Bio-based fertilizers as a sustainable alternative of synthetic fertilizers
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Bringing circularity in the fertilizer production system
There is an increasing interest and focus on circular economy that advocates for sustainable development and cultivation. In this context, fertilizer production industries are also being sustainably revolutionized through innovative approaches via recovering nutrients from organic waste sources. Also, there is a pressing need to transition towards a “circular” approach in managing our production systems, driven by the urgency in managing and combating climate change. Sustainable nutrient management is necessary.
The problem with our current fertilizer production system
The linear production system based on “take-make-consume-throw” approaches accounts for rising global issues such as waste generation, environmental pollution, threatening wildlife, and contributing to greenhouse gas emissions. In the case of “fertilizer production,” the current methods primarily rely on the exploitative mining of scarce resources like phosphorus (P) and involve energy-intensive processes, notably in the case of nitrogen (N) production. This approach to production has the potential to yield hazardous consequences for humanity due to the following reasons:
- We cannot create or substitute phosphorus within our food system. Phosphorus is a vital element for all life forms, having been designated as a “critical raw material” by the European Commission in 2014.
- Fossil fuel-derived energy continues to serve as the dominant source that sustains various big industries, including the production of nitrogen-based fertilizers.
Therefore, recovering nutrients from organic sources and using them as fertilizers would directly diminish waste (i.e., organic waste) and lessen the danger to wildlife and greenhouse emissions linked with waste sources. Also, bringing circularity in the fertilizer production system is the solution for the “Phosphate Fertilizer Crisis,” and it replaces the emission-intensive way of producing N fertilizers with an innovative emission-reduced production system (e.g., biogas produced from anaerobic digestion can be used as the primary energy source).
Figure 1. Converting waste into energy: Anaerobic digestion process (Illustration graphic by Sara Tanigawa, EESI). More on “Biogas” production: https://www.eesi.org/papers/view/fact-sheet-biogasconverting-waste-to-energy).
What are Bio-Based Fertilizers?
The central concept of producing “Bio-Based Fertilizers” lies in recovering plant-available nutrients from bio-based or organic-based substances (animal, plant, or microbial origin, residues, organic wastes, etc.) for their subsequent use as fertilizers in agriculture (Albert & Bloem, 2023). Currently, there are more than 100 various nutrient recovery technologies, as reported by the European Commission (2019), and different processing methods accordingly (Figure 2). Because this field is relatively new, innovative methods for extracting nutrients from diverse sources are still being explored. For example, a team of researchers discovered a method to produce a nitrogen-rich liquid fertilizer using chicken feathers, which are abundant and contain substantial nitrogen content (Nurdiawati et al., 2018).
It is important to acknowledge that there is currently no universally accepted standard term for labeling products derived from organic waste or bio-based materials. Nevertheless, “bio-based fertilizer” is the most frequently utilized and referenced term in the literature concerning this field.
Figure 2. Examples of bio-based or organic materials and processes to produce “Bio-Based Fertilizers” (Albert & Bloem, 2023).
Why are Bio-Based Fertilizers becoming popular in recent years?
What are the advantages of Bio-Based Fertilizers?
As we mentioned above, the production of synthetic fertilizers is associated with significant problems, including the carbon-intensive manufacturing process and the depletion of finite sources of raw materials. As the global population continues to grow, the stress on agricultural lands (for higher yields) will also increase. However, the availability of phosphorus (P) is limited, and there is a pressing need to reduce emissions to avoid/lessen the devastating consequences of climate change. Consequently, scientists are inclined to innovate, and policymakers are inclined to support the solutions that are aimed at mitigating and addressing climate change, where the production of bio-based fertilizers is among these solutions. For instance, there is a rising research interest in developing new technologies for recycling resources and recovering nutrients for farmers’ use in the USA (namely the US Environmental Protection Agency) and Europe (research project funding under the Green Deal call).
Since this area is relatively new, these innovative production systems are costly to adopt. Moreover, numerous challenges and knowledge gaps exist in this domain. These include concerns about transportation and production costs, regulations, the influence of bio-based fertilizers on soil microorganisms, environmental risks, inconsistent nutrient contents of end-products, matching crops, and policy frameworks.
References:
Albert, S., & Bloem, E. (2023). Ecotoxicological methods to evaluate the toxicity of bio-based fertilizer application to agricultural soils – A review. In Science of the Total Environment (Vol. 879). Elsevier B.V. https://doi.org/10.1016/j.scitotenv.2023.163076
European Commission. (2019, November 11). 100 nutrient recovery technologies and novel fertiliser products.
Nurdiawati, A., Nakhshiniev, B., Zaini, I. N., Saidov, N., Takahashi, F., & Yoshikawa, K. (2018). Characterization of potential liquid fertilizers obtained by hydrothermal treatment of chicken feathers. Environmental Progress and Sustainable Energy, 37(1), 375–382. https://doi.org/10.1002/ep.12688
