| View Larger Image | Pathways and dynamics of ^1^5NO"3^- and ^1^5NH"4^+ applied in a [An article from: Soil Biology and Biochemistry] | Digitalby I. Providoli (Author), H. Bugmann (Author), R. Siegwolf (Author), N Buchmann (Author)
| List Price: | $10.95 | | | Available: | Available for download now |
| | Binding: | Digital | | Publisher: | Elsevier | | Page Count: | 12 Pages | | Publication Date: | July 01, 2006 |
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Product Description
This digital document is a journal article from Soil Biology and Biochemistry, published by Elsevier in 2006. The article is delivered in HTML format and is available in your Amazon.com Media Library immediately after purchase. You can view it with any web browser.Description: To evaluate the pathways and dynamics of inorganic nitrogen (N) deposition in previously N-limited ecosystems, field additions of ^1^5N tracers were conducted in two mountain ecosystems, a forest dominated by Norway spruce (Picea abies) and a nearby meadow, at the Alptal research site in central Switzerland. This site is moderately impacted by N from agricultural and combustion sources, with a bulk atmospheric deposition of 12kgNha^-^1y^-^1 equally divided between NH"4^+ and NO"3^-. Pulses of ^1^5NH"4^+ and ^1^5NO"3^- were applied separately as tracers on plots of 2.25m^2. Several ecosystem pools were sampled at short to longer-term intervals (from a few hours to 1 year), above and belowground biomass (excluding trees), litter layer, soil LF horizon (approx. 5-0cm), A horizon (approx. 0-5cm) and gleyic B horizon (5-20cm). Furthermore, extractable inorganic N, and microbial N pools were analysed in the LF and A horizons. Tracer recovery patterns were quite similar in both ecosystems, with most of the tracer retained in the soil pool. At the short-term (up to 1 week), up to 16% of both tracers remained extractable or entered the microbial biomass. However, up to 30% of the added ^1^5NO"3^- was immobilised just after 1h, and probably chemically bound to soil organic matter. 16% of the NH"4^+ tracer was also immobilised within hours, but it is not clear how much was bound to soil organic matter or fixed between layers of illite-type clay. While the extractable and microbial pools lost ^1^5N over time, a long-term increase in ^1^5N was measured in the roots. Otherwise, differences in recovery a few hours after labelling and 1 year later were surprisingly small. Overall, more NO"3^- tracer than NH"4^+ tracer was recovered in the soil. This was due to a strong aboveground uptake of the deposited NH"4^+ by the ground vegetation, especially by mosses. |
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