Effect of sodium chloride on CO2 evolution,ammonification, and nitrification in a Sassafras sandy loam |
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| Authors: | Ronald W McCormick Duane C Wolf |
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| Institution: | Department of Agronomy, University of Maryland College Park, MD 20742, U.S.A. |
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| Abstract: | Sodium chloride, at rates up to 100 mg g?1, was added to a Sassafras sandy loam amended with finely-ground alfalfa to determine the effect of NaCl on CO2 evolution, ammonification, and nitrification in a 14-week study. A NaCl concentration of 0.25 mg g?1 significantly reduced CO2 evolution by 16% in unamended soil and 5% in alfalfa-amended soil. Increasing NaCl progressively reduced CO2 evolution, with no CO2 evolved from the soil receiving 100 mg NaCl g?1. A 0.50 mg NaCl g?1 rate was required before a significant reduction in decomposition of the alfalfa occurred. The NO?2-N + NO?3-N content of the soil was significantly reduced from 40 to 37 μg g?1 at 0 and 0.25 mg NaCl g?1, respectively in the unamended soil. In the alfalfa amended soil, nitrification was significantly reduced at 5 mg NaCl g?1. At 10 mg NaCl g?1, nitrification was completely inhibited, there being only 6 and 2 μg NO?2-N + NO?3-N g?1 in the alfalfa amended and unamended soil, respectively. In the alfalfa amended soil NH+4-N accumulated from 6 μg g?1 at the 0 NaCl rate to a maximum of 54 μg g?1 with 25 mg NaCl g?1. These higher NH+4-N values resulted in a 0.5 unit increase in the pHw over that of the 0 NaCl rate in the alfalfa amended soil. At NaCl concentrations above 25 mg g?1 there was a reduction in NH+4-N. The addition of alfalfa to the soil helped to alleviate the adverse affects of NaCl on CO2 evolution and nitrification. |
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