Atmospheric Sulfur as Related to Acid Precipitation and Soil Fertility
1982
Suarez, E. L. | Jones, U. S.
In experiments conducted to determine the major acidic components of precipitation in the southeastern United States, amounts of sulfur (S) deposited on the soil with rainfall were estimated and relationships between applied sulfur and crop yields in South Carolina were established. Precipitation was collected at three locations from 10 Apr. 1979 to 8 Apr. 1980, at Clemson, S. C., Experiment, Ga., and Franklin, N. C., using a wet/dry collector. Conductivity, pH, and ionic components were determined in the rainfall and particulate matter. Sulfur in the air was collected at Clemson on a 30-d interval in a standard lead peroxide sampler. Soil samples were taken from 15 locations in South Carolina and analyzed for sulfur. It was observed that the average loading concentration of anions in rainwater increased during the spring-summer months and decreased during the fall-winter months. Sulfuric and nitric acids were found to be the major components of acid rainfall. Rainfall and air deposition contributed approximately 10.7 and 1.8 kg/ha of sulfur per year, respectively, at Clemson. Atmospheric deposition from the particulate matter contributed an estimated 3.0 kg/ha of sulfur during the year. Increases in corn grain and silage yields were obtained with the application of 18 kg/ha of sulfur at Darlington, S. C. A relationship between applied sulfur and crop response for the other crops considered could not be established. A need for reevaluating the findings and recommendations for sulfur fertilizers was apparent because of the contribution of atmospheric-deposited sulfur to the soil and plant sulfur supply.
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