Relationships among Soil Properties, Nematode Densities, and Soybean Yield in a Long-Term, Double-Crop System in Eastern Arkansas

The economic damage to soybean [Glycine max (L.) Merr.] production in the United States attributed to nematodes has increased in recent years. Understanding how soil properties affect nematodes will help to properly manage agroecosystems to minimize potential nematode damage to soybean crop and the associated economic impact. The objective of this study was to evaluate the relationships between near-surface soil properties and soybean yield and nematode densities across two years (2017 and 2018) in a long-term, wheat (Triticum aestivum L.)-soybean, double-crop production system on a silt-loam soil (Fragiudalfs) in eastern Arkansas. Soybean cyst nematode (SCN; Heterodera glycines Ichinohe) eggs and stage-2 juveniles (J2), lance (Hoplolaimus spp.), lesion (Pratylenchus spp.), spiral (Helicotylenchus spp.), stunt (Tylenchorhynchus spp.), total nematode numbers, and the total genera counts from early in the growing season (July), mid-season (August), and end of the season (October) were generally unrelated with soybean yield. Soybean cyst eggs population density in August was negatively correlated with soil pH (r = -0.92; P ≤ 0.05). Total nematode numbers in July was negatively correlated with silt content (r = -0.23; P ≤ 0.05), soil pH (r = -0.27; P < 0.01), and soil organic matter (SOM, r = -0.24; P ≤ 0.05). Results suggested that soil properties influenced nematode population densities, indicating that nematodes can be at least partially managed and minimized through greater understanding of the variation of select near-surface soil properties in a wheat-soybean, double-crop production system on a silt-loam soil.