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Assessing Soil Nitrogen Availability using Microdialysis‐Derived Diffusive Flux Measurements
Author(s) -
Shaw R.,
Williams A. P.,
Jones D. L.
Publication year - 2014
Publication title -
soil science society of america journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.836
H-Index - 168
eISSN - 1435-0661
pISSN - 0361-5995
DOI - 10.2136/sssaj2014.04.0128n
Subject(s) - microdialysis , soil water , flux (metallurgy) , nitrogen , chemistry , distilled water , soil science , sampling (signal processing) , environmental science , environmental chemistry , soil test , chromatography , biochemistry , extracellular , organic chemistry , filter (signal processing) , computer science , computer vision
Microdialysis‐based soil sampling offers a potential alternative to traditional soil core extractions that better informs about the availability of nitrogen (N) for plant nutrition. This study compared soil N status, as estimated using 0.5 M K 2 SO 4 and distilled water extractions, with microdialysis‐derived diffusive flux measurements in eight grassland soils up an altitudinal gradient. Soil extracts and microdialysis samples were analyzed for plant‐available N: total free amino acids, NH 4 + , and NO 3 − . In terms of the percentage contribution that amino acids, NH 4 + , and NO 3 − made to total plant‐available N, the microdialysis‐derived diffusive flux measurements were most similar to distilled water extractions. However, the relative magnitude of the diffusive flux measurements did not always reflect the pool sizes as estimated by the soil extractions, which suggests that the availability of N to plants, via diffusion, may be decoupled from concentration in these soils. The potential and limitations of microdialysis sampling and the implications of the results for soil N management are discussed.