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WWOOFing and biofilter for the pond – Leticia Mijolaro Sartori

My name is Leticia Mijolaro Sartori, I am 21 years old and I am Brazilian.

I am finishing my bachelor’s degree in Agronomic Engineering. Before going to the farm, I did an exchange program at Wageningen University and Research in the Netherlands for six months.

After that, I decided to stay in Europe for another six months to gain experience here. In the meantime, I discovered WWOOF and Alella Green Tech. I spent a month on the farm. During that time, I had the opportunity to work with a multitude of things. There are many ongoing activities and projects that you can help and participate in while working on your main project.

Some examples of the activities I had the opportunity to help with were watering the plants, building a mud hut, a kitchen cupboard, and a chicken coop, planting lavender, pumpkins, and melons, managing the sheep, helping to organize a children’s event and talk about erosion during this event.

About my main project, we initially thought about something related to the control of a very problematic fungus for the vine, called mildew. I had the opportunity to work for a year in a plant pathology laboratory at my University in Brazil, so I have a lot of experience with plant diseases in general. However, environmental conditions were still not so favorable for the development of this fungus, which usually has its growth peak in late spring and summer.

Anyway, I collected samples and evaluated the presence of the fungus in the orchard and I was able to verify that the vines were completely healthy. Considering this and the fact that my stay on the farm would be short, we started another project. This, in turn, was related to the creation of a biofilter for the farm’s main pond.

Basically, the biofilter consists of using the plants to extract the excess nutrients in the pond, naturally present or resulting from the excreta of the fish found there. In addition to nutrient extraction, the use of plants has many other advantages. It deprives the microalgae of the nutrients they use for their growth and development, controlling them and preventing eutrophication.

In addition, the fact that they cover the surface of the water prevents sunlight from entering. This also controls algae, as it prevents them from receiving light and carrying out photosynthesis, the most essential process for staying alive. The surface cover also prevents the loss of water by evaporation in regions with a hot climate and high solar radiation, as is the case with the pond. Besides that, plants can oxygenate the water, allowing greater biodiversity as most aquatic organisms are aerobic. Plants also provide shelter and food for various animals and microorganisms, which helps maintain greater biodiversity too. Finally, they are generally used for ornamental purposes, also contributing to decoration, making the pond more visually attractive.

To develop this project, I collected some pH samples and analyzed the pond conditions to choose the plant species that would best adapt. Considering the environmental conditions and the objectives related to what you want from the pond, I came to the conclusion that the plant, popularly known as duckweed, would be the best option. There are several species of this plant that can even be used together.

Unfortunately, I did not have time to implement the system and see the development of the plants. However, everything is documented and can be used by anyone interested in the subject and who wants to continue the project.

As a result of this work, due to the extraction carried out by the plants, a decrease in the nutrients diluted in the water can be expected. This prevents the lake from going through the process of eutrophication and lack of oxygen, preventing the death of aerobic organisms and damage to the ecosystem. In addition, all the other advantages of the presence of plants already mentioned will also be added to the local ecosystem.

As an agronomist engineer, I see a lot of potential in the area. The farm already has vines, for example, which can be improved in general management and especially in fruit cutting. There are several other projects that could also be very interesting, such as improving the ponds, creating a community garden close to the volunteers’ facilities, improving the irrigation system and water collection, among others.

And, above all, it is expected to implement a large field of vegetable production, for which the presence of an agronomist engineer would be essential. Being on the farm, even for a short time, added a lot to me. I highly recommend this experience to anyone interested in agribusiness, organic agriculture, and engineering in general.