Potential impact of conservation tillage on conserving water resources in Georgia
2007
Reduced tillage and surface residue increases infiltration, soil water content, and plant available water, while at the same time decreasing runoff and sedimentation. However, there is a general lack of knowledge and appreciation regarding the impact conservation tillage has on sustainable water resources. The objective of this study was to estimate water savings as a result of conservation tillage adoption in Georgia. Total acreages by crop (cotton, corn, and peanut) and tillage (conventional and conservation) were obtained via the Conservation Technology Information Center for the 2004 growing season. Rainfall simulation studies conducted over row-cropped lands in conventional and conservation tillage were obtained for soils in the Coastal Plain and Piedmont physiographies. Data were integrated within a geographical information system. In 2004, cotton, corn, and peanuts represented 85% of row crop production in Georgia, with nearly 90% of the acreage in the Coastal Plain. Conservation tillage systems are currently in place on approximately 30% of those acreages, primarily in the form of strip tillage. Results from rainfall simulation studies indicate that conservation tillage can reduce runoff and increase infiltration in these systems by 29% to 46%. Extrapolating these results to the state, conservation tillage reduced estimated statewide, irrigated water requirements from 4% to 14%. Increasing conservation tillage to 40% in intensively row-cropped counties where conservation tillage adoption rates were less than the national average (40%) increased estimated water savings by an additional 1% to 6%.
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