Agronomic Performance and Microbial Diversity of Wheat Following Organic and Synthetic Seed Treatments: A Swiss Field Study

Summary

Crop protection remains a primary research focus, particularly as the world population is increasing, and food security is a top priority worldwide. Several methods of crop protection are incorporated within agriculture, including chemical pesticides. From pre-seeding seed treatment to post-emergence chemicals, pesticides occupy a broad spectrum of different types. Yet, scientists regularly report the dangers of those pesticides to the environment, animals, and humans. In addition, it is becoming evident that pesticides, particularly bactericides and fungicides, have non-specific effects on beneficial soil microbial communities, potentially resulting in a deleterious impact on crops.
We conduct a seven-year field study in collaboration with a network of 20 farmers who aim to minimize the use of pesticides in their agricultural practices, and here report the results of one year. Clean certified seeds have been used for wheat crop cultivation, treated and untreated seeds were used, and the cereals were monitored regarding key yield and sanitary quality parameters. In addition, the rhizosphere bacterial and fungal communities were sequenced and characterized after DNA extraction from soil samples a few weeks after germination. This was achieved through PacBio Revio sequencing of the 16S and ITS amplified regions, respectively.
Our results indicate no difference in emergence, yield, or protein quality between the treated and untreated control groups. In addition, seed treatment did not lead to a higher protection of crops from foliar diseases. The seed treatment did not impact the microbial community composition and alpha diversity. The beta diversity was not significantly different between the two groups, but was driven by soil properties. Our results highlight the potential of omitting seed treatments when using clean certified seeds, and as a result, decreasing the environmental impact of chemical usage in agriculture, as well as saving time and money.