Creating circular farms with seagriculture

The demand for seaweed has increased in recent years. However, this seaweed is often imported from Southeast Asia. Growing seaweed locally is more sustainable and cost-effective. After meetings between the partners, this research question emerged:

How can we realise cost-effective Ulva seaweed cultivation in land-based aquaculture and what is the quality of the cultivated Ulva for dairy feed?

This question leads to the following subquestions: 

• How can we best shape aquaculture of Ulva, is it through substrate-bound or free-floating growth and production and what are its biomass yields?
• What is the quality of cultured seaweed for animal feed compared to imported Ulva seaweed with respect to protein content and amino acid composition?
• What is the techno-economic and ecological feasibility of Ulva seaweed cultivation on land for application in dairy cattle feed?

The aim of this feasibility study is to further substantiate the seagriculture concept for manure processing and soy-free protein provision of an average Dutch dairy farm.

With the Seagriculture project, the partners expect to achieve the following results:

• new insights on Ulva aquaculture through a focused literature review
• new data on Ulva biomass growth in an open-field basin through a field experiment
• determination of the quality of animal feed based on Ulva seaweed
• techno-economic and ecological evaluation of the concept
• Networking, informing and involving dairy farmers

This project has a positive impact on dairy farmers, nature and consumers in several ways.

Firstly, the circular production of feed allows dairy farmers to become independent from soya imports. Secondly, they can drastically reduce their nitrogen emissions by using their manure as feed to grow seaweed.

By reducing soya imports for animal feed, there will be less demand for soya from South America in the long run. As a result, fewer forests need to be cut down to make room for soy fields. 

Finally, consumers can enjoy local dairy products with a lower carbon footprint.

The effectiveness of Ulva seaweed in dairy feed has been demonstrated before, but there has been no previous research on a fully circular dairy farm where the seaweed is grown locally. Not only is this a sustainable solution, it also offers a solution for farmers in relation to the nitrogen problem and soya imports. This also makes the concept financially attractive.