It is unclear whether the production of biochar is economically feasible. As a consequence, firms do not often invest in biochar production plants. However, biochar production and application might be desirable from a societal perspective as it might entail net environmental benefits. Hence, the aim of this work has been to assess and monetize the environmental impacts of biochar production systems so that the environmental aspects can be integrated with the economic and social ones later on to quantify the total return for society. Therefore, a life cycle analysis (LCA) has been performed for two potential biochar production systems in Belgium based on two different feedstocks: (i) willow and (ii) pig manure. First, the environmental impacts of the two biochar production systems are assessed from a life cycle perspective, assuming one ton of biochar as the functional unit. Therefore, LCA using SimaPro software has been performed both on the midpoint and endpoint level. Biochar production from willow achieves better results compared to biochar from pig manure for all environmental impact categories considered. In a second step, monetary valuation has been applied to the LCA results in order to weigh environmental benefits against environmental costs using the Ecotax, Ecovalue, and Stepwise approach. Consequently, sensitivity analysis investigates the impact of variation in NPK savings and byproducts of the biochar production process on monetized life cycle assessment results. As a result, it is suggested that biochar production from willow is preferred to biochar production from pig manure from an environmental point of view. In future research, those monetized environmental impacts will be integrated within existing techno-economic models that calculate the financial viability from an investor’s point of view, so that the total return for society can be quantified and the preferred biochar production system from a societal point of view can be identified.

Plant biostimulants have gained great interest from the agrochemical industry and farmers because of their ability to enhance nutrient use efficiency and increase abiotic stress tolerance in crop production. However, despite the considerable potential of biostimulants for the sustainable development of the agricultural sector, the environmental evaluation of the application of biostimulants is still missing. Hence, this is the first study that focuses on the environmental assessment of the biostimulant action of arbuscular mycorrhizal fungus Glomus intraradices and vegetal-derived protein hydrolysate on two greenhouse vegetable crops, spinach and zucchini squash, under different fertilization regimes. The life cycle assessment from a cradle to gate perspective, which covers all processes related to crop cultivation up to harvest, was carried out to calculate the carbon footprint of the production chain for these two crops. The results of the comparative analysis revealed that the CO₂ equivalent emissions of both crops were reduced due to the biostimulant applications. In particular, the effect of the mycorrhization on the reduction of carbon emissions compared to the un-mycorrhized control was higher in zucchini plants under organic fertilization (12%) than under mineral fertilization (7%). In addition, organic fertilization increased the total carbon footprint of zucchini (52%) compared with mineral fertilization. The results also showed that an increase of nitrogen fertilization from 15 to 45 kg N ha⁻¹ in spinach production enhanced the total CO₂ emissions per ton of harvested leaves in comparison with treatments that involved the foliar applications of protein hydrolysate together with a lower nitrogen input; this increase was 4% compared to the unfertilized treatment with application of biostimulant. This study can support decision-making in terms of agronomic technique choices in line with sustainable development of vegetable crop production.