Organic agriculture has attracted attention as a method that uses environmentally conscious technologies and materials, and more businesses are starting to adopt it. At the same time, when viewed from multiple angles, there are potential risks and disadvantages depending on how it is implemented. This article focuses on organic fertilizers, one of the features of organic agriculture, and discusses the environmental and other impacts of organic agriculture from multiple perspectives. 

Importance of Sustainability in Agriculture 

Growing Interest in Sustainable Agriculture 

Interest in building a sustainable society is rising globally. According to Japan’s Third Basic Environment Plan approved by Cabinet decision in 2006, a sustainable society is defined as one in which “a sound and bountiful environment is conserved from the global scale down to local communities, and, through this, each and every citizen can enjoy a life in which they can genuinely feel happiness and which can be passed on to future generations.” (*1) 

The Ministry of the Environment states that, in order to achieve such a society, it is essential to ensure that the amount of pollutants emitted by human activities does not exceed the processing capacity of natural systems such as air, water, soil, and living organisms (*2). 

However, on a global scale, CO₂ emissions from human activity already exceed the absorption capacity of forests and other biological systems. While terrestrial ecosystems absorb an estimated 3.1 billion tons of CO₂ annually, global CO₂ emissions totaled about 31.4 billion tons in 2020, leaving 28.3 billion tons beyond natural processing capacity (*3)(*4). 

Greenhouse gases (GHG), including CO₂ and methane, have the function of trapping heat released from the sun within the Earth’s atmosphere and thereby raising temperatures at the Earth’s surface. Therefore, reducing GHG emissions is an urgent priority given natural processing limits (*5). 

In May 2020, the European Commission announced the European Green Deal, aiming to achieve net-zero greenhouse gas emissions by 2050. 

At the heart of this policy is the Farm-to-Fork Strategy (“F2F Strategy”), which is a far-reaching framework that covers all primary industries and encompasses the entire food system from production to consumption. It aims to build a fair, healthy, and environmentally conscious food system, while explicitly positioning the “ensuring of sustainable food production” as a core policy priority. As a result, the pursuit of sustainability is now required within the agricultural sector as well (*6)(*7). 

Concerns around Conventional Agriculture 

Conventional agriculture uses pesticides to control pests and weeds, and chemical fertilizers to promote growth and yields. These cultivation techniques have enabled efficient crop production, contributed to maintaining farmers’ livelihoods, and supported the supply of affordable agricultural products that are accessible to consumers (*8). 

However, conventional agriculture also imposes relatively high environmental burdens, and it has become clear that it is a farming system whose continued use is a cause for concern. 

For example, many of the chemical substances contained in the chemical fertilizers and pesticides that are characteristic of conventional agriculture impose various environmental burdens on the natural environment. Soils on which fertilizers and pesticides have been used become contaminated by toxic chemical substances and depleted in nutrients. As nutrients decline, more land becomes unusable, and chemical fertilizer application increases for recovery (*9). 

Manufacturing chemical fertilizers requires large amounts of energy (per kg of fertilizer: nitrogen fertilizer approximately 17,600 kcal; phosphate fertilizer approximately 3,200 kcal; potash fertilizer approximately 2,200 kcal) (*10). Burning fossil fuels emits CO₂, contributing indirectly to global warming (*11). 

Thus, conventional agriculture not only entails significant economic costs but also continues to impose long-term environmental burdens. 

Advantages of Environmentally Friendly Agriculture 

Since 1992, environmentally friendly agriculture has been promoted in Japan (*12). According to the Ministry of Agriculture, Forestry, and Fisheries, environmentally friendly agriculture is defined as “sustainable agriculture that makes use of the material cycling functions inherent in agriculture, gives due consideration to harmonization with productivity, and, through practices such as soil improvement, takes into account the reduction of environmental burdens caused by the use of chemical fertilizers and pesticides.” (*13) 

Specific examples include: 

• Cover cropping (green manure): a farming method in which green manure crops are grown and then incorporated into the soil when the land is tilled so that they serve as natural fertilizer and thereby reduce the use of chemical fertilizers. 

