|
1000
|
Abstract/Summary
|
-
<jats:title>Abstract</jats:title><jats:p>In addition to the removal of excess mineral nitrogen (N) via root uptake, trees in agroforestry systems may mitigate negative effects of high N fertilization of adjacent crops by enhancing complete denitrification of excess mineral N aside from root uptake. Presently, little is known about the potential for NO<jats:sub>3</jats:sub><jats:sup>−</jats:sup> reduction through denitrification (conversion to greenhouse gas N<jats:sub>2</jats:sub>O and subsequently to non-reactive N<jats:sub>2</jats:sub>) in contrasting agroforestry systems: riparian tree buffer versus tree row of an upland alley-cropping system. Our study aimed to (1) quantify gross N<jats:sub>2</jats:sub>O emissions (both N<jats:sub>2</jats:sub>O + N<jats:sub>2</jats:sub> emissions) and gross N<jats:sub>2</jats:sub>O uptake (N<jats:sub>2</jats:sub>O reduction to N<jats:sub>2</jats:sub>), and (2) determine their controlling factors. We employed the <jats:sup>15</jats:sup>N<jats:sub>2</jats:sub>O pool dilution technique to quantify gross N<jats:sub>2</jats:sub>O fluxes from 0 to 5 cm (topsoil) and 40 to 60 cm (subsoil) depths with seasonal field measurements in 2019. The riparian tree buffer exhibited higher topsoil gross N<jats:sub>2</jats:sub>O emissions and uptake than the alley-cropping tree row (<jats:italic>P</jats:italic> < 0.03). Gross N<jats:sub>2</jats:sub>O emissions were regulated by N and carbon (C) availabilities and aeration status rather than denitrification gene abundance. Gross N<jats:sub>2</jats:sub>O uptake was directly linked to available C and <jats:italic>nirK</jats:italic> gene abundance. In the subsoil, gross N<jats:sub>2</jats:sub>O emission and uptake were low in both agroforestry systems, resulting from low mineral N contents possibly due to N uptake by deep tree roots. Nonetheless, the larger available C and soil moisture in the subsoil of riparian tree buffer than in alley-cropping tree row (<jats:italic>P</jats:italic> < 0.05) suggest its large potential for N<jats:sub>2</jats:sub>O uptake whenever NO<jats:sub>3</jats:sub><jats:sup>−</jats:sup> is transported to the subsoil.</jats:p>
|
|
1000
|
Hinweis
|
-
DeepGreen-ID: ababd180428d4f85a6ac8b8abfd77dbe ; metadata provieded by: DeepGreen (https://www.oa-deepgreen.de/api/v1/), LIVIVO search scope life sciences (http://z3950.zbmed.de:6210/livivo), Crossref Unified Resource API (https://api.crossref.org/swagger-ui/index.html), to.science.api (https://frl.publisso.de/), ZDB JSON-API (beta) (https://zeitschriftendatenbank.de/api/), lobid - Dateninfrastruktur für Bibliotheken (https://lobid.org/resources/search)
|
