Vitamin C (VC), due to its chemical properties, can provide more oxygen-containing functional groups such as hydroxyl groups for biochar (BC), which promotes the adsorption of tetracycline on biochar. Therefore, in this study, cow dung biochar (CDBC) was modified with VC and VC-modified CDBC (CDBC-VC) was synthesized. The modified biochar was characterized and related factors, adsorption kinetics, isotherms and adsorption mechanisms were investigated. Adsorption kinetics indicate a fast rate of adsorption. The adsorption isotherms showed that the maximum adsorption capacity was 31.72 mg/g (CDBC) and 50.90 mg/g (CDBC-VC), respectively, and the adsorption process was inhomogeneous with multiple molecular layers and the adsorbent has a higher affinity. Mechanistic studies showed that hydrogen bonding interactions, π-π electron donor-acceptor interactions, hydrophobic interactions, and electrostatic interactions were the key to the adsorption process. The analysis of adsorbent regeneration showed that CDBC-VC had good adsorption performance. CDBC and CDBC-VC showed the best performance in simulated industrial wastewater with removal rates of 78.81% and 93.69%. The adsorption mechanism was comprehensively analyzed using six machine learning models. The extreme gradient boosting model gave the best fit. Analysis of the weights of the input variables for predicting adsorption efficiency showed that the ratio of initial TC concentration to BC dosage (29.8%), specific surface area (23%), isoelectric point (8.8%), and ash content (7.7%) had a significant effect on the predicted results.

Cadmium (Cd) contamination in maize poses a significant threat to global food security due to its persistent accumulation in crops. In this study, the effects of foliar application of glycerol on Cd accumulation in maize seedlings were studied. Our results demonstrated that under Cd treatment, biomass, total chlorophyll content, net photosynthetic rate (Pn), Ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBisCO) activity, Phosphoenolpyruvate carboxylase (PEPC) activity, sucrose levels, and carbohydrate levels in maize seedlings significantly increased after glycerol application. H₂O₂ and MDA levels in both the aboveground and belowground portions of the maize plants significantly decreased. Moreover, superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT) activities in the aboveground parts significantly increased. Notably, maize plants used glycerol to chelate Cd, which was fixed within the cell wall and soluble fraction of the roots, reducing Cd transport to the shoots and significantly lowering the Cd transport coefficient (TF). Transcriptomic data suggested that glycerol-mediated alleviation of Cd stress in maize seedlings may be associated with phenylpropanoid biosynthesis, plant-pathogen interactions and photosynthesis pathways. These molecular patterns align with the observed physiological improvements. This study provided a novel approach to effectively alleviate excessive Cd in maize and suggested possible applications of glycerol in cultivating plant resistance to heavy metals.

In Northeast China, waterlogging has emerged as a significant challenge due to climate change, particularly during the June–August period when spring maize (Zea mays L.), at the post-tasseling phase, impedes a comprehensive understanding of responses and the development of resistance technologies. 2-(3,4-dichlorophenoxy) triethylamine (DCPTA) is suitable for the entire lifecycle of various economic and food crops, improving crop quality and enhancing stress resistance. The study investigated the ear leaf photosynthesis in relation to the root antioxidant systems’ differential responses of spring maize to waterlogging among the tasseling (VT), vesicle (R2) and dough (R4) stages, and the exogenous DCPTA regulating effect. Results revealed that waterlogging inhibited root physiological activity due to oxidative damage. Consequently, the stomatal restriction and non-stomatal restriction on photosynthesis appeared successively, and R4 was the most sensitive stage. Pretreatment with DCPTA reduced stomatal restriction by maintaining water transfer to the leaf through maintaining root physiological activity via enhanced ascorbate–glutathione cycle. Delayed non-stomatal restriction appeared due to relatively stable chlorophyll content and photosynthetic activities, and VT stage exhibited the highest susceptibility to DCPTA. The study provides a necessary theoretical foundation for comprehending the physiological mechanisms underlying yield formation of spring maize under waterlogging stress in Northeast China, and offers valuable insights for the development of chemical regulation technology.

