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| Titel |
Influence of biotic and abiotic processes on the immobilization and distribution of applied N in fertilized paddy soils |
| VerfasserIn |
Maria Alexandra Cucu, Daniel Said-Pullicino, Federica Divotti, Michele Chierotti, Luisella Celi |
| Konferenz |
EGU General Assembly 2013
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 15 (2013) |
| Datensatznummer |
250072386
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| Zusammenfassung |
| Poor fertilizer-N use efficiency is characteristic of irrigated rice agro-ecosystems with
recoveries ranging from 40–60% of applied N. This has been largely attributed to a greater
degree of N immobilization and important losses of applied fertilizer-N as a consequence of
the alternating soil redox conditions to which paddy soils are subjected during the cropping
season. This work aims at providing a better understanding of biotic and abiotic processes
controlling N immobilization in these soils, necessary to improve fertilizer-N management
and the sustainability of rice agro-ecosystems.
To evaluate the relative contribution of biotic and abiotic processes affecting N
immobilization, a typical paddy soil was incubated for 30 days under (i) sterile or non-sterile
anoxic conditions, (ii) with or without the addition of rice straw. Gamma radiation was
utilized to sterilize the soils without affecting soil properties, while anaerobic conditions were
ensured by incubating the soils under water saturated conditions. Enriched ammonium-15N
was applied to evaluate the immobilization of fertilizer-N while the distribution of
immobilized N among soil fractions was assessed by combining aggregate size and organic
matter density fractionation.
Results have evidenced a rapid immobilization of ~40% of applied N in both sterilized
and non-sterilized treatments. Most of this N (~87%) was associated with the finest soil
fractions ( |
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