The global application of neonicotinoids (NEOs) has precipitated pervasive contamination of agricultural matrices, with China’s staple crop lands representing critical exposure hotspots. The occurrence and ecological risks of ten NEOs in the field soils of three major crops (i.e., rice, wheat and corn) in China were investigated in the present study. Employing an optimized UPLC-MS/MS method (LOQ = 0.01–1.7 ng/g, RSD < 12.21%), ten NEOs across 69 representative field soils (rice: 23, corn: 18, wheat: 28) were quantified. It was found that the detection frequency (DF) of the NEOs was 100% in the soil. The DFs of NEOs in the soil followed the rule: imidacloprid (IMI, 100%) > thiamethoxam (TMX, 88.4%) > clothianidin (CLO, 87.0%) > acetamiprid (ACE, 46.4%) > dinotefuran (DIN, 7.2%) > nitenpyram (NIT, 1.4%). Mean total detected NEOs concentrations exhibited crop-dependent type: wheat (1.77–214.55 ng/g) > corn (0.79–97.53 ng/g) > rice (0.75–72.97 ng/g). The IMI, CLO and TMX triad constituted over 90% of the total contribution of detected NEOs. In addition, CLO and TMX in the rice soils, IMI, CLO and TMX in the corn soils and IMI, CLO and TMX in the wheat soils had medium ecological risks. Therefore, it is particularly important for agricultural ecological protection to strengthen monitoring and take effective measures to protect agricultural ecology.

This study developed a UHPLC-MS/MS method combined with a modified QuEChERS pretreatment technique to simultaneously determine diflufenican, pyroxasulfone, and their metabolites (M-1, M-3, M-25) in wheat grain and straw. The method exhibited good linearity within the concentration range of 0.0001–0.1 mg/L (r > 0.996), with a limit of quantification of 0.002 mg/kg. At three spiked levels, the average recoveries of the target analytes ranged from 82.0% to 110.1%, with relative standard deviations ≤ 13.9%. All analytes remained stable in both grain and straw matrices when stored at ≤−18 °C for 12 months. Field trials demonstrated that diflufenican residues in grains were all below 0.002 mg/kg, while residues in straw ranged from 0.002 to 0.018 mg/kg. The total residues of pyroxasulfone and its metabolites in grains ranged from 0.010 to 0.019 mg/kg, and in straw from 0.026 to 0.357 mg/kg. Dietary risk assessment results showed that the risk quotients for diflufenican and pyroxasulfone were 0.10% and 0.27%, respectively, both far below the 100% safety threshold. Based on the residue data and risk assessment results, it is recommended that the maximum residue limits for pyroxasulfone in wheat in China be set at 0.03 mg/kg for grains and 0.6 mg/kg for straw. These proposed values align with international standards while also accommodating the practical needs of domestic agricultural production and regulatory oversight.