Straw and cattle manure are common agricultural wastes, and their composting plays a critical role in regional nutrient cycling and organic carbon management. During composting, the structural evolution and humification processes of dissolved organic matter (DOM), fulvic acid (FA), and humic acid (HA) are regulated by environmental factors such as temperature and pH. However, systematic studies on the multi-component fluorescence characteristics of DOM in straw–manure systems and their coupling with environmental variables remain limited. In this study, maize straw and cattle manure were used as raw materials, with four mixing ratios (T1–T4: 2:8, 4:6, 6:4, and 8:2), to investigate the effects of raw material proportions on the structural evolution of DOM, fulvic acid (FA), and humic acid (HA) during composting. Three-dimensional fluorescence spectroscopy combined with parallel factor analysis (EEMs-PARAFAC) was applied to characterize organic components, their transformation patterns, and their relationships with environmental factors. The EEMs-PARAFAC identified 3, 2, and 3 components for DOM, FA, and HA, respectively. Moderate straw–cow manure ratios (T2 and T3) maintained high microbial activity while promoting humic-like component accumulation and FA-to-HA conversion. Fluorescence indices indicated mixed substrate-derived and microbial sources for DOM, predominantly microbial origins for FA, and a shift in HA from substrate-derived to mixed sources. Overall, humification remained low (humification coefficient < 1.5), reflecting an early composting stage. Mantel analysis and partial least squares path modelling (PLS-PM) revealed temperature as the dominant factor associated with HA formation, whereas an alkaline pH inhibited humification. These findings clarify how substrate ratios regulate humification via environmental microhabitats, providing a theoretical basis for optimizing straw–manure co-composting and enhancing compost stability and soil carbon sequestration.

Potato (Solanum tuberosum L.) is a chlorine-sensitive crop. When soil Cl⁻ concentrations exceed optimal thresholds, the yield and quality of potatoes are limited. Consequently, chloride-containing fertilizers are rarely used in actual agricultural production. Therefore, two years of field experiments under natural rainfall regimes with three chlorine application levels (37.5 kg ha⁻¹/20 mg kg⁻¹, 75 kg ha⁻¹/40 mg kg⁻¹, and 112.5 kg ha⁻¹/60 mg kg⁻¹) were conducted to investigate the leaching characteristics of Cl⁻ in field soils with two typical textures for Northeast China (loam and sandy loam soils). In this study, the reliability of Cl⁻ residual estimation models across different soil types was evaluated, providing critical references for safe chlorine-containing fertilizer application in rain-fed potato production systems in Northeast China. The results indicated that the leaching efficiency of Cl⁻ was significantly positively correlated with both the rainfall amount and the chlorine application rate (p < 0.01). The Cl⁻ migration rate in sandy loam soil was significantly greater than that in loam soil. However, the influence of soil texture on the Cl⁻ leaching efficiency was only observed at lower rainfall levels. When the rainfall level exceeded 270 mm, the Cl⁻ content in all the soil layers became independent of the rainfall amount, soil texture, and chlorine application rate. Under rain-fed conditions, KCl application at 80–250 kg ha⁻¹ did not induce Cl⁻ accumulation in the primary potato root zone (15–30 cm), suggesting a low risk of toxicity. In loam soil, the safe application range for KCl was determined to be 115–164 kg ha⁻¹, while in sandy loam soil, the safe KCl application range was 214–237 kg ha⁻¹. Furthermore, a predictive model for estimating Cl⁻ residuals in loam and sandy loam soils was validated on the basis of rainfall amount, soil clay content, and chlorine application rate. The model validation results demonstrated an exceptional goodness-of-fit between the predicted and measured values, with R² > 0.9 and NRMSE < 0.1, providing science-based recommendations for Cl-containing fertilizer application to chlorine-sensitive crops, supporting both agronomic performance and environmental sustainability in rain-fed systems.