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| Titel |
Abundance and diversity of total and nitrifying prokaryotes as influenced by biochemical quality of organic inputs combined with mineral nitrogen |
| VerfasserIn |
Esther Muema, Bernard Vanlauwe, Carolin Röhl, Georg Cadisch, Frank Rasche |
| Konferenz |
EGU General Assembly 2014
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 16 (2014) |
| Datensatznummer |
250089419
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| Publikation (Nr.) |
 EGU/EGU2014-3621.pdf |
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| Zusammenfassung |
| Ammonia-oxidizing bacteria and archaea (AOB, AOA) co-exist in soil, but they respond
differently to distinct fertilization strategies in agricultural soils. Accordingly, effects of
organic inputs and combination with mineral nitrogen (N) on AOB and AOA remain poorly
understood. The aim of this study was to compare soil amendment with contrasting quality of
organic inputs (i.e., high quality Tithonia diversifolia (TD; C/N ratio: 13, Lignin: 8.9 %;
Polyphenols: 1.7 %), intermediate quality Calliandra calothyrsus (CC; 13; 13; 9.4) and
low quality Zea mays (ZM; 59; 5.4; 1.2)), and combination with mineral N on the
abundance (i.e., DNA-based gene quantification) and community structure (i.e., T-RFLP
analysis) of total bacterial and archaea (16S rRNA gene), as well as AOB and AOA
(targeting the amoA gene) communities in a Humic Nitisol. Soils (0-15 cm depth) were
sampled prior to the onset of the rainy season in March 2012 in a 10 years old field
experiment established in the central highlands of Kenya in 2002. Since the start of the
experiment, organic inputs were applied annually at a rate of 4 Mg C ha-1 and mineral N
twice a year as calcium ammonium nitrate (5Ca(NO3)2NH4NO3) at a rate of 120
kg N ha-1 growing season-1. Quality of organic inputs posed only a significant
effect on the AOB community structure between TD versus ZM and CC versus ZM.
Moreover, TD significantly increased the size of AOB over ZM input, while higher
abundances for total bacteria, total archaea and AOA were measured in ZM and TD
over CC. This was explained by high and available N in TD, but low lignin and
polyphenol contents in TD and ZM as opposed to CC. AOB responded sensitively
(i.e., complete community structure separation) to mineral N, specifically when
combined with low quality ZM. Hence, AOB community was specifically responsive
to quality of organic inputs and combination of low organic input with mineral
N over AOA and total prokaryotic communities in the studied soil. The results
presented were however, generated on one occasion soil sampling representing the
effect of continuous organic and inorganic fertilizer application for ten years. We
therefore recommend for prospective research, further investigations to rule out the
temporal (short-term) variations of microbial decomposer dynamics at different
crops growth stages during a cropping season as well as comparing different soil
types. |
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