Autor: Yi-Yun Xu, Gerd Deutschmann, Bernard Ludwig
Rok vydání: 2000
Předmět:
Zdroj: Water, Air, and Soil Pollution. 120:89-105
ISSN: 0049-6979
DOI: 10.1023/a:1005281126507
Popis: The acidification of the soil and percolation water at soildepths from 150 to 500 cm was studied at the Solling spruce sitefrom 1991 to 1996. NH4Cl exchangeable cations of the fineearth and bedrock fractions were obtained from different depthsand the soil solution composition was monitored at 150, 200,300, 400 and 500 cm depths using seven suction lysimeters at each depth.In the seepage water collected from 150 and 200 cm depth, pHvalues decreased in the period 1991 to 1996, but no significantchanges were observed in solutions collected below 200 cm depth.Element budgets of Al and Mb (Na, K, Mg, Ca) cationsindicated that buffering by exchange of Al with Mb cationsoccurred mainly in surface 200 cm soil depth. High variabilities in concentrations of SO4 (at 150 cm) andMa (Al, Mn, H, Fe) cations (at 300 and 500 cm) wereobserved. High variabilities in Ma cations could beassigned to one of the lysimeters at each depththat extracted low pH solutions. The amount of exchangeablecations in the fine earth and the bedrock fractions indicatedthat the acidification front (exchangeable Mb cations < 80equivalent percent) had occurred to soil depth of more than 360cm, but the extent of acidification that might have occurred inthe preindustrial period is not known. In both fine earth andbedrock fractions, depthwise changes of exchangeable Ma andMb cations were quite similar, suggesting that rockfractions have contributed to proton buffering not only bysilicate weathering but also by cation exchange.
Databáze: OpenAIRE
Externí odkaz: