Soybean Cyst Nematode Reproduction and Soybean Biomass: The Legacy of Soil Cropping Histories

The soybean cyst nematode (SCN), Heterodera glycines, represents the most yield-limiting pathogen of soybean in North America. Although crop rotation serves as a common SCN management strategy, the influence of previous cropping history on nematode establishment in previously non-infested (naïve) soils remains poorly understood. This study examined the impact of various cropping histories on SCN establishment of naïve soils. We hypothesized that recent soybean cropping would leave a biochemical legacy, particularly through root exudates, that enhances SCN abundance by promoting egg hatching and infectivity, as measured by final egg counts after one full SCN life cycle. To test this, we conducted a series of greenhouse experiments using soil from fields with different cropping histories and no SCN infestation, including continuous soybean, rotational soybean, horticultural cropping, prairie, Kernza, and fallow fields. In general, cropping history had no impact on final SCN abundance. Similarly, susceptible soybean varieties did not interact with cropping history to influence SCN abundance. Cropping history also failed to consistently affect plant biomass after infestation. In three experiments, however, SCN infestation was associated with increased soybean biomass, potentially reflecting compensatory growth responses. These findings suggest that SCN establishment is not significantly influenced by recent cropping history in naïve soils. Further research should target the mechanism underlying compensatory growth and their implications for soybean yield and nematode management strategies.