The transition towards a more circular greenhouse horticulture sector relies heavily on exploring new ways to utilize nitrogen-based fertilizers efficiently and safely. Nitrogen is a crucial nutrient for plant growth, but its natural form in the air (N2) is not directly available to plants. To make nitrogen available as a nutrient, the nitrogen atoms must be split, which requires a significant amount of energy. The most common method for this is the Haber-Bosch process, which relies on natural gas, associated with CO2 emissions and price fluctuations, making it unsustainable in the long run.
Alexander van Tuyll from Wageningen University & Research’s Business Unit Greenhouse Horticulture (WUR) emphasizes the importance of finding green alternatives to conventional nitrogen fertilization methods. One such alternative is extracting nitrogen from the air without using natural gas or reusing nitrogen from residual streams. These alternatives are being explored in collaboration with the Club of 100, a project that aims to provide a clear overview of sustainable nitrogen fertilization options for greenhouse horticulture.
One of the challenges in utilizing nitrogen from residual streams is ensuring that the fertilizer is pure and highly soluble. For crops grown in recirculating systems, like vegetables, the fertilizer must be free of contaminants such as sodium and heavy metals to ensure efficient delivery through drip irrigation systems. Bioreactors are used to purify and solubilize nitrogen, keeping contamination levels within safety limits and making the fertilizers safe for use in greenhouse horticulture.
The researchers also compared energy consumption for different nitrogen extraction methods, highlighting the energy-intensive nature of the traditional Haber-Bosch process compared to extracting nitrogen from residual streams. The White Paper aims to provide a clear comparison of these approaches to help fertilizer producers make sustainable decisions and support growers in achieving more sustainable cultivation practices.
The nitrogen project is a collaborative effort between the Business Unit Greenhouse Horticulture and Wageningen Food & Biobased Research. The research, led by Marc Lanting from Food & Biobased Research, investigates the various technologies involved in sustainable nitrogen fertilization for greenhouse horticulture.
This White Paper on nitrogen is the first in a series of publications focusing on the use of circular fertilizers in greenhouse horticulture. Future publications will address other essential nutrients such as magnesium and zinc. The circular fertilizer project is funded by the collective resources of the Club of 100, highlighting the industry’s commitment to sustainability and innovation in greenhouse horticulture.
In conclusion, exploring green alternatives to conventional nitrogen fertilization methods is essential for the transition to a more sustainable and circular greenhouse horticulture sector. By utilizing nitrogen from residual streams and other green alternatives, growers can reduce their environmental impact and improve the efficiency and safety of nitrogen-based fertilizers. Collaborative projects and research efforts, such as the one led by WUR and the Club of 100, are crucial in driving innovation and sustainability in greenhouse horticulture.
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