Patrik Bertschi


Reading time: approx 4 min.

The nitrogen cycle: a path to sustainable agriculture

The nitrogen cycle plays a central role in sustainable agriculture. The current challenges surrounding this cycle are key issues that concern us today more than ever.

Historical development of the nitrogen cycle

The revolution in the fertiliser industry began in 1909 with Fritz Haber, who fixed nitrogen from the air. This groundbreaking discovery made it possible to synthesise ammonia, which led to an enormous increase in agricultural productivity. This development was a direct response to the impending hunger crisis caused by population growth.

Ecological effects of fertiliser use

However, the intensive use of fertilisers also caused significant ecological problems. The release of large quantities of nitrogen into water bodies promoted the growth of algae, which led to oxygen-depleted “dead zones” in aquatic ecosystems. These zones have become a global phenomenon. In addition, the use of synthetic nitrogen fertilisers has contributed to the release of nitrous oxide (N2O), a potent greenhouse gas, and has led to a decline in soil biodiversity.

Outlook: Natural alternatives and independence

The search for natural fertilisers is becoming increasingly important in order to reduce dependence on synthetic fertilisers and make the nitrogen cycle more efficient. Insect fertiliser, obtained regionally from food waste, is coming into focus as a promising alternative.

Insect fertiliser is characterised by its unique properties. In contrast to conventional synthetic nitrogen fertilisers, this organic fertiliser offers a controlled release of nitrogen. This means that the nitrogen is released to the plants more slowly and over a longer period of time. Although this delayed availability of nitrogen could be seen as a limitation in phases of high demand, it enables a more sustainable and even supply of nutrients to the plants, which in turn reduces the environmental impact. Depending on soil moisture and plant type, a long-term release of nitrogen is even highly desirable.

In addition, insect fertiliser has an equivalent ratio of nitrogen, potassium and phosphorus, as well as a high proportion of dry matter, which results in a rich macronutrient content. This composition makes insect fertilisers an attractive alternative, especially in sustainable cultivation systems. The integration of insect fertilisers into a comprehensive fertiliser management system could help to meet both the short and long-term nutritional needs of plants. When combined with other fertilisers or agricultural practices, it offers an effective solution for promoting environmentally conscious and sustainable agriculture.

The effect of chitin on plants

The insect larvae moult a total of six times during the conversion of food waste into high-quality fertiliser. In doing so, they shed their old skin, which can be found in the fertiliser in the form of chitin. This has a versatile effect. On the one hand, it stimulates the chitin-degrading microflora to increase their activity and consequently their population. At the same time, it stimulates the plants’ defence reactions, which makes the plants more resistant to chitinous pathogens (e.g. fungi and insects) and promotes the growth of healthy and strong shoots.

SmartBreed and the nitrogen cycle

SmartBreed offers an innovative example of the application of the nitrogen cycle. SmartBreed uses a unique recycling system based on the utilisation of organic waste. Soldier fly larvae are used to process organic residues. These larvae convert waste into high-quality protein that can be used as animal feed. The nitrogen from the waste is kept in circulation efficiently and regionally.


The nitrogen cycle is a decisive factor for sustainable development in agriculture. Companies such as SmartBreed, which use innovative approaches to close the nitrogen cycle, play an important role in promoting environmentally friendly and efficient agriculture. These developments are crucial to minimising the environmental impact of agriculture while ensuring food security. The use of natural alternatives and the implementation of closed-loop systems are not only ecologically beneficial, but also offer economic opportunities.

Switching from synthetic fertilisers to natural, recyclable methods is a decisive step towards a more sustainable future.


Daniel G√§rttling, Hannes Schulz, “Compilation of Black Soldier Fly Frass Analyses”, in “Journal of Soil Science and Plant Nutrition”, received on 12 August 2021, accepted on 15 November 2021.

Patrik Bertschi


Reading time: approx 4 min.