• Application of compost (“application of compost with high carbon sequestration effects that contributes to water quality conservation”): an initiative in which compost is applied before and after the growing period of the main crop. Compost refers to fertilizer produced by piling up and fully decomposing, through the action of microorganisms, plant materials such as dead grass, fallen leaves, and algae, as well as livestock manure such as poultry manure and cattle manure. However, in this initiative, composts whose main raw material is poultry manure are excluded (*14). 

• Organic agriculture: agriculture that avoids chemically synthesized fertilizers and pesticides, does not use genetic modification technology, and minimizes, as far as possible, the environmental impact arising from agricultural production (*15). 

Among these, organic agriculture, which aims to maintain the long-term sustainability of soils and to minimize the use of non-renewable resources, has attracted attention as an approach to comprehensive environmental conservation. Against this backdrop, this article focuses on organic agriculture and examines the functions it performs and the concerns it raises in the context of environmental conservation. 

 Evaluation of Organic Agriculture from a GHG Perspective 

Among the environmental indices used to quantitatively evaluate environmental quality, one that is familiar to many people is the greenhouse gas (GHG), mentioned at the beginning of this article. As noted earlier, because GHGs are the causative substances of global warming, reducing their emissions is an urgent issue (*5). 

According to Nature Communications, organic agriculture can reduce GHG emissions by up to 20% for crop products and up to 4% for animal products compared with conventional agriculture (*17)(*18). By fully shifting to organic agriculture and refraining from the use of nitrogen fertilizers, it is possible to reduce the amount of GHG directly emitted from agriculture (*18). 

However, research papers have also been published showing that, because organic agriculture simultaneously causes a decrease in production volume and therefore requires a larger production area, total greenhouse gas emissions can increase as a result. 

In organic agriculture, production volume can in some cases decrease by up to 40% compared with conventional agriculture. This is because, in conventional agriculture, the heavy use of pesticides and agricultural machinery makes it possible to achieve high crop yields. By contrast, organic agriculture is characterized by lower input use, and accordingly lower crop yields, which means that more production area is required to make up for the shortfall in production (*19). 

For this reason, while the environmental burden per unit of land in organic agriculture is considered to be lower than in conventional agriculture, the environmental burden per unit of product is thought to be higher in organic agriculture (*20). 

In this way, the reality is that simply being “organic agriculture” does not necessarily mean that it contributes to GHG reduction. 

Environmental Burden of Organic Fertilizer Use (Including Biodiversity) 

Organic agriculture is characterized by the use of organic fertilizers and pesticides composed of naturally derived ingredients. In this section, however, we focus specifically on the use of organic fertilizers and summarize the various environmental impacts associated with this characteristic. 

Potential Benefits 

The main potential benefits of organic fertilizer are as follows. 

1. Soil Improvement 

Organic fertilizers feed soil microbes, increasing microbial activity and promoting soil conditions favourable to crops. By suppressing nutrient losses such as nitrogen leaching and phosphorus fixation and thereby improving the nutrient utilization efficiency of crops, organic fertilizers help increase soil fertility (*21). 

In addition, part of the organic matter that is not decomposed by microorganisms remains in the soil and plays a role in promoting the formation of soil aggregates. As a result, organic matter improves properties such as aeration and water retention in the soil (*22). 

In this way, it has become clear that organic fertilizers have a far greater soil-improvement effect than chemical fertilizers. 

2.  Lower Risks to Human Health 

Replacing chemical fertilizers with organic fertilizers such as livestock manure reduces cadmium (Cd) input, lowering Cd concentration in soil and edible leafy vegetables (*23). Cadmium and its compounds are classified as carcinogenic substances by the International Agency for Research on Cancer (IARC). Cadmium is toxic and persistent; once ingested, it can remain in the human body for about 30 years (*24). For this reason, when cadmium is concentrated through the food chain, there is a risk that humans and other living organisms will be exposed to its toxicity over a long period of time. 

