WATER EROSION UNDER THREE TILLAGE METHODS IN A CULTIVATION OF Eucalyptus benthamii

摘要

ABSTRACT Soil tillage influences the development of forests planted in the initial phase, which affects some hydrological processes and water erosion. The objective of this study was to quantify the water losses (WL) and soil losses (SL) by water erosion, between the second and third years of eucalyptus ( Eucalyptus benthamii) crop, in an experiment located in southern Brazil, on a Humic Dystrudept. Was study three soil tillage treatments: i) subsoiling in downslope direction (SD); ii) subsoiling in contour on the slope (SC); iii) manual holes (MH). The plots had a dimension of 12 x 24 m, being the slope-wise length the greatest, monitored by tanks placed at the lower end for runoff collection. Runoff volume measurement and sampling for subsequent calculation of WL and SL was carried out weekly, corresponding to the rains accumulated during the week. The crop of eucalyptus in SD treatment, weakened the soil as to the water erosion in relation to the crop made in SC and in MH; the difference was 25% for the WL and 53% for the SL. Eucalyptus reforestation played an important role in the control of water erosion, regardless of the type of soil tillage. The SL due to water erosion were more influenced than the WL, regardless of the type of soil crop used. WL and SL are related to each other and to rainfall height in positive linear relationship, regardless of the type of soil preparation used for eucalyptus planting.