From Soil to Soil: Are We Disrupting the Nutrient Cycle?

We often take for granted that the fruits and vegetables we consume derive their nutrients from the soil. Ancient traditions remind us that all living things, including humans, come from the soil and return to it. However, with rapid urbanization and the inability of governments to manage growing waste, organic matter like vegetable peels, fruit waste, and even fish bones end up rotting in landfills. This disrupts the natural soil cycle, depriving the earth of essential nutrients.

When organic waste decomposes anaerobically in landfills, it produces methane, a potent greenhouse gas. This process prevents the waste from returning valuable nutrients to the soil, disrupting the nutrient cycle. By not composting organic waste, we miss the opportunity to enrich the soil and reduce our carbon footprint.

The Hidden Impact of Organic Waste

When organic waste decomposes anaerobically in landfills, it produces methane, a potent greenhouse gas. This process prevents the waste from returning valuable nutrients to the soil, disrupting the nitrogen cycle and contributing to nitrogen pollution. By not engaging in organic waste recycling through methods like composting, we miss the opportunity to enrich the soil and reduce our carbon footprint. Moreover, less than 2% of the nutrients in urban waste streams are currently recovered and recycled back into our food system, leading to a broader nutrient cycle disruption.

Understanding the Natural Nutrient Cycle

The nutrient cycle is nature's way of recycling organic matter, breaking it down into nutrients that are absorbed by the soil and used by plants to grow. This cycle is vital for maintaining soil fertility, supporting healthy plant growth, and ensuring that ecosystems thrive. However, the balance of this cycle is delicate and can easily be disrupted.

For instance, agriculture significantly contributes to this disruption by releasing around 5 million metric tons of nitrous-oxide annually—a greenhouse gas that accelerates global warming and contributes to nitrogen pollution. When the carbon and nitrogen cycles are disrupted, it impacts soil health and has far-reaching consequences for our environment.

Soil Health and the Role of Organic Matter

Organic matter is the lifeblood of soil health, promoting robust plant growth and maintaining the soil’s structure. When organic waste is composted, it returns essential nutrients to the soil, closing the nutrient loop and enhancing soil fertility. Unfortunately, when organic matter ends up in landfills, it not only contributes to methane emissions but also robs the soil of nutrients that are critical for life.

Composting is a sustainable method of processing organic waste, transforming it into nutrient-rich compost that can improve soil health. However, decentralized composting faces challenges, particularly when mixed waste collections reduce the quality of organic waste, making it harder to produce high-quality compost or biogas. Contaminated compost can also introduce harmful substances like heavy metals, pathogens, and nutrient imbalances into the soil, posing risks to plant growth and soil sustainability.

The Inefficiency of Synthetic Fertilizers

The reliance on synthetic fertilizers compounds the problem. Shockingly, as little as 20% of the nitrogen applied to agricultural land is absorbed by crops, with the remaining 80% lost to the environment. This inefficiency not only contributes to pollution but also highlights the shortcomings of our current nutrient management practices. The global nitrogen surplus—estimated at 130 million tons per year, more than double the safe threshold—further underscores the environmental risks we face, including the disruption of biogeochemical processes.

How Landfills Disrupt the Nutrient Cycle

Sending large amounts of organic waste to landfills, rather than composting it, leads to significant nutrient loss. In 2019, food waste alone accounted for 50-60% of the 242 million tons of municipal solid waste produced in China, highlighting the scale of the problem. When organic matter decomposes in landfills, it produces methane instead of enriching the soil, further exacerbating the problem.

The inefficiency of our current waste management practices is evident in the staggering amount of food waste that is generated globally—14% lost from post-harvest to retail, and 17% (approximately 931 million tons) wasted by households, the foodservice sector, and retailers. This not only disrupts the nutrient cycle but also contributes to 8-10% of global greenhouse gas emissions, pushing us closer to the planetary boundaries that define safe environmental limits.

Innovative Solutions for Sustainable Waste Management

One promising approach to managing organic waste more sustainably is valorizing it into soil amendments like compost, biofertilizer, and biochar. These methods offer a way to recover nutrients, enhance soil fertility, and improve crop productivity. For example, using food waste-based amendments can increase soil organic carbon, improve soil sustainability, and reduce the need for commercial fertilizers, which are often linked to environmental pollution.

However, the effectiveness of these soil amendments depends on proper management to avoid risks such as high sodium content and the presence of microplastics and pathogens. This is where true innovation come into play. By focusing on wet waste management at the source, Mankomb and similar initiatives can prevent contamination, ensuring that organic waste is effectively converted into valuable resources, thus closing the nutrient loop and tackling some of the most pressing climate challenges.

The Environmental Impact of a Disrupted Nutrient Cycle

When the nutrient cycle is disrupted, the consequences are widespread. Nutrient loss leads to declining soil fertility, making it increasingly difficult for plants to grow without synthetic fertilizers. This decline in soil health has a direct impact on agricultural productivity, often resulting in the overuse of fertilizers, which in turn contributes to nitrogen pollution.

The disruption of the nutrient cycle also causes broader ecosystem imbalances, affecting biodiversity and other natural processes that are critical for life on Earth. For example, in Canada, nitrous-oxide emissions have increased by roughly 30% since the 1980s, largely due to the increased use of synthetic nitrogen fertilizers, illustrating the environmental impact of a disrupted nitrogen cycle.

Sustainable Practices to Preserve the Nutrient Cycle

To combat these challenges, it is essential to adopt sustainable practices like composting at both home and community levels. Composting keeps organic matter within the nutrient cycle, enriching the soil and reducing the need for synthetic fertilizers. Regenerative agriculture, which focuses on soil health and closing the nutrient loop, also offers a promising path forward.

Additionally, waste diversion strategies such as curbside composting programs and food waste reduction initiatives are crucial. The co-digestion of municipal wastewater and food waste is another innovative approach that optimizes infrastructure use, diverts organic waste from landfills, facilitates nutrient recovery, and produces renewable energy.

The Role of Policy and Innovation

Governments play a key role in reducing organic waste in landfills and promoting composting. Innovative technologies that process organic waste more efficiently and return nutrients to the soil are emerging as vital tools in this effort. For instance, tackling the rise in nitrous oxide emissions, which have increased by 30% in Canada since the 1980s, requires coordinated global and local efforts, community engagement, and the adoption of innovative practices.

Policies aimed at reducing the use of synthetic fertilizers and encouraging sustainable agriculture practices are also critical. The global nitrogen surplus and the inefficiency of synthetic fertilizers highlight the need for stronger regulations and incentives for adopting more sustainable nutrient management practices. Sustainable alternatives for food waste management, such as transforming food waste into soil amendments, can play a significant role in improving soil sustainability and reducing the environmental impact of commercial fertilizers.

What Can We Do?

As individuals, we can adopt sustainable habits such as home composting, reducing food waste, and supporting local composting programs to reduce our organic waste footprint. Community-led initiatives around the world have shown that preserving the nutrient cycle is not just possible but also impactful. Public education and advocacy are crucial—by raising awareness about the importance of the nutrient cycle and supporting policies that promote sustainable waste management, we can make a significant difference.

Takeaway

Preserving the nutrient cycle is essential for maintaining soil health, supporting agriculture, and reducing environmental impacts. By adopting sustainable practices, supporting innovative technologies, and advocating for effective policies, we can close the nutrient loop and contribute to a more sustainable future. The question remains: will we take the necessary steps to restore balance to the natural cycles that sustain life on Earth?