Intensive conventional agriculture and climate change have induced severe ecological damages and threatened global food security, claiming a reorientation of agricultural management and public policies towards a more sustainable development model. In this context, nanomaterials promise to support this transition by promoting mitigation, enhancing productivity, and reducing contamination. This review gathers recent research innovations on smart nanoformulations and delivery systems improving crop protection and plant nutrition, nanoremediation strategies for contaminated soils, nanosensors for plant health and food quality and safety monitoring, and nanomaterials as smart food-packaging. It also highlights the impact of engineered nanomaterials on soil microbial communities, and potential environmental risks, along with future research directions. Although large-scale production and in-field testing of nano-agrochemicals are still ongoing, the collected information indicates improvements in uptake, use efficiency, targeted delivery of the active ingredients, and reduction of leaching and pollution. Nanoremediation seems to have a low negative impact on microbial communities while promoting biodiversity. Nanosensors enable high-resolution crop monitoring and sustainable management of the resources, while nano-packaging confers catalytic, antimicrobial, and barrier properties, preserving food safety and preventing food waste. Though, the application of nanomaterials to the agri-food sector requires a specific risk assessment supporting proper regulations and public acceptance.

Cadmium, Cd(II) pollution of soils is a serious environmental and agricultural issue, posing a threat to crop production, environmental quality, food safety, and human health. Therefore, immobilization of Cd(II) in soils is crucial. Biochar-based materials are receiving significant attention as Cd(II) immobilizers, due to their multifunctional surface properties. The remediation/immobilization mechanisms involved are, mainly, surface complexation, chemical reduction, precipitation, ion exchange, π–π interactions, hydrogen bonding, and adsorption. These mechanisms are mostly dependent on biochar surface pore size, oxygen-containing functional groups, pyrolysis temperature used in biochar preparation, biochar feedstock, and soil characteristics. So far, various pristine and modified biochar substrates have been used to remediate heavy metal-contaminated soils. Therefore, in this review paper, we briefly summarize the chemical forms, release sources, and maximum permissible limits of Cd(II) in soil. We also summarize recent scientific findings on the performance of biochar substrates in Cd(II)-contaminated soils to minimize Cd(II) mobility, bioavailability, and potential accumulation in crops. Finally, we identify challenges associated with the use of biochar and suggest areas for future research. The review presents an overview of the knowledge of biochar as a promising amendment for the decontamination of Cd(II)-polluted soils.

To overcome the problems associated with soil phosphorus (P) insolubility, soil inoculation with phosphate-solubilizing bacteria (PSB) can be used. In a field experiment, we evaluated the efficacy of PSB in enhancing mungbean P acquisition, nitrogen (N) fixation, and morphological and yield traits in alkaline-calcareous soil when added together with P as single superphosphate (SSP) or rock phosphate (RP) at 45 or 90 kg P₂O₅ ha⁻¹. Coupling PSB with mineral P fertilizers (SSP & RP) improved P use efficiency, mungbean P acquisition, N₂ fixation, nodulation, NP uptake, and the morphological and yield-related traits of mungbeans compared with non-fertilized controls and plots received P from mineral sources alone. Soil PSB inoculation with mineral P also improved post-harvest soil fertility relative to pre-harvest by improving soil organic matter from 0.61% to 0.70%, lowering pH from 7.74 to 7.68, and improving soil total N from 0.04 to 0.09%, ABDTPA-extractable P from 2.07 to 3.44 mg kg⁻¹, and potassium (K) concentrations from 100.27 to 129.45 mg kg⁻¹. When combined with PSB, RP generally performed better than SSP. Moreover, there was a significant correlation between soil N and plant N, while the correlation between soil P and plant P was non-significant. The correlation between soil organic matter content and NP uptake by mungbeans was also non-significant. Therefore, adding P as RP at 45–90 kg ha⁻¹, together with PSB inoculation, can be recommended for improving mungbean P acquisition, use efficiency, optimum N₂ fixation, and yield in alkaline-calcareous soils.

Purpose: Humic substances (HSs) and biochar (BC) are carbon-based soil amendments. These amendments improve soil health and fertility, enhance nutrient pools and carbon content, remove soil pollutants, and enhance plant performance. As a result, they contribute to agro-environmental sustainability and the development of a circular bioeconomy. However, there is a lack of research on the effects of HSs-aged BC or the co-application of BC and HSs on the agro-environmental system. Therefore, further studies are needed to understand the impacts of these amendments on the agro-environmental system. Methods: This study utilizes a novel technique based on BC aging with HSs to investigate the BC-aging process, factors influencing it, as well as the impact of BC and HSs on soil physicochemical properties, nutrient pools, microbial communities, immobilization of metal ions in the soil, and plant performance. We gathered original research articles, meta-analysis papers, book chapters, conference proceedings, and technical notes from high-quality peer-reviewed journals and reputable websites. Results and discussion: The extensive literature evaluation revealed that the potential benefits of BC are closely related to variations in the physicochemical composition of the BC and soil because microorganisms do not prefer fresh BC for colonization. In some studies, BC showed a detrimental impact on the soil microbiome. Therefore, the influence of BC on the soil microbiome, nutrient pool, pollutant removal, and plant growth strongly depends on the residence time of BC in the soil and its prior aging with HSs. Aging BC with HSs is more effective than using fresh BC as it enhances nutrient pools, accessibility to plants, pollutant amelioration capacity, microbial activities, and consequently, plant performance due to the presence of surface functional groups and the adsorbed nutrient-rich organic molecules. Conclusions: The soil fertility traits and plant performance were impacted by aging or a combination of BC with HSs. However, detailed characterizations and continuous experiments are required to gain in-depth insights into the interaction mechanisms between the aging of BC with HSs via the liquid soaking technique and soil fertility traits.