Influence of soil physicochemical properties on plant-parasitic nematode assemblages in contrasting agricultural soils

This study investigates the spatial variation of plant-parasitic nematode (PPN) communities and their association with soil physicochemical properties across contrasting agricultural soils in three major regions of New Zealand: Waikato, Canterbury, and Manawatū-Whanganui. PPN assemblages were dominated by root-lesion and spiral nematodes, with Canterbury showing the highest Shannon and Simpson diversity and species richness, followed by Waikato and Manawatū-Whanganui. Non-metric multidimensional scaling (NMDS) and hierarchical clustering revealed partial regional separation of nematode communities, and multivariate analyses confirmed significant regional variation ( p < 0.05). Spearman correlations indicated weak to moderate associations between PPNs, diversity, and soil properties: lesion nematodes were negatively correlated with pH and moisture, root-knot nematodes were weakly positively correlated with Shannon diversity and richness, and Tylenchus showed weak positive associations with diversity and C/N ratio. Diversity increased with silt but decreased with sand, phosphorus, carbon, and nitrogen. Additionally, canonical correspondence analysis (CCA) demonstrated that soil parameters collectively explained 20–25% of the variation in PPN community structure, with significant influences from phosphorus, pH, sand, clay, C/N ratio, and moisture content. Key associations, as indicated by their proximity to the corresponding environmental vectors, were observed between lesion nematodes and clay, spiral nematodes and moisture content, and ring nematodes and soil moisture and sand%. These findings provide the first detailed account of PPN ecology in New Zealand, highlighting the significant influence of regional soil characteristics on the composition of PPN communities. While valuable baseline data are presented, further research is recommended to explore seasonal dynamics, long-term trends, and the impact of different agronomic practices, informing more effective, region-specific PPN management strategies. • First ecological work of PPN communities in New Zealand. • PPN population structures differ notably between regions. • Soil P, pH, sand, clay, C/N ratio, and soil moisture content influence PPN distribution.