Atmospheric sulfur deposition and the sulfur nutrition of crops at an agricultural site in Jiangxi province of China

During the period From November 1998 to October 1999, the air sulfur dioxide (SO2) and sulfate (SO42-) concentrations were measured and rain water was collected on farmland at Yingtan, a typical red soil area in the Jiangxi province of China. Based on hourly meteorological data and surface resistance data from the literature, the dry deposition velocities Of SO2 and SO42- were computed using a three-layer resistance analogy model, and sulfur dry deposition was calculated. The wet deposition was obtained from precipitation amount and sulfur concentrations in rainwater. The average dry deposition velocities Of SO2 and SO42- on farmland were found to be 0.38 +/- 0.16 cm s(-1) (monthly average 0.16-0.55 cm 4 s(-1)) and 0.20 +/- 0.12 cm s(-1) (monthly average 0.15-0.27 cm s(-1)), respectively. The annual total sulfur deposition for the study region is about 103 kg S ha(-1), of which 83% is dry deposition. The uncertainties due to measurement and the dry deposition model are less than 30%. It is also found that atmospheric deposition plays a key role in sulfur circulation within the agrecosystem, accounting for more than 90% of the total sulfur input to farmland.