SOIL EROSION, SEDIMENT YIELD, CONSERVATION STRUCTURES, AND DSS FOR SUSTAINABLE LAND MANAGEMENT ON SEMIARID RANGELAND WATERSHED
Location: Southwest Watershed Research
Title: Rainfall erosivity in Brazil: A Review
Submitted to: Catena
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: August 12, 2012
Publication Date: N/A
Interpretive Summary: Rainfall erosivity is the term used to describe the power of rainfall to cause soil erosion. Rainfall erosivity varies a lot from place to place. For example, in the United States erosivity values range from around 10 in parts of the western US to more than 700 in southern Louisiana to more than 2000 in a small part of Hawaii. This means that potential for erosion to occur also varies dramatically depending on the rainfall of a given location. While a great deal of information is available in the United States on erosivity, much less is known in other parts of the world. This study was an attempt to review all of the available information known about rainfall erosivity in Brazil. Various types of information on rainfall were accumulated and equations developed by multiple researchers were used to evaluate that information. The product of the research will allow us or others to develop a map of erosivity for the entire country of Brazil so that better conservation planning and assessment may be made in that country.
In this paper, we review the erosivity studies conducted in Brazil to verify the quality and representativeness of the results generated and to provide a greater understanding of the rainfall erosivity (R-factor) in Brazil. We searched the ISI Web of Science, Scopus, SciELO, and Google Scholar databases and in recent theses and dissertations to obtain the following information: latitude, longitude, city, states, length of record (years), altitude, precipitation, R factor, equations calculated and respective determination coefficient (R2). We found 32 studies in Brazil that used pluviographic rainfall data to calculate the rainfall erosivity. These studies were concentrated in the cities of the south and southeast regions (~ 70% of all the cities studied in Brazil) with a few studies in other regions, mainly in the north. The annual rainfall erosivity in Brazil ranged from 1,672 to 18,646 MJ mm ha-1 h-1 yr-1. The lowest values were found in the northeast region, and the highest values were found in the southeastern regions and the central-west region. We found 61 regression equations to calculate erosivity. From these equations, new studies can be developed to map the rainfall erosivity for the entire country. To this end, techniques already established in Brazil may be used for the interpolation of rainfall erosivity, such as geostatistics and artificial neural networks.