The predominant cropping system and management practices play an important role in soil physico-chemical properties and microbiome composition and diversity. This study analyzed the changes in soil fertility and the microbial community in four soybean-based cropping systems over 12 years. Amplification subsequencing techniques were used to compare soil community structures among the systems and identify significant positive and negative fertility factors. Soybean cropping favored the accumulation of OM and the available N, K DTPA Fe, Mn, Zn and Cu contents in soil but not fixed available P. The WS and CS cropping systems were conducive to the fixed available P, but they consumed OM, DTPA K, and Zn. The SC exhibited the lowest soil bacterial and archaeal abundance and diversity but high fungal abundance and diversity. The dominant Proteobacteria in the SC were significantly positively correlated with soil DTPA Fe and Mn. The dominant Actinobacteria were positively correlated with available P, DTPA Cu and Mn. The FS cropping system contained 764 unique bacterial species, 724 unique fungal species and the highest relative abundance of Protista. The FS had high microbial diversity, with high relative abundances of Bacteroidetes and Zygomycota and a significantly lower relative abundance of Actinobacteria. The Bacteroidetes were significantly correlated with available N, OM and DTPA Fe and negatively correlated with available P and DTPA Cu. Zygomycota was negatively correlated with available P and DTPA Cu. In the CS and WS, the soil bacterial abundance and diversity were moderate. The dominant Acidobacteria was significantly negatively correlated with soil DTPA, Fe and Mn. The CS exhibited the lowest fungal abundance and diversity. Furthermore, the relative abundance of Ascomycota was significantly improved in the WS and significantly positively correlated with available P and DTPA Cu. Decreases in the available P, K, DTPA Cu, and Mn of Vertisols greatly affect microbial community structure, and these nutrients regulate bacterial and fungal abundance and diversity. Compared to the SC, the FS, WS, and CS had more balanced soil fertility and microbial stability, but diverse cropping systems are most conducive to soil productivity. These findings are of great relevance for protecting the ecological environment.

In aquatic settings, photodegradation is a significant non-biodegradation method of pesticide degradation. In this investigation, the photodegradation of the herbicide Diquat in aqueous solution was examined under distinct conditions and concentrations. The initial concentration of Diquat and the pH value of the water environment significantly affected the half-life of photodegradation of Diquat, and the opposite was true for different types of water. The photodegradation transformation products (PTPs) formed by the photodegradation of Diquat in an aqueous solution under UV-Vis irradiation were separated and identified using ultra-high-performance liquid chromatography coupled with time-of-fight mass spectrometry (UPLC-QTOF-MS). Based on mass spectral information, four main transition products were identified. Calculations of constituent composition, a comparison of structural analogs, and extant literature all contributed to the structure's determination. The main pathways of photodegradation were found to be oxidation, pyridine ring-opening, cleavage of [C-C] on the piperazine ring, Demethylation reaction and Hydroxylation. These results serve as a foundation for further environmental risk assessment and help explain how Diquat behaves in aquatic environments.

Florpyrauxifen-benzyl is an herbicide that has been developed in recent years. Its degradation mode in paddy soil environments is not clear. In this study, the degradation dynamics in paddy soil and water were studied by ultrahigh-performance liquid chromatography. Microbial degradation was the main degradation pathway. Using third-generation high-throughput sequencing technology, the changes in the soil bacterial community structure were studied. After 30 days of application, compared with the control group (F0), the abundance of Sphingo-monas, Lysobacter, and Flavisolibacter in the recommended and repeated application groups (F1, F5 and F10) increased significantly, and uncultured bacterium and Terrimonas decreased significantly. Compared with the F0 and F1 groups, the species diversity of the F0 and F1 groups showed a significant increase over time. The species diversity of the F5 and F10 groups decreased significantly on Days 5 and 15. On Day 30, the recovery even exceeded that of the control group. Luteimonas and five other genera were positively correlated with herbicide residues, and Pseudolabrys and two other genera were negatively correlated. Repeated application showed a significant effect on the structure of the soil bacterial community, mainly showing a trend of a significant decrease in the initial stage and gradual recovery in the later stage. The results will guide the safe and rational use of florpyrauxifen-benzyl and provide a scientific basis for florpyrauxifen-benzyl dynamic supervision of environmental pollution and protection of black soil in Northeast China.