil nitrogen
Session Type: Poster
Start / End Time: 8:00 AM / 9:40 AM
Room: Napoleon Foyer/Common St. Corridor, Sheraton, 3rd Floor
Presentation File: No File Uploaded
Livestock grazing plays a crucial role in influencing the amount of soil organic carbon (SOC) and soil organic nitrogen (SON). Free grazing can also be one of the main factors in severe soil erosion, lowering SOC and SON stocks. The objective of this study was to compare the soil quality of rotationally grazed pastures and the non-grazed forests of Spirit Creek Farm located in northern Georgia. Pastures were managed using no-till planting of fodder crops and intensive rotational grazing with cattle. The 43.4 ha farm has seven soil series (Ultisols and Entisols) composed of mainly sandy and sandy clay loams. Twenty-two sample locations were selected using random sampling methods. A 60cm soil core and 18cm soil profile were collected at each location and soil horizons, color, and texture were described for each profile. Bulk density samples were collected at select locations. Cores were subdivided into 15 samples and SOC and SON concentrations were measured. Both SOC and SON stocks decrease rapidly with depth. No significant difference were found between forest and pasture soil stocks, stratification ratios, or C:N ratios. Initial results indicate that at a depth of 50 cm, SOC stocks were about 47 Mg/ha and SON stocks were about 2.7 Mg/ha. The median SOC stratification ratios were 3.9 for pasture soils and 2.8 for forest soils. The SON stratification ratios were 3.5 for pastures and 2.3 for forests. Pasture soils had C:N ratios (8-35) compared to the forest C:N ratios (12-21).