<?xml version='1.0' encoding='utf-8'?>
<oai_dc:dc xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:oai_dc="http://www.openarchives.org/OAI/2.0/oai_dc/" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.openarchives.org/OAI/2.0/oai_dc/ http://www.openarchives.org/OAI/2.0/oai_dc.xsd">
  <dc:creator>L.J. Puckett</dc:creator>
  <dc:date>1990</dc:date>
  <dc:description>&lt;p&gt;&lt;span&gt;Estimates of external and internal sources of ions in net througfall deposition were derived for a deciduous and coniferous canopy by use of multiple regression. The external source component appears to be dominated by dry deposition of Ca&lt;/span&gt;&lt;sup&gt;2+&lt;/sup&gt;&lt;span&gt;, SO&lt;/span&gt;&lt;sub&gt;2&lt;/sub&gt;&lt;span&gt;&amp;nbsp;and NO&lt;/span&gt;&lt;sub&gt;3&lt;/sub&gt;&lt;sup&gt;−&lt;/sup&gt;&lt;span&gt;&amp;nbsp;during dormant and growing seasons for the two canopy types. Increases in the leaching rates of K&lt;/span&gt;&lt;sup&gt;+&lt;/sup&gt;&lt;span&gt;&amp;nbsp;and Mg&lt;/span&gt;&lt;sup&gt;2+&lt;/sup&gt;&lt;span&gt;&amp;nbsp;during the growing season reflect the presence of leaves in the deciduous canopy and increased physiological activity in both canopies. Internal leaching rates for SO&lt;/span&gt;&lt;sub&gt;4&lt;/sub&gt;&lt;sup&gt;2−&lt;/sup&gt;&lt;span&gt;&amp;nbsp;doubled during the growing season presumably caused by increased physiological activity and uptake of SO&lt;/span&gt;&lt;sub&gt;2&lt;/sub&gt;&lt;span&gt;&amp;nbsp;through stomates. Net deposition of SO&lt;/span&gt;&lt;sub&gt;4&lt;/sub&gt;&lt;sup&gt;2−&lt;/sup&gt;&lt;span&gt;&amp;nbsp;in throughfall during the growing season appears highly dependent on stomatal uptake of SO&lt;/span&gt;&lt;sub&gt;2&lt;/sub&gt;&lt;span&gt;. Estimates of SO&lt;/span&gt;&lt;sub&gt;2&lt;/sub&gt;&lt;span&gt;&amp;nbsp;deposition velocities were 0.06 cm s&lt;/span&gt;&lt;sup&gt;−1&lt;/sup&gt;&lt;span&gt;&amp;nbsp;and 0.13 cm s&lt;/span&gt;&lt;sup&gt;−1&lt;/sup&gt;&lt;span&gt;&amp;nbsp;for the deciduous and coniferous canopies, respectively, during the dormant seasons, and 0.30 cm s&lt;/span&gt;&lt;sup&gt;−1&lt;/sup&gt;&lt;span&gt;&amp;nbsp;and 0.43 cm s&lt;/span&gt;&lt;sup&gt;−1&lt;/sup&gt;&lt;span&gt;&amp;nbsp;for the deciduous and coniferous canopies, respectively, during the growing season. For the ions of major interest with respect to ecosystem effects, namely H&lt;/span&gt;&lt;sup&gt;+&lt;/sup&gt;&lt;span&gt;, NO&lt;/span&gt;&lt;sub&gt;3&lt;/sub&gt;&lt;sup&gt;−&lt;/sup&gt;&lt;span&gt;&amp;nbsp;and SO&lt;/span&gt;&lt;sub&gt;4&lt;/sub&gt;&lt;sup&gt;2−&lt;/sup&gt;&lt;span&gt;, precipitation inputs generally outweighed estimates of dry deposition input. However, net throughfall deposition of NO&lt;/span&gt;&lt;sub&gt;3&lt;/sub&gt;&lt;sup&gt;−&lt;/sup&gt;&lt;span&gt;&amp;nbsp;and SO&lt;/span&gt;&lt;sub&gt;4&lt;/sub&gt;&lt;sup&gt;2−&lt;/sup&gt;&lt;span&gt;&amp;nbsp;accounted for 20–47 and 34–50 per cent, respectively, of total deposition of those ions. Error estimates of ion sources were at least 50–100 per cent and the method is subject to several assumptions and limitations.&lt;/span&gt;&lt;/p&gt;</dc:description>
  <dc:format>application/pdf</dc:format>
  <dc:identifier>10.1016/0960-1686(90)90009-C</dc:identifier>
  <dc:language>en</dc:language>
  <dc:publisher>Elsevier</dc:publisher>
  <dc:title>Estimates of ion sources in deciduous and coniferous throughfall</dc:title>
  <dc:type>article</dc:type>
</oai_dc:dc>