 Bertoni and Neto point out this condition as one of Brazil's highest environmental dangers, and a large part of them result from human activities.Soil erosion removes nutrients and causes the loss of structure, texture and the decrease of infiltration rates and water retention.Plowing and herbicides to control undesirable weeds leave the soil exposed and susceptible to erosion – either by loss of topsoil (which is richer in nutrients), or from gullies.