The use of biochar for soil improvement and emission reduction has been widely recognized for its excellent performance. However, the choice of feedstock and pyrolysis temperature for biochar production significantly affects its surface parameters and interactions with soil substances. In this study, we retrieved 465 peer-reviewed papers on the application of biochar in reducing greenhouse gas emissions and nutrient losses in soil and analyzed the changes in biochar physicochemical parameters from different feedstock and pyrolytic temperatures. Molecular simulation computing technology was also used to explore the impacts of these changes on the interaction between biochar and soil substances. The statistical results from the peer-reviewed papers indicated that biochar derived from wood-based feedstock exhibits superior physical characteristics, such as increased porosity and specific surface area. Conversely, biochar derived from straw-based feedstock was found to contain excellent element content, such as O, N, and H, and biochar derived from straw and produced at low pyrolysis temperatures contains a significant number of functional groups that enhance the charge transfer potential and adsorption stability by increasing surface charge density, charge distribution and bonding orbitals. However, it should be noted that this enhancement may also activate certain recalcitrant C compounds and promote biochar decomposition. Taken together, these results have significant implications for biochar practitioners when selecting suitable feedstock and pyrolysis temperatures based on agricultural needs and increasing their understanding of the interaction mechanism between biochar and soil substances.

Biochar has been extensively utilized to amend soil and mitigate greenhouse gas (GHG) emissions from croplands. However, the effectiveness of biochar application in reducing cropland GHG emissions remains uncertain due to variations in soil properties and environmental conditions across regions. In this study, the impact of biochar surface functional groups on soil GHG emissions was investigated using molecular model calculation. Machine learning (ML) technology was applied to predict the responses of soil GHG emissions and crop yields under different biochar feedstocks and application rates, aiming to determine the optimum biochar application strategies based on specific soil properties and environmental conditions on a global scale. The findings suggest that the functional groups play an essential role in determining biochar surface activity and the soil’s capacity for adsorbing GHGs. ML was an effective method in predicting the changes in soil GHG emissions and crop yield following biochar application. Moreover, poor-fertility soils exhibited greater changes in GHG emissions compared to fertile soil. Implementing an optimized global strategy for biochar application may result in a substantial reduction of 684.25 Tg year⁻¹ CO₂ equivalent (equivalent to 7.87% of global cropland GHG emissions) while simultaneously improving crop yields. This study improves our understanding of the interaction between biochar surface properties and soil GHG, confirming the potential of global biochar application strategies in mitigating cropland GHG emissions and addressing global climate degradation. Further research efforts are required to optimize such strategies. Graphical Abstract

Excessive nutrient loss from farmland located on the west bank of Erhai Lake has resulted in significant non-point source pollution within the Lake Erhai basin. However, mitigating this issue proves challenging due to the intricate nature of soil properties and environmental factors. Here, during the rainy season in the Lake Erhai basin, we collected and analyzed soil profile samples, 35 topsoil (0–20 cm) samples, and more than 300 field baseflow samples. Our objective was to explore the influences of soil properties, field baseflow, and agricultural management measures on the spatiotemporal migration of nutrients. The results indicated that the concentration of soil organic matter (SOM) has a significant impact on the spatial patterns of nutrient distribution in sandy soil. Consequently, this leads to a substantial reduction in the potential for nutrient loss in the Lake Erhai basin. The vegetable-field baseflow exhibited the highest concentrations of nitrogen and phosphorus when subjected to high fertilization and flood irrigation. The concentrations of TN and TP in baseflow increase by a factor of 2 and 7.7, respectively, during rainfall compared to periods of no rainfall. Optimizing agricultural measures, such as replacing chemical fertilizers with organic fertilizers and modifying irrigation methods to enhance the organic content of sandy soil and minimize baseflow elution, has a beneficial impact on mitigating agricultural non-point source pollution in the Erhai Lake basin. The research results can enable us to have a more systematic understanding of the problem of non-point source pollution in the Erhai River Basin, and provide a theoretical basis for developing targeted agricultural non-point source pollution mitigation plans. Simultaneously, optimizing agricultural management models to strike a balance between agricultural economic development and ecological protection issues holds significant practical significance for managers.

Soil acidification seriously threatens sustainable agriculture by promoting phytotoxic exchangeable aluminum ions (Al3+) accumulation and impairing crop growth. However, conventional soil amendments, such as lime and biochar, have known limitations, making the introduction of more sustainable soil amendments crucial for mitigating soil acidification. Furthermore, the biological and chemical mechanisms by which amendments alleviate acidification and enhance soil fertility remain unclear. This impedes the search for more cost-effective soil amendments to rehabilitate infertile acidic soils. In this study, pot experiments, microbial sequencing, and molecular modeling calculations were employed to assess the response of soil fertility and maize yield to the combined application of sodium carboxymethylcellulose (CMC) and desulfurized phosphogypsum (DP) in strongly acidic soils, as well as the underlying biological and molecular dynamic mechanisms. The results indicated that CMC + DP significantly reduced soil exchangeable Al3+ by 78.68–79.60%, while enhancing the base ion concentration by 59.93–102.27% and acid buffering capacity by 46.47–49.55% compared to the control (CK) in strongly acidic soils. Additionally, CMC + DP-amended soil exhibited a 24.47–48.65% increase in photosynthetic rate and a 50.57–155.48% increase in the weight of 100 grains. CMC contributed to Al3+ immobilization and base ion release via competitive electrostatic attraction and complexation of Al3+ on the surface of –COOH and –OH functional groups. CMC + DP application promoted direct enrichment of microbial communities, increasing the abundance of functional microbial taxa, including Acidobacteriota, Gemmatimonadota, and Ascomycota, and soil enzymes related to organic matter decomposition and phosphorus metabolism. These findings suggest that CMC + DP could be used as a promising strategy to mitigate soil acidification, enhance soil fertility and crop yield, and highlight the synergistic potential of biodegradable polymers and industrial by-products for acidic soil remediation. They enhance our understanding of the synergistic biological and molecular dynamic mechanisms of amendments, mitigating soil acidification and enhancing soil fertility. These findings may help identify more effective soil amendments and application strategies to ensure cropland health and promote sustainable agriculture.