DETERMINATION OF SOIL ERODIBILITY BY MEANS OF TWO INDIRECT METHODS IN A WATERSHED IN THE SOUTHERN REGION OF THE STATE OF AMAZONAS, BRAZIL

Abstract

Water erosion is one of the main problems facing agriculture worldwide. It is responsible for the transport of sediments that compromise the quality and quantity of water in rivers and reservoirs, as well as for the loss of nutrients and soil organic matter, thereby causing direct damage to agricultural production and the environment. This work evaluated the erodibility of soils in the Juma watershed, located in the southern region of the state of Amazonas, through two indirect methods and assessed the soil attributes of the area that most contribute to its erodibility. Eight soil classes were identified, from which representative collections were collected randomly, and soil physical and chemical analyses were performed. Then, multiple regression and spatialization analyses of the data were performed by kriging interpolation using the Geographic Information System (GIS). It was verified that the erodibility indices obtained by both methods were strongly influenced by textural extremes (sand and/or silt); however, the Denardin method presented more adequate results. These results indicate that there is a predominance of moderate soil erodibility in the study area, as well as high and very high erodibility around the main water courses associated with soils of alluvial origin.