Nematode-based soil food web condition in mung bean under semi-arid conditions

In semi-arid regions of Kenya, mung bean plays a significant role as a subsistence and cash crop. Plant-parasitic nematodes that reduce yields are among the biotic constraints affecting the crop. Nematode communities in mung bean monocrop and maize-mung bean intercrop fields in Mbeere South, Embu County, Kenya were assessed. In addition, soil food web indices and metabolic footprints, which can be targeted in enhancement of soil suppressiveness against plant-parasitic nematodes, were also evaluated. Nematode genera from soil samples collected from the monocrop and intercrop fields were identified. The two cropping systems cumulatively had 24 nematode genera belonging to ten functional guilds. Mung bean monocrop had a significantly high number of Scutellonema and Prismatolaimus while the intercrop fields had a greater population of Meloidogyne. There were no significant differences in indices between intercrop and monocrop fields. In both systems, the maturity index of nematodes in cp 2-5 was 2.52 and the channel, basal and enrichment indices were below 50%. Metabolic footprints were similar except the composite footprint which was significantly higher in the maize-mung bean intercrop. Scutellonema and Acrobeles were positively associated with pH while Aphelenchus was positively associated with Carbon. The results of this study can be used in integrated nematode management schemes that enhance the suppressive ability of soil in mung bean cropping systems in both Kenya and other similar regions in Eastern Africa.