Rennie, D. A., authorJohns, L. E., authorPaul, E. A., authorAgricultural Institute of Canada, publisher2007-01-032007-01-031976-02Rennie, D. A., E. A. Paul and L. E. Johns, Natural Nitrogen-15 Abundance of Soil and Plant Samples. Canadian Journal of Soil Science 56, no. 1 (February 1976): 43-50. https://dx.doi.org/10.4141/cjss76-006.http://hdl.handle.net/10217/81094Nitrogen isotope analysis of total soil N and soil-derived nitrate for nine selected Chernozemic and Luvisolic Ap horizons showed mean δa15N values based on atmospheric abundance of 8.8. Luvisolic soils were characterized by a relatively low level of the heavier isotope. Isotope enrichment of the total N reached a maximum in the lower B horizon. Subsoil nitrate (180-cm depth) had a δa15N value 1/3 that of the Ap horizon. The δa15N of subsurface soil horizons containing residual fertilizer N were low (−5.2) compared to the surface horizon (7.0). The δa15N of NH4-N in commercial fertilizers is close to that of atmospheric-N whereas the NO3-N has higher values. The data suggest that variations in δ15N abundance between horizons of the same soil, or between different soils, may be of real use in evaluating stresses which have been placed in the nitrogen cycle due to man's activities in the past. Similarly, differences in 15N abundance of soil, legume and air samples may provide an integrated estimation of symbiotic nitrogen fixation under field conditions. More detailed understanding of biological and other processes which control the N isotope concentrations must be obtained before the data reported can be further interpreted.born digitalarticleseng©1976 Agricultural Institute of Canada.Copyright and other restrictions may apply. User is responsible for compliance with all applicable laws. For information about copyright law, please see https://libguides.colostate.edu/copyright.fertilizergrassland soil15Nsoil nitratesNplantsTexthttps://dx.doi.org/10.4141/cjss76-006