Center for the Environment, Plymouth State University, Plymouth, NH 03264, USA.
Proc Natl Acad Sci U S A. 2013 Apr 9;110(15):5999-6003. doi: 10.1073/pnas.1302445110. Epub 2013 Mar 25.
Acid deposition during the 20th century caused widespread depletion of available soil calcium (Ca) throughout much of the industrialized world. To better understand how forest ecosystems respond to changes in a component of acidification stress, an 11.8-ha watershed was amended with wollastonite, a calcium silicate mineral, to restore available soil Ca to preindustrial levels through natural weathering. An unexpected outcome of the Ca amendment was a change in watershed hydrology; annual evapotranspiration increased by 25%, 18%, and 19%, respectively, for the 3 y following treatment before returning to pretreatment levels. During this period, the watershed retained Ca from the wollastonite, indicating a watershed-scale fertilization effect on transpiration. That response is unique in being a measured manipulation of watershed runoff attributable to fertilization, a response of similar magnitude to effects of deforestation. Our results suggest that past and future changes in available soil Ca concentrations have important and previously unrecognized implications for the water cycle.
20 世纪的酸沉降导致工业化世界大部分地区的土壤有效钙大量枯竭。为了更好地了解森林生态系统对酸化胁迫因素变化的响应，一个 11.8 公顷的流域用硅灰石（一种硅酸钙矿物质）进行了改良，通过自然风化将土壤有效钙恢复到工业化前的水平。钙改良的一个意外结果是流域水文发生了变化；处理后 3 年内，年蒸散量分别增加了 25%、18%和 19%，然后才恢复到预处理水平。在此期间，流域从硅灰石中截留了钙，表明蒸散对流域施肥具有流域尺度的影响。这种反应是独特的，是对流域径流量的可测量的施肥管理归因于施肥的响应，其影响与森林砍伐的影响相似。我们的研究结果表明，过去和未来土壤有效钙浓度的变化对水循环具有重要的、以前未被认识到的影响。
