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Applied and Environmental Soil Science
Volume 2015, Article ID 275985, 10 pages
Research Article

Sodium Contents in Dairy Cow Urine and Soil Aggregate Sizes Influence the Amount of Nitrogen Lost from Soil

Task Force for Innovation in Life, Resources and Environment Sciences, Research Faculty of Agriculture, Hokkaido University, Kita 9, Nishi 9, Kita-ku, Sapporo, Hokkaido 060-8589, Japan

Received 17 April 2015; Revised 20 October 2015; Accepted 28 October 2015

Academic Editor: Davey Jones

Copyright © 2015 Toru Hamamoto and Yoshitaka Uchida. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Cow urine deposition on pasture soils is a major source of N-related environmental impacts in the dairy farming systems. The urine-N can potentially be lost to the ground water as nitrate () and to the atmosphere as nitrous oxide (N2O). These N-related environmental impacts are possibly related to the sodium (Na+) concentrations in urine. We sampled a pasture soil and separated it into three aggregate size groups (0–3, 3–5, and 5–7 mm). Then, cow urine with variable Na+ concentrations (4.3–6.1 g Na+ L−1) was added to the soil cores. We treated the cores with simulated heavy rains and measured the amounts of calcium (Ca2+), Na+, potassium (K+), and inorganic-N leached from the soils. N2O emission rates were also determined throughout the experimental period. Increasing Na+ concentration in urine decreased the loss of (−20%), after repeatedly applied simulated rain treatments (30 mm × 3), whereas it increased the loss of ammonium (31%) and K+ (19%). For the loss of Ca2+ and the emissions of N2O, the effect of the Na+ concentrations was unclear. Field level studies and studies focusing on the mechanisms behind the changes in nutrient losses are needed.