Effect of Tillage and Cultivar on Plant Population, Sudden Death Syndrome, and Yield of Soybean in Iowa


Sudden death syndrome (SDS) affects soybeans around the world and accounts for millions of tons of yield loss in the United States and Canada, ranking it as one of the top 10 yield-reducing diseases of soybean for 16 years. Managing SDS has been difficult with the lack of effective foliar fungicides and completely resistant cultivars, environmental influences and inconsistent management practices.

The researchers in the study aimed to determine the impact conservation tillage had in relation to SDS. Conservation tillage practices have become common practice to preserve soil moisture and prevent erosion, and has shown results in reducing soybean cyst nematode (SCN) populations in the field. Both SCN and SDS have a linked severity, but SDS also has a positive correlation with the soil moisture content.

The field experiments took place in Iowa in a field with a history of SDS and were evaluated for five consecutive years. Data showed there were differences in root rot severity and foliar disease symptoms across the years among different cultivars, but this was not due to tillage. Although yields were different across the years, researchers write that this was not due to tillage and can be explained by seeding rates and sufficient rainfall. The study confirms using resistant cultivars is the best practice to fight SDS, and that seed treatment, SCN management and diversification in cropping systems can aid in disease resistance. In all, incidences of SDS were not dependent on tillage method, as the incidence of disease was consistent throughout the study. SDS resistant cultivars would make the most impact.  

This study was published in 2019. To view the whole study, click here.

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