Biochar amendment alters degradation of three pesticides in broccoli, pakchoi, and shifted bacterial commnuity in soil under greenhouse conditions

Abstract Graphical abstract Abstract A 28-day pesticide degradation experiment was conducted on broccoli (Brassica oleracea L. var. italica Planch) and pakchoi (Brassica chinensis L.) with three pesticides (chlorantraniliprole (CAP), haloxyfop-etotyl (HPM), and indoxacarb (IXB)) to explore biochar effect on pesticides environmental fate and rhizosphere soil diversity. Rice straw biochar (RB) was applied to soil with 25 t·ha−1 dosage under greenhouse conditions, and its effects on the degradation of three pesticides and soil were investigated one by one. Overall, RB application effectively facilitated CAP and HPM degradation in broccoli by 13.5-39.4% and in broccoli soil by 23.8-74.1%. While for RB application retarted CAP, HPM and IXB degradation in pakchoi by 0-57.17% and retarted CAP degradationin in pakchoi by 37.32-43.4%. The results showed that RB application effect on pesticide degradation in crops and soil was related to biochar properities, pesticide solubility, plant growth status, and soil characteristics. Rhizosphere soil microorganisms were investigated at the same time and the result showed that biochar application may be valuable in altering the bacterial richness and diversity. The effect of biochar application on pesticide residues in crops and soil was influenced by the growth status of crops mostly, and the next was pesticides characteristics. This study suggested that biochar application in soil may be effect to reduce pesticide non-point source pollution, especially for pesticide with high solubility and may shift soil microorganisms.