Fertilizer Nitrogen: Contribution to Nitrate in Surface Water in a Corn Belt Watershed

Kohl, Daniel H.; Shearer, Georgia; Commoner, Barry

doi:10.1126/science.174.4016.1331

Cited by 252 publications

(96 citation statements)

References 6 publications

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“…Biomass accrual has been reported to follow a non-linear increase due to reduced mass transfer velocity, clogged micro channels, detachment by high water velocity, grazing activity and accumulation of toxic substances (SABATER and ADMIRAAL, 2005, and references within). KOHL et al (1971) reported inorganic nitrogen with an isotopic signature of 7.8 ±0.57‰, the upper range for fertilizers, whereas total organic matter was 3.8 ±0.18‰, in agreement with expected values for soil organic nitrogen ( Figure 5). d 15 N-NH 4 + is enriched downstream from the effluent as a result of oxidation, uptake and volatilization; therefore, it is possible that these three processes yield the particular epilithon isotope composition 5700 m downstream from KWTP.…”

Section: Resultssupporting

confidence: 72%

Epilithon isotope composition as an environmental archive in rivers receiving wastewater

Cejudo

Schiff

Aravena

2014

rseau

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Epilithon is a complex community of autotrophic and heterotrophic organisms that includes inert, organic and inorganic material and is attached to the surface of submersed rocks. Water samples collected in the Grand River (southwestern Ontario) in April 2011 showed that ammonium concentrations decreased downstream, whereas nitrate varied, largely dependent on weather conditions (concentrations of both chemical species were higher during winter). Epilithon δ15N-TN downstream from the Kitchener wastewater treatment plant oscillated between 0.4 to 23.2‰, and δ13C-TC around -27‰. The wastewater treatment plant effluent consisted of δ15N-NO3- between 12 and 16‰, with a decreasing trend as it traveled downstream; δ15N-NH4+ became enriched downstream (as high as 31‰). Average values for δ13C-DIC were -10.1‰ and δ13C-DOC -26.8‰. It is proposed that the nitrogen and carbon isotope composition of epilithon could be used as a short- or medium-term environmental archive, as it reflects in-stream processes, such as ammonia oxidation, in a river impacted by treated wastewater. The interpretation provided here was limited due to the ample range of events and potential sources, specifically when the nitrogen isotopic composition of nitrate and ammonium was similar. Epilithon is easily collected, processed and analysed and proved to be valuable tool to describe changes in river and stream geochemistry.

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Section: Resultssupporting

confidence: 72%

Epilithon isotope composition as an environmental archive in rivers receiving wastewater

Cejudo

Schiff

Aravena

2014

rseau

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“…Studies during the 1970s and 1980s largely focused on tracing the fate of fertilizer N in intensive agriculture (e.g. Kohl, Shearer & Commoner, 1971;Meints, Boone & Kurtz, I975fl), and on estimating the fractional contribution of N^-fixation to the N of Na-fixing plants (e.g. Amarger, Mariotti & Mariotti, 1977;Delwiche et al, 1979;Shearer & Kohl, 1986).…”

Section: Discussionmentioning

confidence: 99%

“…The legitimacy of tracing of N inputs and outputs has been a major issue of debate within the field of ^^N abundance studies. The debate started with a contribution by Kohl et al (1971) and was immediately followed by a critical remark from Hauck et al (1972, see also reply from Kohl, Shearer & Commoner, 1972), and later more detailed assessments (Edwards. 1973;Focht.…”

Section: Assessment Of N Balances Of Ecosystemsmentioning

confidence: 99%

“…This discussion concerned the use of fertilizer N in agriculture and the ground and stream water pollution that could result from it. Kohl et al (1971) established a negative correlation between concentration of NOg" and 5'°N of NOg" in stream water in an agricultural area, and used a mixing model to calculate the contribution of fertilizer N to stream water NO3" concentration. As discussed above, 5^"N of fertilizer N is not a conserved tracer within the soil (e.g.…”

Section: Assessment Of N Balances Of Ecosystemsmentioning

confidence: 99%

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Tansley Review No. 95¹⁵N natural abundance in soil‐plant systems

