Soilnematode abundance, community composition and biomass were determined in the Fengqiu State Key Agro-Ecological Experimental Station, North China, in order to evaluate the effects of tillage system (conventional tillage and no-tillage) and residuemanagement (0, 50% and 100% wheat residue incorporation/coverage) on the nematodecommunities. Two kinds of indicators (descriptive and evaluative) were categorized. Of the descriptive indicators, residuemanagement had a significant effect on the total nematode abundance, biomass and trophic groups except for bacterivores. Of the evaluative indicators, Shannon diversity (H′), generic richness (GR), nematode channel ratio (NCR) and enrichment index (EI) significantly increased with increasing residue quantity, whereas dominance (λ), basal index (BI) and channel index (CI) exhibited an opposite trend. Significant tillageeffects were observed on the trophic diversity (TD), EI, CI and carbon production (P). The responses of nematodes to tillage and residue were genus-dependent. Canonical correspondence analysis indicated that tillage explained 4.9% and 15.4%, and residuemanagement explained 5.2% and 13.1% of the variations in soilnematode abundance and biomass, respectively. Different metabolic footprint characteristics of the food web were demonstrated graphically by enrichment and structure footprints. The evaluative indicators, such as EI and CI, were sensitive to both tillage and residuemanagement. The descriptive indicators could be used to obtain an intuitive answer to the effect of residuemanagement and the evaluative indicators were more comprehensive for interpreting the structure and function of the soil food web under different tillage and residuemanagement regimes. |
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