Paper No. 4
Presentation Time: 1:00 PM-5:00 PM
SOIL ORGANIC CARBON IN PASTURE LAND AT 12 APRILS DAIRY IN PELZER, SOUTH CAROLINA
Around the world, agricultural practices have caused severe soil degradation, including erosion and loss of soil organic carbon (SOC). Decreased SOC concentrations are associated with low nutrient concentrations, poor water retention, poor soil structure, and low microbial diversity. In the upstate of South Carolina, poor agricultural management techniques, such as high tillage, have caused a loss of topsoil and a corresponding loss of SOC. The purpose of this particular study was to determine more than twenty years of no-till planting and intensive grazing has increased soil organic carbon at 12 Aprils Dairy in Pelzer, South Carolina. The farm had 21 ha of pasture land on which fodder crops are planted using no-till methods and dairy cows are intensively grazed. A double stratified random sampling method was used to identify 21 sample locations across Cecil Sandy Loam, Appling Sandy Loam, Durham Sandy Loam, and Wehadkee Series ultisols in three different management areas. At each location a 20 cm soil profile and 60 cm soil core were collected. Horizon depths, texture, and color were described for the profiles at each site. Gravimetric loss on ignition (LOI) analysis was used as a proxy for SOC concentrations of the 21 cores. Each core was subdivided into 2 cm samples for the first 10 cm and 5 cm samples for the rest of the core, yielding 291 individual samples. The A-horizon average depth was 6.3 cm and the color was between a dark brown to a dark reddish brown. There were differences in LOI among the same soils series in the different sections of the farm. LOI was the highest in Cecil Sandy Loam in the east section of the farm (and lowest in Cecil Sandy Loam in the west section of the farm. Average 0-10 cm LOI ranged from 4.7% in the Cecil Sandy Loam to 8.9% in the Appling Sandy Loam. One-way ANOVA shows that the median 0-10 cm % LOI for the four soil series is significantly different. Average 20-30 cm LOI ranged from 2.9% in the Cecil Sandy Loam to 5.5% in the Durham Sandy Loam. Most cores showed high LOI in the first few centimeters then the LOI declined with depth. This analysis is limited because only the Appling Sandy loam has a significantly higher % LOI than the Cecil Sandy Loam. For the Piedmont region, the relatively thick and high-LOI A horizon suggests that agroecological methods are effective at restoring soil organic carbon.