Nature > Geology and soil

As for geology, Entrimo is in the so-called centre Iberian area. According to the geological features of the municipality, Entrimo is settled inside the area Tras-os-Montes. The rocks are of granitic origin and according to its structure, position and composition they belong to the biotitic granodiorite group (last phases of the Hercynian period). A small part of the rocks are slate-type and at the foot of the Serra do Quinxo, on the bank of the reservoir Lindoso.

As for its morphology, granodiorite generates a rough relief of big “skittles” – if the grain size is thick- in order to ease when the grain decreases.

The soil that is formed from the granitic rock is sandy and much filtrated and, under the climate of Entrimo, it gives rise to clays with a limited ability to retain soil nutrients and water, what limits its fertility. Indeed, on one hand, nutrients tend to be washed by the rain, without accumulating on the soil and, on the other hand, the ability to retain water is neither very high, what leads to growth problems in vegetables during summer, when rainfall is scarce. Finally, fertility depends a lot on the deepness of the soil, which at the same time depends to a great extend on the slope. Therefore, the most fertile soil will tend to concentrate at the foot of valleys and on flat areas. On the contrary, less fertile soils will be on steep slopes. In soils with a considerable deepness and fertility, or in the vicinity of watercourses, we will find leafy species, pastures and arable lands. And there where the soil is scarce and there were erosion problems, pine trees will grow or, in case of insufficient fertility, it will be the thicket.