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The Effects of Throughfall Manipulation on Soil Leaching in a Deciduous Forest
Author(s) -
Johnson D.W.,
Hanson P.J.,
Todd D.E.
Publication year - 2002
Publication title -
journal of environmental quality
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.888
H-Index - 171
eISSN - 1537-2537
pISSN - 0047-2425
DOI - 10.2134/jeq2002.2040
Subject(s) - throughfall , lysimeter , leaching (pedology) , chemistry , soil horizon , acid rain , deciduous , environmental chemistry , soil water , precipitation , soil acidification , forest floor , soil ph , soil science , environmental science , ecology , physics , organic chemistry , biology , meteorology
ABSTRACT The effects of changing precipitation on soil leaching in a deciduous forest were examined by experimentally manipulating throughfall fluxes in the field. In addition to an ambient treatment (AMB), throughfall fluxes were reduced by 33% (DRY treatment) and increased by 33% (WET treatment) using a system of rain gutters and sprinklers on Walker Branch Watershed, Tennessee. Soil leaching was measured with resin lysimeters in the O horizons and with ceramic cup lysimeters in the E (25 cm) and Bt (70 cm) horizons. Large and statistically significant treatment effects on N fluxes were found in the O horizons (lower N fluxes in the DRY and higher N fluxes in the WET treatment). Together with the greater O horizon N content observed in the DRY treatment, this suggested that N was being immobilized at a greater rate in the DRY treatment than in the AMB or WET treatments. No statistically significant treatment effects on soil solution were found in the E horizons with the exception of (Ca 2+ + Mg 2+ ) to K + ratio. Statistically significant treatment effects on electrical conductivity (EC), pH, Ca 2+ , Mg 2+ , K + , Na + , SO 2− 4 , and Cl − were found in the Bt horizons due to differences between the DRY and other treatments. Despite this, calculated fluxes of Ca 2+ , Mg 2+ , K + , Na + , SO 2− 4 , and Cl − were lowest in the DRY treatment. These results suggest that lower precipitation will cause temporary N immobilization in litter and long‐term enrichment in soil base cations whereas increased precipitation will cause long‐term depletion of soil base cations.