From the standpoint that such hazardous substances can be reduced, organic fertilizers can be regarded as safer than chemical fertilizers. 

3. Biodiversity 

The third benefit is its contribution to biodiversity. Organic agriculture that uses organic fertilizers is said to be superior to conventional agriculture from the perspective of biodiversity. 

Rich biodiversity is essential to maintain natural processes related to human life, such as pest control, pollination of fruit by insects, and the humification and decomposition of organic matter. Therefore, the loss of biodiversity not only has serious impacts on the environment but also becomes a significant burden on society as a whole. 

Specifically, two main risks can be identified. 

The first is the acceleration of global warming. Forests are ecosystems that absorb carbon dioxide. In other words, when biodiversity in forests declines, the natural systems that absorb carbon dioxide cease to function properly, and global warming accelerates. 

According to a paper published in 2021 by an international research group, if the loss of tree diversity could be prevented, 9–39% of the future predicted loss of forests’ carbon absorption function could be avoided. In other words, if tree diversity can be secured, the carbon absorption function of forests can be maintained, and it becomes possible to help curb global warming (*25). 

These research results show that biodiversity and global warming are closely linked, and they highlight how important the functions provided by biodiversity are. 

The second risk relates to human health. For example, freshwater, which is indispensable for humans, is supplied through the filtration and purification functions of wetlands. In addition, the ingredients of medicines that support human health involve some 50,000 to 70,000 plant species. Furthermore, high-quality soil inhabited by diverse microorganisms is essential for producing highly nutritious crops (*26). The loss of biodiversity, which currently supports human life in many ways, therefore has negative impacts on human health as well. 

Conventional, industrial, and highly intensive agriculture has caused the decline of farmland birds and a reduction in biodiversity, as confirmed in Slovenia since 2008. The World Trade Organization (WTO) has pointed out that 75% of crop varieties worldwide, and 90% of crop varieties in the EU, have disappeared over the past 100 years. 

By contrast, according to the Research Institute of Organic Agriculture (FiBL), the number of species and individuals living on farms practicing organic agriculture is 30% and 50% higher, respectively, than on farms practicing conventional agriculture (*27). 

In 2011, the European Parliament also adopted the “EU Biodiversity Strategy to 2020,” which aims to prevent biodiversity loss and ecosystem degradation. The conservation of biodiversity is becoming one of the major global issues today. From the perspective of contributing to biodiversity conservation, organic farming can be regarded as a method that should be practiced in place of conventional agriculture. 

The three points described above—soil improvement, reduction of human health risks associated with cadmium, and conservation of biodiversity—represent major advantages of organic agriculture. Taking these into account, organic fertilizers may appear to be an option that should proactively replace chemical fertilizers. Nevertheless, there are also several concerns associated with the use of organic fertilizers. 

Potential Risks

Despite these benefits, organic fertilizer also entails risks. 

1. Human Health Risks 

The first is health risks to the human body. As mentioned above, organic fertilizers help reduce cadmium concentrations, which are carcinogenic, but in some cases they can at the same time be accompanied by other human health risks that should be considered. 

1.1 Antibiotics 

In recent years, an initiative that has attracted attention is the recycling of food and livestock waste by converting such waste into organic compost and using it as organic fertilizer. These materials may contain antibiotics used in animal feed. 

Antibiotics are pharmaceuticals that serve to stop or suppress infections caused by bacteria such as bacilli. Strictly speaking, they are drugs that kill bacteria or inhibit their growth and thereby stop the spread of infection in the body, and in principle all drugs that have such effects are classified as antibiotics (*28). 

