Natural 15N abundance of plant and soil inorganic-N as evidence for over-fertilization with compost

Yun, Seok-In; Ro, Hee‐Myong

doi:10.1016/j.soilbio.2009.04.014

Cited by 30 publications

(33 citation statements)

References 27 publications

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“…The main factor driving age-dependent plant δ 15 N signatures is fertilizer N, with type (organic vs. conventional), timing (basal vs. side dressing), and relative rates of application being the most important variables (Yun et al, 2006). Yun et al (2006) and Yun and Ro (2009) found differences of δ 15 N values between the outer, middle, and inner leaves of Chinese cabbage that were related to the source and timing of N fertilization. For example, a side-dress application of urea (−0.7 ) resulted in lower δ 15 N values of inner (newer) leaves (+0.2 ) than outer (older) leaves (+5.5 ), which reflected the isotopic signatures of the basal compost amendment (+16.4 ) (Yun and Ro, 2009).…”

Section: Plant Agementioning

confidence: 99%

Principles and Limitations of Stable Isotopes in Differentiating Organic and Conventional Foodstuffs: 1. Plant Products

Inácio

Chalk

Magalhães

2013

Critical Reviews in Food Science and Nutrition

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Among the lighter elements having two or more stable isotopes (H, C, N, O, S), δ(15)N appears to be the most promising isotopic marker to differentiate plant products from conventional and organic farms. Organic plant products vary within a range of δ(15)N values of +0.3 to +14.6%, while conventional plant products range from negative to positive values, i.e. -4.0 to +8.7%. The main factors affecting δ(15)N signatures of plants are N fertilizers, biological N2 fixation, plant organs and plant age. Correlations between mode of production and δ(13)C (except greenhouse tomatoes warmed with natural gas) or δ(34)S signatures have not been established, and δ(2)H and δ(18)O are unsuitable markers due to the overriding effect of climate on the isotopic composition of plant-available water. Because there is potential overlap between the δ(15)N signatures of organic and conventionally produced plant products, δ(15)N has seldom been used successfully as the sole criterion for differentiation, but when combined with complementary analytical techniques and appropriate statistical tools, the probability of a correct identification increases. The use of organic fertilizers by conventional farmers or the marketing of organic produce as conventional due to market pressures are additional factors confounding correct identification. The robustness of using δ(15)N to differentiate mode of production will depend on the establishment of databases that have been verified for individual plant products.

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Section: Plant Agementioning

confidence: 99%

Principles and Limitations of Stable Isotopes in Differentiating Organic and Conventional Foodstuffs: 1. Plant Products

Inácio

Chalk

Magalhães

2013

Critical Reviews in Food Science and Nutrition

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“…Patterns of foliar and top soil d 15 N depend on the amount of applied fertilizer N (Choi et al 2002;Watzka et al 2006;Yun and Ro 2009). On one hand, net accumulation of 15 N-depleted fertilizer N leaves more distinct imprints in soil.…”

Section: Effects Of Applied N Fertilizer On the D 15 N Of Foliage Andmentioning

confidence: 99%

Nitrogen-15 signals of leaf-litter-soil continuum as a possible indicator of ecosystem nitrogen saturation by forest succession and N loads

Fang

Cheng

et al. 2010

Biogeochemistry

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Understanding forest carbon cycling responses to atmospheric N deposition is critical to evaluating ecosystem N dynamics. The natural abundance of 15 N (d 15 N) has been suggested as an efficient and non-invasive tool to monitor N pools and fluxes. In this study, three successional forests in southern China were treated with four levels of N addition. In each treatment, we measured rates of soil N mineralization, nitrification, N 2 O emission and inorganic N leaching as well as N concentration and d 15 N of leaves, litters and soils. We found that foliar N concentration and d 15 N were higher in the mature broadleaf forest than in the successional pine or mixed forests. Three-year continuous N addition did not change foliar N concentration, but significantly increased foliar d 15 N (p \ 0.05). Also, N addition decreased the d 15 N of top soil in the N-poor pine and mixed forests and significantly increased that of organic and mineral soils in N-rich broadleaf forests (p \ 0.05). In addition, the soil N 2 O emission flux and inorganic N leaching rate increased with increasing N addition and were positively correlated with the 15 N enrichment factor (e p/s ) of forest ecosystems. Our study indicates that d 15 N of leaf, litter and soil integrates various information on plant species, forest stand age, exogenous N input and soil N transformation and loss, which can be used to monitor N availability and N dynamics in forest ecosystems caused by increasing N deposition in the future.

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“…The natural abundance of N isotope ratios ( 15 N/ 14 N ratio, expressed as δ 15 N) of soil inorganic N is a potential tool for studying soil N dynamics, because soil inorganic N has specific isotope compositions affected by δ 15 N of N sources (Yun et al 2006;Yun and Ro 2009) and N isotopic fractionation associated with N transformation processes (Mariotti et al 1981). Variations in δ 15 N of soil inorganic N during the N transformation occur because molecules containing the lighter isotope of N ( 14 N) react faster than those containing the heavier isotope ( 15 N; Kerley and Jarvis 1996).…”

Section: Introductionmentioning

confidence: 99%

Interpreting the temperature-induced response of ammonia oxidizing microorganisms in soil using nitrogen isotope fractionation

Yun

Choi

et al. 2011

J Soils Sediments

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Purpose Although nitrification plays a key role in the fate of soil nitrogen (N) under global warming, little information is available for the nitrifiers' response to changing temperatures. Nitrogen isotope fractionation associated with nitrification can be a proxy of nitrifiers' sensitivity to changing temperature. We hypothesized that the temperature-induced balance between the transport of substrate NH 4 + into the microbial cell (supply) and the intracellular NH 4 + oxidation (consumption) governs the intracellular NH 4 + concentration and then affects nitrification rates and associated isotope fractionations. This study was conducted to understand the microbial response of NH 4 + oxidation to changing temperatures by examining the effect of changing temperature on nitrification rate and apparent isotope fractionation. Materials and methods A batch aerobic incubation was conducted with a sandy loam soil over 150 days at three different soil temperatures: 10, 20, and 30°C. After applying ammonium sulfate, we analyzed the temporal variations in the concentrations and the isotopic compositions of soil inorganic N and calculated nitrification rates and isotope fractionation factors. Results and discussion Net nitrification rate increased with increasing soil temperature, while apparent isotope fractionation factors decreased. The increased net nitrification rate was attributable to both an increase in NH 4 + transport across cell membranes and an increase in intracellular enzymatic activity. Meanwhile, the decreased apparent isotope fractionation suggested that NH 4 + oxidation rate became faster than NH 4 + transport rate, resulting in a decrease in intracellular NH 4 + concentrations.Conclusions Although intracellular NH 4 + transport and oxidation were not directly measured in this study, it is concluded that NH 4 + oxidation is more sensitive to increasing temperature than NH 4 + transport judging from the apparent N isotopic fractionation associated with NH 4 + concentration changes (mainly by nitrification) under different temperature regimes.

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Natural 15N abundance of plant and soil inorganic-N as evidence for over-fertilization with compost

Cited by 30 publications

References 27 publications

Principles and Limitations of Stable Isotopes in Differentiating Organic and Conventional Foodstuffs: 1. Plant Products

Principles and Limitations of Stable Isotopes in Differentiating Organic and Conventional Foodstuffs: 1. Plant Products

Nitrogen-15 signals of leaf-litter-soil continuum as a possible indicator of ecosystem nitrogen saturation by forest succession and N loads

Interpreting the temperature-induced response of ammonia oxidizing microorganisms in soil using nitrogen isotope fractionation

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