Does Elevated Nitrogen and Sulfur Deposition Lead to Net Base Cation Losses in Northern New England Forest Soils?

项目编号：DEB-9615199研究者(S): FERNANDEZ， RUSTAD， KAHL， NORTON机构：缅因大学本研究的目的是继续对缅因州北部贝尔布鲁克的成对流域实验进行处理和监测，重点研究土壤基离子，特别是钙的变化。碱性阳离子耗竭被认为是酸性氮沉降土壤的潜在问题，但很少有数据来自控制良好的长期实验。自1989年秋天以来，贝尔布鲁克流域一直定期用硫酸铵进行处理，据信该地区的氮含量已接近饱和。自1993年以来，碱性阳离子与强酸性阴离子之间的关系发生了变化，随着Al损失的增加，土壤中不稳定的Ca和Mg可能被耗尽。持续的监测将能够检验一系列关于温带森林土壤中阳离子保留和淋失的控制和机制的假设。

ABSTRACT PROPOSAL # : DEB-9615199 INVESTIGATOR(S) : FERNANDEZ, RUSTAD, KAHL, NORTON INSTITUTION: UNIVERSITY OF MAINE The aims of this research are to continue treatment and monitoring of a paired watershed experiment at Bear Brook in northern Maine, with an emphasis on changes in soil base cations, particularly calcium. Base cation depletion is well-recognised as a potential problem in soils that have been subjected to acidic N deposition but few data exist from well-controlled, long-term experiments. The Bear Brook watershed has been periodically treated with ammonium sulfate since the fall of 1989 and is believed to be approaching N saturation. Since 1993 the relationship between base cations and strong acid anions has changed, such that labile Ca and Mg may be depleted in the soils as Al losses increase. Continued monitoring will allow tests of a series of hypotheses about controls and mechanisms of cation retention and leaching in temperate forest soils.