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Effect of Temperature on Potassium and Sodium Exchange in a Sierra Nevada Riparian Soil
Author(s) -
Blank Robert R.
Publication year - 2010
Publication title -
soil science society of america journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.836
H-Index - 168
eISSN - 1435-0661
pISSN - 0361-5995
DOI - 10.2136/sssaj2009.0159n
Subject(s) - sorption , snowmelt , potassium , sodium , chemistry , soil water , cation exchange capacity , environmental chemistry , zoology , mineralogy , soil science , snow , environmental science , geology , biology , organic chemistry , adsorption , geomorphology
In the course of investigating nutrient availability in a montane meadow ecosystem of the Sierra Nevada range, it was determined that resin availability of Na + and K + was significantly affected by season (winter vs. summer and fall). The underlying mechanism(s) controlling this seasonal effect was investigated in the laboratory. Four replicate A horizon samples of a Typic Humaquept (silty clay texture, kaolinitic mineralogy, 3% organic C, pH 5.10) were saturated with Mg 2+ Using 5‐g subsamples from each replicate, soil was equilibrated for a period of 30 min with 30 mL of a 5.00 mmol solution of Na + and K + at 1, 15, 30, and 45°C. After centrifugation, the supernatant was analyzed for K + , Na + , and Mg 2+ Exchanger sorption characteristics varied significantly with temperature. Overall, K + was preferentially sorbed over Na + , but the proportional sorption of K + decreased significantly at a temperature of 1°C. The temperature dependence of K + and Na + sorption partially explains seasonal differences in availability. Net sorption (K + + Na + − Mg 2+ ) was statistically similar to 0 at temperatures of 15, 30, and 50°C, but significantly increased at 1°C. This increase in cation exchange capacity at low temperature may have special relevance to ecosystems during snowmelt when increased retention of certain cations could occur.