Dynamics and spatial aspects of erodibility in Indian Black Earth in the Amazon, Brazil

Abstract

Soil erosion generally causes environmental and economic damage to agricultural systems, representing one of the biggest management problems for agriculture. Therefore, understanding the behavior of the erosive process is indispensable for the diagnosis of best conservationist practices of use and management of agricultural resources. The aim of this paper was to characterize the dynamics and spatial aspects of erodibility, its indicators and to evaluate the applicability of the prediction equations of soil loss proposed by Denardin (1990) and Flanagan and Livingston (1995) for cultivated and natural Indian Black Earths (IBEs). Grids with 88 georeferenced sampling points were established for soil sampling at a depth of 0.0–0.20 m. Laboratory analyzes were performed to determine soil particle size and soil organic matter (SOM) analysis. The erodibility factors were calculated and applied univariate analysis, geostatistics and multivariate techniques. Cultivated IBEs exhibit moderate to high soil loss rates even in low slope relief, mainly by runoff. The dynamics of the erodibility factors behave under moderate spatial dependence between the attributes, with high range values and moderate relief influence, indicating high spatial variability, showing the tendency of values of soil losses similar to distances between 15 and 69 m. However, texture and organic matter were the main indicators of erodibility, since medium texture IBEs tend to increase the global and interril erodibility values, and under sandy texture tend to increase erodibility in gully. The increase in SOM elevates erodibility and interril due to the high amount of pyrogenic coal with high capacity to retain water. Therefore, we recommend the adoption of management practices that reduce erosion processes, and mainly avoid the loss of mineralized SOM to maintain crop sustainability.