At first glance, the use of antibiotics seems reasonable in that it makes it possible to prevent diseases in livestock. However, administering antibiotics for the purpose of disease prevention means giving large amounts of antibiotics to animals that are not actually ill, which can lead to the emergence of bacteria (resistant bacteria) that have acquired resistance to those antibiotics. If such resistant bacteria infect humans, there is a possibility that infectious diseases will arise whose treatment and containment are difficult (*29). 

One example of an antibiotic for which resistant bacteria have actually emerged is colistin. Colistin has been highly valued by the medical community as one of the drugs used to treat multidrug-resistant bacteria that are resistant to multiple antimicrobial agents, and it has been used to treat infectious diseases in humans. 

However, in 2015 it was found that colistin-resistant bacteria had spread worldwide, and it became clear that the cause of the emergence of these resistant bacteria was the massive use of colistin in China and Europe to promote the growth of pigs (*30). 

According to Japan’s Ministry of Health, Labour and Welfare, more than 700,000 people worldwide were already dying each year due to resistant bacteria as of 2013. It has also been estimated that, if this situation is left unaddressed, the annual number of deaths could reach 10 million by 2050 (*31). 

Considering this aspect of antibiotics, which can cause harm not only to livestock but also to humans, it is necessary to use organic fertilizers with attention to the potential risks associated with antibiotics. 

1.2. Pathogens Causing Food Poisoning 

Animal-based fertilizers may contain pathogenic bacteria such as salmonella and E. coli O157. Proper fermentation over several months can kill these pathogens, but if fermentation is insufficient, there is a risk that pathogenic bacteria will remain in the fertilizer (*32). In the case of animal-based fertilizers, it is therefore essential to pay attention to the risk of food poisoning and to ensure appropriate treatment during production and use. 

2. Lower Productivity 

Across 25 crops, organic yields average 80% of conventional yields (*33). A 20% reduction in yield means that, to secure the same yield as conventional agriculture, 1.25 times as much farmland is required (*34). With limited farmland, expansion risks ecosystem destruction. 

Since farmland worldwide is limited and opening up new farmland leads to environmental destruction, it is necessary, when implementing organic agriculture, to devise ways to compensate for the weakness of lower yields. 

3. Limited Availability 

According to the Ministry of Agriculture, Forestry, and Fisheries, 42 official standards have been established for organic fertilizers, and there are many types of organic fertilizers. However, domestic production volumes are currently limited (*35). 

Rapeseed meal, the most widely used organic fertilizer, was not used as feed in the past because it contained components harmful to animal reproduction and was therefore used as fertilizer instead. In recent years, however, rapeseed varieties with reduced harmful components have been bred, and rapeseed is gradually being used as feed. As a result, the supply of rapeseed for use as fertilizer is declining. 

Furthermore, almost all rapeseed used as a raw material is imported, and large volumes of bone meal and other materials are also imported, indicating that organic fertilizers are highly dependent on imports. 

In this way, organic fertilizers are not only subject to supply constraints but are also becoming expensive due to competition with other uses (*36). 

As seen above, reviewing organic fertilizers from multiple perspectives shows that they can be evaluated as a better option than chemical fertilizers in terms of biodiversity and human health. At the same time, their risk profile varies depending on how they are used. Although organic fertilizers made from biological materials are often perceived more positively than chemical fertilizers, there are, as noted, several concerns associated with their use. Therefore, in the context of pursuing sustainable agriculture, it is necessary not only to apply organic agricultural practices but also to explore approaches that can compensate for the disadvantages inherent in this farming method. 

 
Therefore, even in the context of pursuing sustainable agriculture, it appears necessary not merely to implement organic agriculture, but to seek forms of agriculture that can complement the disadvantages of this farming method. 

New Approaches toward Sustainable Agriculture 

In light of the complexities surrounding organic agriculture described above, new approaches are emerging that go beyond simply practicing organic agriculture. Below we introduce two such initiatives. 

