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A Comparison of the Effectiveness of 15 N‐Enriched vs. Unenriched Fertilizer Nitrogen as a Tracer in Laboratory Experiments
Author(s) -
Feigin Amos,
Vaughan William M.,
Smith Ray,
Kohl Daniel H.,
Shearer Georgia,
Commoner Barry
Publication year - 1974
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/jeq1974.00472425000300040027x
Subject(s) - fertilizer , nitrogen , nitrate , soil water , chemistry , tracer , incubation , zoology , abundance (ecology) , agronomy , environmental chemistry , environmental science , soil science , ecology , biology , biochemistry , organic chemistry , nuclear physics , physics
The experiments reported in this paper were designed (i) to determine whether it is possible to detect the presence of fertilizer nitrogen in nitrate produced by four central Illinois soils during laboratory incubation by using variations in the natural abundance of 15 N, (ii) to use such variations to estimate the fractional contribution of fertilizer nitrogen to the nitrate produced, and (iii) to compare these estimates with those based on the use of fertilizer nitrogen which was artificially enriched with 15 N. The mean δ 15 N per mill excess) value of nitrate produced during incubation of the soils which had received unlabeled (NH 4 ) 2 SO 4 was significantly lower in 11 out of 12 experiments compared with that produced by unfertilized soils. As expected, estimates of percent fertilizer derived nitrogen based on variations in natural abundance of 15 N were less precise than those based on the use of (NH 4 ) 2 SO 4 artificially enriched with 15 N. The use of natural variations in 15 N abundance to compute the percent fertilizer derived nitrate resulted in a lower estimate than the estimate based on 15 N enriched material in seven experiments. This underestimation appeared to be related to the so called “priming effect” and/or the exchange of fertilizer and soil nitrogen.