The experiment was led by agricultural engineer Ana Catarina Fontes, who over 90 days monitored the effect of the animals’ grazing on vegetation on an overgrown council-owned plot measuring 4,042 square metres in Fiães.
Using on-site measurements and also images gathered on a weekly basis by drones, she aimed to “identify how much combustible material these 26 goat sappers managed to consume in three months”. The conclusion was that “they made disappear more than 12 tons of brush that, at the start of the process, was around 1.7 metres high”.
Fontes now proposes to share the data obtained with public and private entities “to make them aware of the fact that it is not so very expensive to keep a plot clear if, after the initial intervention with machinery, the subsequent maintenance is done resorting to herds of goats” or other livestock.
Under the name ‘Back to Basics’, the agricultural engineer aims to apply the study’s results to set up her own land-clearing business using grazing animals.
“I’m not creating anything new,” she pointed out. “But this method had been forgotten and it has been demonstrated that it is economically more viable than clearing [land] using machines, which for one hectare of land can cost 1,500 to 2,000 euros every six months.”
There are also social benefits, she argues: “There was great acceptance from the community in general for the introduction of animals on the plots assessed and we concluded that people consider this method more pleasant, compared with the regular use of machines”.
The goats spent their nights in a shelter created for the purpose in an abandoned factory on the plot, and during the day they were left free to wander around the area, eating brambles, gorse and ferns. They started with the leaves and then moved on the stalks and then the main stems, leaving only young ferns because of their “high level of toxicity”.
The fact that these ferns are left behind is not an issue for forest management, Fontes said, given that the species “has a humidity rate of the order of 80% and that also represents security against fires and more protection for the soil”.
As well as the vegetation on site, the 26 goats received additional feed over the 90 days. Compared with a control group, those that grazed the plot showed significant weight gains over the period, while their droppings helped enrich the soil.
According to Emídio Sousa, mayor of Feira, the council may yet use the services of Fontes’s future company for other, similar work, or call on other enterprises to use a similar approach.