Premium
Nitrogen, Sulfur, and Oxygen Isotope Ratios of Animal‐ and Plant‐Based Organic Fertilizers Used in South Korea
Author(s) -
Shin WooJin,
Ryu JongSik,
Mayer Bernhard,
Lee KwangSik,
Kim Insu
Publication year - 2017
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/jeq2017.01.0018
Subject(s) - sulfur , environmental chemistry , nitrogen , environmental science , isotopes of nitrogen , chemistry , oxygen , organic chemistry
Organic fertilizers are increasingly used in agriculture in Asia and elsewhere. Tracer techniques are desirable to distinguish the fate of nutrients added to agroecosystems with organic fertilizers from those contained in synthetic fertilizers. Therefore, we determined the nitrogen, sulfur, and oxygen isotope ratios of nitrogen‐ and sulfur‐bearing compounds in animal‐ and plant‐based organic fertilizers (ABOF and PBOF, respectively) used in South Korea to evaluate whether they are isotopically distinct. The δ 15 N values of total and organic nitrogen for ABOF ranged from +7 to +19‰ and were higher than those of PBOF (generally <+6‰). This suggests that ABOFs have distinct δ 15 N values suitable for tracing these fertilizer compounds in the plant–soil–water system, whereas PBOFs have similar δ 15 N values to synthetic fertilizers. However, δ 18 O values for nitrate (δ 18 O NO3 ) from organic fertilizer samples (<+17.0‰) were consistently lower than those of synthetic nitrate‐containing fertilizers. The δ 34 S values of total sulfur, organic sulfur compounds (e.g., carbon‐bonded sulfur and hydriodic acid‐reducible sulfur), and sulfate for ABOFs yielded wide and overlapping ranges of +0.3 to +6.3, +0.9 to +7.2, and −2.6 to +14.2‰, whereas those for PBOFs varied from −3.4 to +7.7, +1.4 to +9.4, and −4.1 to +12.5‰, respectively, making it challenging to distinguish the fate of sulfur compounds from ABOF and PBOF in the environment using sulfur isotopes. We conclude that the δ 15 N values of ABOFs and the δ 18 O NO3 values of organic fertilizers are distinct from those of synthetic fertilizers and are a promising tool for tracing the fate of nutrients added by organic fertilizers to agroecosystems. Core Ideas Organic fertilizer is a potential contaminant in agroecosystems. Multi‐isotopes of animal‐ and plant‐based organic fertilizers were analyzed. Animal‐based organic fertilizer is discriminated from synthetic fertilizers by δ15N. Animal‐ and plant‐based organic fertilizers showed distinct δ18ONO3. The δ34S of animal‐ and plant‐based organic fertilizer is not reliable as a tracer.