Combined Use of Organic and Chemical Fertilizers 

Chemical fertilizers, whose reduced use is being promoted, have the advantage that nutrients are delivered to plants immediately and effects appear in a short period of time; in other words, they act quickly. 

Therefore, rather than making a binary choice between organic and chemical fertilizers, it is possible to use fertilizers more efficiently by differentiating their roles based on their respective characteristics—for example, using organic fertilizer as a base fertilizer mixed into the soil before planting, and using chemical fertilizer as a top dressing during the growth phase (*37). 

 Introduction of New Technology: Mineralization of Organic Resources 

In 2012, a new technology was developed to produce inorganic fertilizers from organic resources such as food residues and livestock waste. The greatest advantage of this technology is that, by relying on the power of microorganisms to rapidly decompose organic matter and produce inorganic fertilizer, it does not require energy at the fertilizer manufacturing stage. 

As noted earlier, conventional chemical fertilizers normally require large amounts of energy at the manufacturing stage, which in turn necessitates the combustion of large quantities of fossil fuels. By contrast, this technology does not require energy at the fertilizer manufacturing stage and therefore can significantly reduce CO₂ emissions. 

In addition, organic resources such as livestock waste require large storage space. By converting these resources into inorganic fertilizers that are often considered superior in terms of fast-acting effectiveness. This also makes it possible to reduce storage costs and to export fertilizers in a form that is easier to handle (*38).  

In this way, in today’s agriculture, beyond the option of organic agriculture, there are also efforts to explore better forms of agriculture through combinations that leverage the strengths of both existing practices and emerging technologies, as well as through the development of new technologies. The progress of these various technologies suggests further diversification of agricultural systems in the future. 

As we have seen, organic agriculture is not only a topic of debate from the perspective of GHG, but also continues to reveal additional issues and new potential from various other perspectives. When examining the environmental impacts of agriculture, it is not sufficient to evaluate only one indicator such as GHG or to focus on only part of the production process. Regardless of the type of agriculture, it is necessary to conduct a comprehensive assessment that includes multiple environmental indices and impact categories. 

Usefulness of LCA in Evaluating Organic Agriculture 

In this context, what is considered useful for examining the environmental impacts of a product or service is an environmental impact assessment method called Life Cycle Assessment (LCA). LCA is a method for quantitatively evaluating the environmental burden over the entire life cycle of a product, from raw material procurement, manufacturing, processing, distribution, and sales through to disposal. 

In LCA, each step in the life cycle of a product is modelled, allowing the resources used for production and the weights of wastes and emissions generated in the process to be estimated. Based on LCA-specific impact category indicators, it is then possible to calculate the environmental burden. (For more details on LCA, please refer to our previous articles.) 

International sustainability assessments increasingly evaluate impacts across the entire life cycle. Quantifying and presenting a product’s environmental impacts from multiple perspectives in the form of indicators aligns with the broad interests of various stakeholders, including shareholders, business partners, and consumers, and contributes to more effective branding. 

However, LCA typically requires analyses that combine multiple databases for each product or service. In addition, implementing LCA involves practical challenges such as high costs, significant time requirements, and complex data extraction. 

Our system “My-Eco-Ruler” is particularly focused on organizing available data and standardizing analysis patterns in the fields of food and agriculture. It enables LCA to be carried out with high efficiency and supports product-level analysis and evaluation of various sustainability indicators, such as GHG and biodiversity-related indicators. It also has functions for converting these data and analysis results into indicators and communicating them externally, thereby supporting effective use of sustainability-related data to engage a wide range of stakeholders, including shareholders, business partners, and consumers. 

By having their own products evaluated scientifically and quantitatively, companies can objectively understand where their products stand in the environmental context within the overall food and agriculture market and can communicate more effectively to the market. 

We welcome inquiries regarding “My-Eco-Ruler.” 

”cuoncrop” ESG Global Trend Research Division 

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