New p-coumaric acid formulation in sustainable pest management; impact on soil bacterial diversity and N-cycle

Abstract

Synthetic pesticides can pose a serious threat to the soil environment and are responsible for several adverse health effects in humans. The study aimed to assess the impact of a new formulation based on p-coumaric acid (p-CA) on the abundance, diversity, and structure of bacterial communities with the use of next-generation sequencing (NGS) of the 16S rRNA gene and quantitative PCR (qPCR). The commercial fungicide Porter 250 EC and a new formulation with p-CA as a natural bioactive substance were applied to arable soil in laboratory conditions. Neither difenoconazole nor the new plant protection product (PPP) (final concentration 0.03 μmol/g wet mass and 9.1 μmol/g wet mass, respectively) showed any significant effect (P < 0.05) on the bacterial biodiversity indices, nor did they show any effect on the abundance of bacteria associated with the N-cycle. However, detailed analyses revealed that both formulations significantly altered the structure of soil bacterial communities (P < 0.01). More bacterial phylotypes (50 versus 29) changed their abundance in soil treated with p-CA based formulation compared to Porter 250 EC after two weeks of treatment. After four weeks the changes caused by the new formulation were substantially less numerous (17 versus 50) than after two weeks which may favor the restoration of bacterial homeostasis at the end of the exposure period. Based on the results we can conclude that the new p-CA based formulation constitutes a promising product to be used in sustainable agriculture.