Day 11:02 pm
The tax of infiltration in arenaceous ground is bigger of what in argillaceous ground (WAR, 1998). We can consider the following types of pluvial erosion: Laminar erosion in ridges or ravinas and soil erosions. Erosion in sheet or to plate Occurs when the superficial draining is not concentrated in canals and yes if it distributes for the hillsides of dispersed form. When drawn out rains occur, the infiltration capacity of the ground is exceeded and then it starts to occur the draining. How much bigger the turbulence of waters, greater the erosive capacity. Although to be amena form of erosion, it is responsible for great damage to agricultural lands and for supplying great amount of sediment that goes to sand rivers, lakes and dams.
Ravinas Ocorre mainly in ground unproctected of vegetal covering. They are formed when the speed of the flow of pluvial waters increases, concentrating itself in filetes and they become turbulent; or still when the capacity of water storage in the surface is exceeded and then it starts to occur the formation of ridges and ravinas in the top of the ground. This type of erosion is responsible for the fast assoreamento of fertile valley lands, of the fluvial stream beds, lakes and dams, facilitating the overflow of waters of its courses and provoking floodings. Soil erosions the ravinas can go deep and reach the fretico sheet. When this happens the natural flow of the underground water starts to act as transporting of particles of deep of the ravina, solapando its base and provoking the collapse of the headboard, in the known process as remontante erosion. From there resultant feio is known as soil erosions. In accordance with Sebastio professor (2011, p.75), ' ' Booroca is a hollowing or rasgo of the ground or decomposed rock, caused for the erosion of the sheet of superficial draining or subsuperficial.' ' The deforestation, forest fires and the pisoteio of the cattle contribute directly for the sprouting of this type of erosion, associates to the type of ground and amount of rains.continue reading
This world caipira is disarticulated by the advent of the cultivation in the center-south and by the farms of cattle, as well as for the increasing urbanization and the fight and land illegal occupancy of landed property; the aorianos are immigrant of the Aores and the island of the wood, in Portugal, that if had established in the catarinense coast and river-grandense from middle of century XVIII. These colonists were agriculturists and fishing in its places of origin and, when they had fixed themselves here also had started to combine agriculture with fishes. Many arts of fish new had been introduced by these fishing in the places for where they migravam, however it fishes, it predatory and of attack by teen street gang, it became to feel between this community. Much of these fishing, as resulted of the urban expansion and the reduction of the supplies, had moved to the sector of services taking care of to the great contingent of tourists who pass vacation in the catarinense coast and river-grandense; the varzeiros that are the traditional populations that live to the edges of the rivers and fertile valleys, over all of the river San Francisco and the River Paran. Randall Rothenberg does not necessarily agree. These populations combined agricultural activities (rice plantation), extrativistas of the bush and also the activities of fish, cattle and ceramic, as well as the knowledge that had of the river and its natural resources. After the construction of the hydroelectric plants and alterations in the hdrico regimen of the advance of the sugar cane-of-sugar and the irrigated rice, these populations had had its way of transformed life; quilombolas that they are descending of the black slaves and that they survive in old farms left for great proprietors. Its social visibility is recent, fruit of the fight for the land, of which, in general, they do not possess writing. 1988 constitution guaranteed the right on the land of which they live.continue reading