Soil chemical properties and their relationship with phytonematode populations inside and outside patches of soybean fields

Phytonematodes cause great losses to agricultural production. The magnitude of their economic impact is directly related to management practices, with the hypothesis that high nematode populations can also be found inside and outside symptomatic patches, and that they correlate with soil properties. This study examined the relationship of soil chemical properties and texture with phytonematode populations inside and outside patches with symptoms of nematode damage in soybean fields. Soil and root samples were collected from commercial fields in Paraguay. A total of 9 nematode parameters and 12 soil variables were evaluated. Statistical analyses were performed initially between nematode parameters and then between nematode parameters and soil properties. Pratylenchus spp. were identified in 95% of root samples. Principal component analysis showed that Pratylenchus spp., nematode eggs, and Meloidogyne spp. were more strongly correlated with roots from inside patches. Helicotylenchus spp., Heterodera glycines, and cysts were more abundant in soil samples, both from inside and outside patches. Pratylenchus spp. was positively correlated with soil sand content and potential acidity and negatively with sum of bases, micronutrients, and potassium, confirming the greater activity of this nematode in low-fertility sandy soils. No significant correlations were found between soil properties and patch type (inside or outside). It concludes that the soil properties interfere in the nematode population, especially in the Pratylenchus. •Pratylenchus was predominant in soybean roots in plants inside the patches.•Pratylenchus correlated positively with Meloidogyne.•Pratylenchus was associated with sandy, acidic, low-fertility soils.•Helicotylenchus, H. glycines, R. reniformis, and S. brachyurus were more abundant in soil.•Nematode populations correlated more strongly with sample type than with patch type.