The accumulation of allelochemicals in farming land has attracted a great deal of research attention, and biochar has shown positive effects in alleviating allelopathy. This study investigated how oligotrophic biochar application modulated salicylic acid (SA) generation in soybean roots through nutrient and oxidative stress pathways. Biochars were applied to soybean cultivation, with analyses conducted on nutrient adsorption, allelochemical profiles, and plant growth parameters. Results revealed that biochar suppressed benzoic acid (BA) while elevating SA levels, which correlated with the presence of persistent free radicals (PFRs) and nutrient retention. The retention of phosphorus (P) and ammonium (NH4+-N) dominated plant height reduction, surpassing oxidative stress effects linked to PFRs. Multivariate linear regression (MLR) identified P retention as the primary driver of SA generation, linked to adaptive phosphorus solubilization via acid secretion. Conversely, malondialdehyde (MDA) accumulation resulted from lipoxygenasemediated lipid peroxidation under nutrient stress and PFRs-induced oxidative stress. The strong adsorption of P and nitrate (NO3--N) by biochar exacerbated soil oligotrophy, triggering SA overproduction as a stress compensation mechanism. The significant correlation between SA and MDA indicated bidirectional stress signaling, wherein allelochemicals exacerbate oxidative damage while activating defense responses. These findings emphasize the dual role of biochar as both a stress inducer and an allelopathy modulator, highlighting the necessity for optimizing pyrolysis and developing soil-specific strategies to balance agricultural benefits with ecological risks.

Bioherbicides might be used to manage weeds as opposed to synthetic chemical herbicides, reducing environmental risks and advancing sustainable agriculture in the meantime. Bioherbicides employ different mechanisms of action to control weeds. Microbial bioherbicides may infect and damage weed plants, disrupt their growth, or produce compounds inhibiting weed development. Plant-derived bioherbicides often target specific biochemical processes crucial for weed survival. It can be applied through conventional spraying equipment, seed treatments, or soil incorporation. Bioherbicide development faces several challenges. One major hurdle is the complex diversity of weed species across different regions, requiring tailored bioherbicide solutions. The regulatory approvals for bioherbicides can be lengthy and costly, hindering widespread adoption. Scaling up production processes and ensuring product stability also pose challenges. By reducing reliance on chemical herbicides, bioherbicides can mitigate environmental pollution, protect non-target organisms, and promote sustainable agricultural practices. The development of locally adapted bioherbicides and strategic collaborations between researchers, industries, and policymakers could further enhance their prospects in a particular country. In addition, the knowledge gaps need to be addressed prior to adopting bioherbicides in agriculture. These review intended to explore the existing state of knowledge about the categories of bioherbicides, their formulation procedure, application approaches and mode of action to control weed. The bioherbicides that are currently on the market, their effects on weed physiology, and possible factors affecting their efficacy are all included in this review. Moreover, this review offers a perspective on existing challenges and future opportunities for adopting the bioherbicides in sustainable and eco-friendly agriculture.

Crops are often affected by NaCl, giant ragweed (Ambrosia trifida L.) and freeze-thaw stress simultaneously during their growth, and many areas in Northeast China are facing such serious ecological stress problems. In this experiment, the physiological responses of rye seedlings to NaCl and A. trifida extract stressor (AES) in a freeze-thaw environment were studied by artificial simulation technique. Malondialdehyde net photosynthetic rate (Pn) and transpiration rate (Tr) were determined and analyzed. The results showed that: After stress treatment, MDA and SP contents of rye seedlings increased by 19.48%-88.96% and 22.54%107.30%, SOD and CAT activities increased by 4.42%-26.60% and 23.31%-64.68% and Pn and Tr decreased by 40.00%-71.67% and 20.00%-80.00%. In the face of stress, rye seedlings can reduce the damage caused by stress by increasing osmotic substance and antioxidant enzyme activity, so as to adapt to the environment. The results revealed that combined NaCl, AES and freeze-thaw stress had a significant superposing effect on plants compared with single NaCl, AES and freeze-thaw stress. Net photosynthetic rate (Pn) and transpiration rate (Tr)as photosynthetic indices, are easily affected by the environment, and the photosynthetic physiological characteristics of plants will decrease significantly under external stress.