Effects of Pesticide–Fertilizer Combinations on the Rhizosphere Microbiome of Sugarcane: A Preliminary Study

Abstract

A functional pesticide–fertilizer combination is in high demand due to the many potential advantages, including the dual reduction in pesticide and fertilizer inputs, increased crop yield, safe to use, and environmental friendly. To investigate the impact of a pesticide–fertilizer on the soil environment of sugarcane, the effects of clothianidin and/or organic fertilizer treatments on the diversity, structure, and function of the rhizosphere bacterial community were studied using 16S rRNA gene sequencing in 2019 at Guangzhou Sugarcane Research Institute. The bacterial community treated with the pesticide–fertilizer displayed a higher diversity compared with the control treatments (added with pesticide or fertilizer only). The dynamic changes of the bacterial community structure revealed that the pesticide–fertilizer treatment showed a significant variation in the second week. Functional analysis demonstrated that four bacterial genera, including Dyella, Mucilaginibacter, Massilia, and Telmatospirillum, could play an important role in degrading clothianidin and improving soil health. The relative abundance of nitrogen cycle genes showed that the nitrification-related gene pmoA-amoA and denitrification-related genes nirK and norB were increased significantly in the pesticide–fertilizer treatment compared with that of the control treatments. This preliminary study provides a good basis to understand the effect of a pesticide–fertilizer integration on the soil rhizosphere microbiome which would be helpful for the evaluation of its application in the field.