| dc.description.abstract | Nematodes are a key component of the soil food web and they play an important role in the
provision of ecosystem services. Rice cultivation in Mwea, Kenya involves the intensive use of
fertilizers and pesticides which may affect the complexity of the nematode-based soil food web.
This study examined the nematode diversity and food web structure in irrigated rice fields in
Nyangati and Tebere in Mwea, Kirinyaga County, Kenya. Nematodes were identified up to the
genus level and soil physico-chemical properties were also determined. Aphelenchoides and
Longidorus occurred in significantly greater proportions in Tebere, while in Nyangati there was a
high abundance of Helicotylenchus. Aphelenchoides was positively correlated to soil electrical
conductivity. From additive diversity partitioning of genus richness, the α and β components
contributed 33.7% and 66.3% of the γ diversity, respectively. For Shannon and Simpson diversity
indices, the largest contribution to overall diversity was from α component. Soil food web indices
were similar across the two regions. Channel and basal indices were below 30% while Enrichment
(EI) and Structure (SI) indices were above 50%. There was no variation in metabolic footprints
except for the fungivore footprint which was significantly higher in Tebere. Based on the EI and
SI, the soil food web in paddy rice fields in Mwea was structured and enriched with moderate
disturbance. Due to the high prevalence of economically damaging parasitic nematodes in the rice
fields, appropriate management schemes that enhance specific components of the soil food web
and increase the suppressive ability of soil against plant-parasitic nematodes should be
implemented. | en_US |
