The Science Seminar Series: February 5, 2009
Conservation Agriculture: Past, Present, and Future.
Paul M. White and Thomas L. Potter
USDA-ARS Southeast Watershed Research Unit - Tifton, GA
Place: Powell Hall
Time: 4:00 -5:00pm
Cultivation of crops 10,000 years ago led to settlements and ultimately civilizations in the Fertile Crescent region. Improvements in technology, namely the plow, allowed for more extensive farms and the surplus grain produced formed the first economies. However, over-exploiting the soil as a resource has also had detrimental impacts, including the fall of many civilizations. The industrial revolution resulted in the rapid expansion of farm equipment and the cultivation of the US Midwestern Great Plains. Persistent drought and extensive tillage led to the Dust Bowl of the 1930s. Current issues include sedimentation of the Louisiana coast and formation of a hypoxic dead zone in the Gulf of Mexico. Conservation tillage, encompassing cultivation technologies that reduce soil disturbance, can lead to dramatic improvements in soil and water conservation. Scientists at the USDA-Southeast Watershed Research Unit in Tifton, GA, study the hydrology and agrichemical transport in conventional tillage (Cvt) and conservation tillage (Cst) systems. Studies have demonstrated a two-fold decrease in surface runoff for Cst, as compared to Cvt, with a concomitant two-fold increase in lateral subsurface flow. While reducing sediment transport in Cvt, these changes can have important impacts on pesticide and nutrient fate. In addition to tillage, conservation measures such as cover cropping, companion cropping, and riparian buffer zones provide many benefits including increased biomass for ethanol production, soil carbon sequestration, and agrichemical interception. Future issues in conservation agriculture will focus on reduced water availability and a warming planet.