Who says rainy season, says erosion, one of the major natural risks facing the island. Deforestation is one of the primary causes. “When trees are cut down, violent rain directly attacks the soil. The canopy is no longer present to cushion its force.”underlines Michel Charpentier, president of the Les Naturalistes association. During this season, the soils are even more vulnerable because they are often bare, a time when farmers take advantage of it to plant cassava and banana trees. These crops, moreover, very present in Mayotte, do not retain water. ” Bananas are not trees, so rain seeps into the ground very easily. In a sloping field, it descends very quickly to a ravine, then to the lagoon. ”
Avoid work during the rainy season
Each year, around 25,000 tonnes are dumped in the jewel of Mayotte. “ This handicaps the coral reefs which find themselves silted up. describes the representative of the Naturalists, during the first round table of this Environment Week, this Monday morning. The brown-orange color that can be observed on the coasts after the rains corresponds to the sediments that have flowed. Problem: in the lagoon, the currents are not powerful enough to sweep away the mud. Beyond deforestation, earthworks are also responsible for erosion. When individuals undertake work, “you should not leave the earth exposed to the rain, simply putting a tarpaulin over the pile already solves part of the problem “, explains Floriane Ben Hassen, head of the Mahor branch of Météo France. She also recommends not “not do them in the rainy season because currently they arrive in the lagoon or in the rivers”.
To avoid erosion, several practices are recommended, on how to plant crops for example, “by breaking the slopes to ensure that the earth does not go away”, iillustrates the head of Météo France. “Ultimately, it is more beneficial in terms of agricultural yield. When we burn, we have the impression that it is more interesting but that is not true. The first year, we have inputs of phosphate and nitrates interesting, but the second year, the soil is extremely poor because when you burn the land, all the life there is killed.”. With mulching, the yield is greater. In return, “this requires a lot more work”agrees Floriane Ben Hassen. While it is very tedious because it requires reducing the plants into small pieces to spread them on the ground, according to the specialist, “we should develop a sector for mulching in Mayotte”.
Practical advice
To adopt practices that preserve the soil, the Leselam project (fight against soil erosion and siltation of the lagoon in Mayotte) was launched on the archipelago. It made it possible to publish practical advice flyers to the general public, one dedicated to agriculture, another on house construction and another on ravines and gardens. It can be downloaded online but it is also possible to pick them up at the geological and mining research office (BRGM) located in Hauts-Vallons behind the Mayotte la 1ère premises or at the Naturalistes headquarters in Dembéni.
By Mayotte Hebdo
