The impact of microplastics (MPs) as emerging pollutants on plant heavy metal toxicity has been extensively reported in vegetable–soil systems over recent years. However, little attention has been given to cultivar variations between degradable and non-degradable MPs. This study investigated the effects of degradable polylactic acid (PLA) and nondegradable polypropylene (PP) MPs on plant growth and biomarker (malonaldehyde (MDA) and antioxidant enzymes) performance in Cd-contaminated arable soil. The results show that both types of MPs significantly impacted plant biomass and biomarker contents across all three Cd levels. The degree of impact was significantly sensitive to both the type and dose of MPs, as they reduced the soil pH and cation exchange capacity (CEC) while increasing soil dissolved organic carbon (DOC), microbial biomass carbon, and nitrogen. PP exhibited greater root growth inhibition and phytotoxicity at higher doses of 1% and 5% compared to PLA. Specifically, the highest MDA contents were 1.44 and 2.20 mmol mg⁻¹ protein for shoots and roots, respectively, in the 5% PLA treatment under a 10.1 mg kg⁻¹ Cd level, which were 1.22 and 1.18 times higher than those in corresponding treatments of 5% PP. Overall, PLA had less significant effects on plant phytotoxicity, Cd availability, and soil properties compared to PP. Regression pathway analysis indicated that MPs increased shoot Cd uptake by altering both soil physical–chemical and microbial characteristics. Among the soil variables, pH, CEC, and Cd bioavailability were found to play vital roles. Yet, no single variable acts alone in the mechanism for plant Cd uptake. PLAs are suggested to replace conventional non-biodegradable plastics to control environmental MP pollution, particularly in agricultural systems with higher Cd contamination. However, the long-term effects of the by-products generated during the biodegradation process require further investigation.

The damage excessive neodymium (Nd) causes to animals and plants should not be underestimated. However, there is little research on the impact of pH and associated ions on the toxicity of Nd. Here, a biotic ligand model (BLM) was expanded to predict the effects of pH and chief anions on the toxic impact of Nd on wheat root elongation in a simulated soil solution. The results suggested that Nd³⁺ and NdOH²⁺ were the major ions causing phytotoxicity to wheat roots at pH values of 4.5-7.0. The Nd toxicity decreased as the activities of H⁺, Ca²⁺, and Mg²⁺ increased but not when the activities of K⁺ and Na⁺ increased. The results indicated that H⁺, Ca²⁺, and Mg²⁺ competed with Nd for binding sites. An extended BLM was developed to consider the effects of pH, H⁺, Ca²⁺, and Mg²⁺, and the following stability constants were obtained: logK_NdBL = 2.51, logK_NdOHBL = 3.90, logK_HBL = 4.01, logK_CaBL = 2.43, and logK_MgBL = 2.70. The results demonstrated that the BLM could predict the Nd toxicity well while considering the competition of H⁺, Ca²⁺, Mg²⁺ and the toxic species Nd³⁺ and NdOH²⁺ for binding sites.

This study investigated the effects of fully biodegradable poly(butylene adipate-co-terephthalate) (PBAT) mulch films with different thicknesses on soil hydrothermal conditions, soil fertility indicators, soil enzyme activities, and peanut growth and yield in a three-year field experiment. Three PBAT thicknesses (0.006, 0.008, and 0.010 mm) were compared with 0.010 mm polyethylene (PE) mulch and a bare soil control (CK). The effects of PBAT mulch films with different thicknesses on peanut yield, agronomic traits, photosynthetic characteristics, soil fertility indicators, and soil enzyme activities were systematically evaluated. PBAT008 showed the most favorable overall balance among the tested treatments. Compared with PE, PBAT008 significantly increased pod yield by 6.87–13.69% and 100-pod weight by 10.36–18.94%, whereas PE tended to reduce pod yield by 5.55–5.95% relative to CK. PBAT008 also promoted biomass accumulation and increased photosynthetic pigment content. Although PE showed the strongest water-retention capacity, PBAT008 maintained moderate soil moisture and suitable soil temperatures during pod formation. PBAT treatments improved soil organic matter, dissolved organic carbon, available phosphorus, and soil enzyme activities more effectively than PE. Path analysis identified available phosphorus, stem weight, and soil temperature as the strongest positive drivers of pod yield. Overall, PBAT008 enhanced peanut yield by achieving a coordinated improvement in soil hydrothermal conditions, soil fertility, and crop physiological performance, suggesting that an appropriate PBAT mulch thickness may provide an agronomically viable biodegradable alternative to PE mulch in peanut production.

Agricultural nonpoint-source phosphorus (NPS-P) losses threaten receiving waters, but regional control is complicated by differences in source intensity, erosion sensitivity, and hydrologic connectivity. This study jointly applied an improved export coefficient model (IECM), the Revised Universal Soil Loss Equation (RUSLE), Global and Local Moran statistics, and Getis-Ord Gi* analysis to six contrasting basins. The outputs were cross-interpreted without a formal composite index. Average annual soil erosion ranged from 1.96 to 18.47 t ha⁻¹ yr⁻¹, with very slight and slight erosion dominating all basins. Annual NPS-P export ranged from 2169.55 to 12,028.32 t yr⁻¹ (1.26–2.74 kg ha⁻¹ yr⁻¹), and cultivated land contributed 48.60–69.32% of modeled export. Under 999 random permutations, Global Moran’s I ranged from 0.615 to 0.834 (pseudo p = 0.001), and Gi* hot spots occupied 26.18–33.59% of valid cells. The basin-level perturbation analysis indicated greater ranking robustness for clearly high- and low-load basins than for intermediate basins, while the cultivated-land sensitivity analysis quantified the influence of the dominant coefficient. The framework supports regional screening, monitoring prioritization, and subsequent field verification rather than calibrated event-scale prediction.