WATER EROSION IN EUCALYPTUS FOREST IN THE MUNICIPALITY OF OTACÍLIO COSTA (SC)

ABSTRACT Water erosion is the main factor of degradation and reduction of the productive capacity of the soil, requiring management operations that minimize water and soil losses and at the same time maximize crop productivity. The research aimed to quantify losses by water erosion and, in the runoff water, determine the levels and total losses of P and K during the development of Eucalyptus (Eucalyptus benthamii). Eucalyptus was planted in three types of soil preparation: minimum preparation in the direction of the slope, minimum preparation in the contour of the slope, and semi-mechanized preparation, in an experiment in southern Brazil on a Haplic Dystrudept soil. We observed that the mechanical preparation of the soil carried out in the direction of the slope is less effective in controlling soil losses than the mechanical carried out perpendicularly to the slope and also less effective than the manual in pits, in which the soil losses are equivalent to 10% of those that occur in the direction of the slope. As for the control of water losses, manual preparation in pits is more effective than the two mechanized preparations. The greatest losses of soil occur in the fall, with losses 27 times greater in relation to the other seasons of the year, and the greatest losses of water occurred in the mechanized preparation perpendicular to the slope and in the manual preparation. Water losses vary less than soil losses, regardless of the type of soil preparation and the season. The losses of phosphorus and potassium by the Runoff water vary with the contents in the soil, with the type of soil preparation and with the moment of evaluation.