1997

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summary Equilibrium and kinetic isotope fractionations during incomplete reactions result in minute differences in the ratio between the two stable X isotopes, 15N and 14N, in various N pools. In ecosystems such variations (usually expressed in per mil [δ15N] deviations from the standard atmospheric N2) depend on isotopic signatures of inputs and outputs, the input‐output balance, N transformations and their specific isotope effects, and compartmentation of N within the system. Products along a sequence of reactions, e.g. the N mineralization‐N uptake pathway, should, if fractionation factors were equal for the different reactions, become progressively depleted. However, fractionation factors van. For example, because nitrification discriminates against 15N in the substrate more than does N mineralization, NH4+can become isotopically heavier than the organic N from which it is derived. Levels of isotopic enrichment depend dynamically on the stoichiometry of reactions, as well as on specific abiotic and biotic conditions. Thus, the δ15N of a specific N pool is not a constant, and 15N of a N compound added to the system is not a conservative, unchanging tracer. This fact, together with analytical problems of measuring 15N in small and dynamic pools of N in the soil‐plant system, and the complexity of the X cycle itself (for instance the abundance of reversible reactions), limit the possibilities of making inferences based on observations of 15N abundance in one or a few pools of N in a system. Nevertheless, measurements of δ15N might offer the advantage of giving insights into the N cycle without disturbing the system by adding 15N tracer. Such attempts require, however, that the complex factors affecting 15N in plants be taken into account, viz. (i) the source(s) of N (soil, precipitation, NOX, NH3, N2‐fixation), (ii) the depth(s) in soil from which N is taken up, (iii) the form(s) of soil‐N used (organic N, NH4+, NO3−), (iv) influences of mycorrhizal symbioses and fractionations during and after N uptake by plants, and (v) interactions between these factors and plant phenology. Because of this complexity, data on δ15N can only be used alone when certain requirements are met, e.g. when a clearly discrete N source in terms of amount and isotopic signature is studied. For example, it is recommended that N in non‐N2‐fixing species should differ more than 5% from N derived by N2‐fixation, and that several non‐N2‐fixing references are used, when data on δ15N are used to estimate Na‐fixation in poorly described ecosystems. As well as giving information on N source effects, δ15N can give insights into N cycle rates. For example, high levels of N deposition onto previously N‐limited systems leads to increased nitrification, which produces 15N‐enriched NH4 and N‐depleted NO3. As many forest plants prefer NH4−they become enriched in 15N in such circumstances. This change in plant 15N will subsequently also occur in the soil surface horizon after litter‐fall, and might be a useful indicator of N saturation, especially since ...

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“…Measurements of 15 N abundances have been used for over 30 years to identify both point and non-point sources of nitrate. Work by Kreitler ( , 1979, Kreitler and Jones (1975), Shearer et al (1978), Kohl et al (1971), Heaton (1986), Mariotti et al (1988), Korom (1992), and Kendall (1998), and others, has contributed to development and use of the method. Examples of a few studies that illustrate the usefulness of the method include Gormly and Spalding (1979) in Nebraska, Mariotti et al (1988) in France, Mitchell et al (2003) in Canada, and Townsend et al (1994) in Kansas.…”

Section: Introductionmentioning

confidence: 99%

Kansas Case Study Applications of Nitrogen-15 Natural Abundance Method for Identification of Nitrate Sources

Townsend¹,

Young²,

Macko³

2003

Journal of Hazardous Substance Research

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The nitrogen-15 natural abundance method has been a tool for identifying sources of nitrate contami nation in groundwater for almost 30 years. Different ranges of δ 15 N in groundwater are associated with different sources such as fertilizer and animal wastes. However processes such as denitrification, nitrification, and volatilization can alter the δ 15 N signature.Use of this method in Kansas has had mixed results. One case study documented in this paper showed the utility of the method in an area with a sandy unsaturated zone and aquifer, a shallow water table, and an animal waste lagoon. The regional groundwater had an average nitrate-N concentration of 13 mg/L and a δ 15 N signature of +3‰, which indicates a fertilizer source. Effluent leaking from the lagoon (δ 15 N value of +18‰) facilitated denitrification, affecting the regional groundwater, and resulted in a lower nitrate-N concentration of 4 mg/L with a δ 15 N signature of +12 to +20‰ downgradient of the site. The second case study illustrated the utility of the method to identify a variety of sources and the effects of the unsaturated zone on the observed δ 15 N signature in areas with no observable animal waste sources. The presence of carbonate in a loess unsatur ated zone resulted in enriched 15 N, owing to possible volatilization and preferential loss of 14 N.

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Fertilizer Nitrogen: Contribution to Nitrate in Surface Water in a Corn Belt Watershed

Cited by 252 publications

References 6 publications

Epilithon isotope composition as an environmental archive in rivers receiving wastewater

Epilithon isotope composition as an environmental archive in rivers receiving wastewater

Tansley Review No. 95¹⁵N natural abundance in soil‐plant systems

Kansas Case Study Applications of Nitrogen-15 Natural Abundance Method for Identification of Nitrate Sources

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Fertilizer Nitrogen: Contribution to Nitrate in Surface Water in a Corn Belt Watershed

Cited by 252 publications

References 6 publications

Epilithon isotope composition as an environmental archive in rivers receiving wastewater

Epilithon isotope composition as an environmental archive in rivers receiving wastewater

Tansley Review No. 9515N natural abundance in soil‐plant systems

Kansas Case Study Applications of Nitrogen-15 Natural Abundance Method for Identification of Nitrate Sources

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Product

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Tansley Review No. 95¹⁵N natural abundance in soil‐plant systems