Biofertilizers Fall Short on Social Sustainability, Landmark Spanish Assessment Finds

The circular bioeconomy has been celebrated as a transformative framework for sustainable development, promising to replace fossil-dependent industrial processes with renewable, waste-recycling value chains. Yet a new study published in the Journal of Industrial Ecology suggests that while these bio-based systems excel on environmental credentials, their social performance remains surprisingly shallow. In the first application of Social Organizational Life Cycle Assessment, or SO-LCA, to the biofertilizer sector, researcher Irene Zarauz of the University of Zaragoza evaluated twelve organizations participating in a Spanish biofertilizer production chain and found that most companies merely meet baseline social requirements, with proactive efforts toward genuine social transformation remaining scarce.

The stakes of this question are considerable. Roughly a quarter of the world’s soils are severely degraded and 44 percent are moderately degraded, while only about 10 percent are under recovery. Conventional fertilizers, indispensable for feeding a growing population, depend on natural gas for nitrogen production and on finite, geologically concentrated mineral reserves for phosphorus and potassium. This dependency has repeatedly translated into social harm: fertilizer costs accounted for up to 60 percent of food price increases during the 2007–2008 crisis, and supply dependencies triggered further price surges in 2022, intensifying global hunger and food insecurity. Biofertilizers, which recycle nitrogen, phosphorus and potassium from renewable biological sources, are widely promoted as a way to decouple food production from these volatile supply chains.

Despite this promise, the social dimension of the circular bioeconomy has been chronically underexplored. Social Life Cycle Assessment, a methodology for quantifying social impacts across product life cycles, has been applied to fertilizers only twice before, and never through its organizational counterpart. SO-LCA, formally defined in the United Nations Environment Programme’s 2020 guidelines and recently standardized as ISO 14075, shifts the unit of analysis from products to organizations, allowing researchers to use actual, verifiable performance data rather than generic risk databases. This makes it particularly powerful for strategic decision-making, such as supplier selection, and for aligning corporate behavior with evolving environmental, social and governance standards.

Zarauz conducted the study in collaboration with a major Spanish fertilizer producer employing approximately 70 people, located in a severely depopulated region of inland Spain. The company’s bio-value chain comprises two production lines: one manufacturing amino acid-based biofertilizers derived primarily from animal waste, and another producing plant-based biofertilizers with biologically available potassium. Together these lines deliver the three essential macronutrients—nitrogen, phosphorus and potassium—and are composed of more than 80 percent renewable and circular resources, with the notable exception of phosphorus, which is sourced from mineral inputs. The assessment adopted a cradle-to-gate perspective covering the company’s total annual activity for 2022.

Methodologically, the study followed the UNEP guidelines and the Subcategory Assessment Method, a characterization approach that benchmarks organizational behavior against Basic Requirements derived from international agreements, legislation and recognized practices. Performance is classified into four levels, from A, denoting excellent and proactive social behavior, to D, indicating poor performance. Data collection combined two years of participant observation within the corporate group with two stakeholder surveys. A first questionnaire, distributed to a sample of 100 stakeholders including employees, clients, suppliers, nonprofits, government bodies and academic experts, achieved a 70 percent response rate and identified 22 material social subcategories out of 35 proposed in the UNEP methodological sheets. A second questionnaire gathered empirical data from the reporting organization and eleven suppliers, all based in Spain except one located in Morocco, with responses substantiated by documentation such as audited sustainability reports, policies and certificates.

The results reveal a pattern of reactive rather than transformative social conduct. In the Workers category, full compliance was achieved in freedom of association, child labor, employment relationships, sexual harassment prevention and social benefits, with all organizations upholding the right to organize, refraining from employing anyone under 16, maintaining formal contracts and providing at least two social benefits such as parental leave, healthcare or vocational training. Yet no organization exceeded these baseline requirements in these subcategories. Quantitative indicators showed high variability: equal opportunities and non-discrimination scored lowest, with five organizations failing to meet the Basic Requirement and none achieving strong performance, reflecting the persistent underrepresentation of women in the sector.

Gender equity emerged as the most significant gap in the entire value chain. Female participation in the studied organizations aligns with the unequal, traditional structure of Spain’s primary sector, where women hold roughly 24 percent of jobs, rather than approaching the 46 percent observed in the chemical sector. The study argues that this imbalance is structural, rooted in the inertia of rural contexts, and constitutes the primary barrier to the social sustainability of the bio-value chain. Remuneration told a similar story of minimal compliance: while minimum wage adherence was universal, only three companies—characterized by a stronger focus on technological innovation—surpassed the living wage threshold.

Local community results offered a more encouraging but nuanced picture. Local employment performance was consistently strong among the seven entities assessed, underscoring the potential of the circular bioeconomy to mitigate regional socio-economic disparities in depopulated rural areas. Environmental and health certifications such as ISO 14001 and ISO 45001 were present in 75 and 83 percent of cases respectively, and nearly 70 percent of the chain demonstrated satisfactory community engagement through donations and partnerships. However, the study notes that many organizations show limited commitment to territorial improvement, suggesting that local job creation alone is insufficient without deeper social responsibility. Meanwhile, consumer health and safety, transparency and end-of-life responsibility were largely satisfactory, though two entities performed poorly on labeling and safety standards and two lacked any public sustainability reporting, typically smaller organizations.

The most striking finding concerns phosphorus. The single supplier located outside Spain, which provides this critical input, exhibited deficient performance in prevention and mitigation of armed conflicts and in safe living conditions. Its operations are linked to Western Sahara, a disputed territory under Moroccan control that holds 72 percent of global phosphate reserves, where extraction has triggered environmental justice conflicts marked by dispossession, loss of local identity and increased social vulnerability. Phosphorus is designated a critical raw material in Europe, and its concentration in geopolitically sensitive areas reproduces fossil-fuel-like dependency, neo-colonial tensions and structural asymmetries—precisely the dynamics the circular bioeconomy claims to transcend. The study found limited evidence of renewable phosphorus alternatives among the biofertilizer business models examined.

Zarauz concludes that the social contribution of biofertilizers to sustainable food systems is mediated by governance and organizational practices rather than guaranteed by their bio-based nature. While the circular bioeconomy can strengthen social capital in declining rural areas by fostering local autonomy and decoupling production from volatile global mineral chains, its tangible contributions to socially sustainable development remain limited without deliberate policy intervention. The study calls for targeted policies promoting prosocial organizational behavior, improved nutrient recycling, and the development of circular and renewable phosphorus alternatives to mitigate social risks across the bio-value chain. Future research, the author suggests, should extend SO-LCA applications in the biofertilizer sector beyond Spain and continue probing the social dimensions of the circular bioeconomy to support a genuinely sustainable transition—one in which environmental innovation and social justice advance together rather than in isolation.

Subject of Research: Social sustainability assessment of a biofertilizer value chain in the circular bioeconomy using Social Organizational Life Cycle Assessment

Article Title: Assessing social sustainability in the circular bioeconomy: a SO-LCA approach to a biofertilizer value chain

Article References: Zarauz, I. (2026). Assessing social sustainability in the circular bioeconomy: a SO-LCA approach to a biofertilizer value chain. Journal of Industrial Ecology. https://doi.org/10.1007/s44498-026-00156-3

Image Credits: AI Generated

DOI: 10.1007/s44498-026-00156-3

Keywords: circular bioeconomy, biofertilizers, social sustainability, SO-LCA, life cycle assessment, phosphorus, gender equity, rural development, agri-food systems, Spain, value chain, UNEP guidelines