Land use and hydrologic flowpaths interact to affect dissolved organic matter and nitrate dynamics Toosi, Ehsan Schmidt, John Castellano, Michael Castellano, Michael
dc.contributor.department Agronomy 2018-02-18T21:47:31.000 2020-06-29T23:03:20Z 2020-06-29T23:03:20Z 2014-04-23
dc.description.abstract <p>The transport and transformation of dissolved organic matter (DOM) and dissolved inorganic nitrogen (DIN) through the soil profile impact down-gradient ecosystems and are increasingly recognized as important factors affecting the balance between accumulation and mineralization of subsoil organic matter. Using zero tension and tension lysimeters at three soil depths (20, 40, 60 cm) in paired forest and maize/soybean land uses, we compared dissolved organic C (DOC), dissolved organic N (DON) and DIN concentrations as well as DOM properties including hydrophilic-C (HPI-C), UV absorption (SUVA<sub>254</sub>), humification index and C/N ratio. Soil moisture data collected at lysimeter locations suggest zero tension lysimeters sampled relatively rapid hydrologic flowpaths that included downward saturated flow through the soil matrix and/or rapid macropore flow that is not in equilibrium with bulk soil solution whereas tension lysimeters sampled relatively immobile soil matrix solution during unsaturated conditions. The effect of land use on DOC and DON concentrations was largely limited to the most shallow (20 cm) sampling depth where DOC concentrations were greater in the forest (only zero tension lysimeters) and DON concentrations were greater in the cropland (both lysimeter types). In contrast to DOC and DON <em>concentrations</em>, the effect of land use on DOM <em>properties</em> persisted to the deepest sampling depth (60 cm), suggesting that DOM in the cropland was more decomposed regardless of lysimeter type. DOC concentrations and DOM properties differed between lysimeter types only in the forest at 20 cm where soil solutions collected with zero tension lysimeters had greater DOC concentrations, greater SUVA<sub>254</sub>, greater humification index and lower HPI-C. Our data highlight the importance of considering DOM quality in addition to DOC quantity, and indicate long-term cultivation reduced the delivery of relatively less decomposed DOM to all soil depths.</p>
dc.description.comments <p>This article is published as Toosi ER, Schmidt JP, Castellano MJ. 2014. Land use and hydrologic flowpaths interact to affect dissolved organic matter and nitrate dynamics. <strong><em>Biogeochemistry</em></strong>, doi: <a href="" target="_blank">10.1007/s10533-014-9983-0</a>. Posted with permission.</p>
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dc.identifier.articleid 1194
dc.identifier.contextkey 10649002
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dc.identifier.submissionpath agron_pubs/199
dc.language.iso en
dc.source.bitstream archive/|||Fri Jan 14 22:00:55 UTC 2022
dc.source.uri 10.1007/s10533-014-9983-0
dc.subject.disciplines Agriculture
dc.title Land use and hydrologic flowpaths interact to affect dissolved organic matter and nitrate dynamics
dc.type article
dc.type.genre article
dspace.entity.type Publication
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