Índice de erosividade e fator R para Jaboticabal, SP
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Data
2019-12-12
Autores
Furtado, Sergio da Silva Fiuza
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Editor
Universidade Estadual Paulista (Unesp)
Resumo
A distribuição temporal do potencial erosivo das chuvas numa região é fundamental para a elaboração de projetos de manejo e conservação do solo e da água. O objetivo do presente trabalho foi determinar a erosividade EI30 e o fator R de Jaboticabal, São Paulo. Foram determinadas a precipitação pluvial erosiva, não erosiva e total, a erosividade média mensal EI30, a erosividade média anual - fator R da Equação Universal de Perdas do Solo, o coeficiente de chuva Rc, os padrões hidrológicos de chuvas e a frequência de ocorrência de eventos extremos. Com os resultados do Rc e do EI30, foram ajustadas equações de regressão que relacionam estes índices possibilitando a obtenção da erosividade com uso de dados diários e médios mensais de pluviometria. Foram utilizadas duas séries dados históricos de precipitação pluviográficas, compreendendo os períodos de 1971 a 1986 e de 1997 a 2013, e o período total das séries agrupadas de 1971 a 2013, totalizando 33 anos de dados. O índice médio de erosividade EI30 da série de 33 anos de dados foi 4836,56 MJ mm ha-1 h-1 ano-1, portanto, este valor é fator R da Equação Universal de Perdas do Solo para Jaboticabal - SP, classificado como de médio a alto potencial erosivo. A erosividade média mensal aumentou 59,5% no período chuvoso de 1997 a 2013, em relação ao período de 1971 a 1986. O período mais crítico de erosividade na série de 1971 a 1986, de novembro a janeiro, tinha erosividade alta, foi alterado para dezembro a fevereiro, na série de 1997 a 2013, com aumento de 29% para erosividade classificada como muito alta. O padrão de chuvas de Jaboticabal - SP aumentou de 54% para 60% da chuva do tipo avançada e reduziu de 30% para 20% de chuva do tipo atrasada, considerando os períodos de 1971 a 1986 e 1997 a 2013, respectivamente. Houve aumento de 77,27% na ocorrência de eventos individuais extremos de alta precipitação e potencial erosivo, da média de 1,37 por ano, no período de 1971 a 1986, para 2,44 por ano, no período de 1997 a 2013.
The temporal distribution of the erosive potential of rainfall in a region is fundamental for the elaboration of soil and water management and conservation projects. The objective of the present work was to determine the monthly and annual average EI30 erosivity of Jaboticabal, São Paulo. Erosive, non-erosive and total rainfall were determined, the monthly average erosivity EI30, the annual average erosivity - factor R of the Universal Soil Loss Equation, the rainfall coefficient Rc, the hydrological patterns of rainfall and the frequency of occurrence of events. In addition, the regression equations of the rainfall coefficient Rc with the EI30 erosivity index were adjusted based on data from historical series of rainfall from 1971 to 1986, from 1997 to 2013 and from 1971 to 1971. 2013, totaling 33 years. The results of the rainfall coefficient Rc and the average monthly erosivity index of the EI30 rainfall were subjected to analysis of variance as independent variables, and when there was significant difference for linear and / or quadratic regressions, the equation of the highest significant degree was defined. The average erosivity index EI30, R factor of the Universal Soil Loss Equation for Jaboticabal, SP is 4946.38 and is classified as medium to high. The average monthly EI30 erosivity increased by 59.5% in the rainy season from 1997 to 2013, compared to the same period in the series from 1971 to 1986. The most critical period of erosivity in the series from 1971 to 1986, from November to January, had erosivity. high, was changed to December to February in the series from 1997 to 2013, with a 29% increase for erosivity rated as very high. The rainfall pattern of Jaboticabal, SP increased from 54% to 60% of advanced type rainfall and reduced from 30% to 20% of late type rainfall, considering the periods from 1971 to 1986 and 1997 to 2013, respectively. There was an increase of 77.27% in the occurrence of extreme individual events of high precipitation and erosive potential, from an average of 1.37 per year, from 1971 to 1986, to 2.44 per year, from 1997 to 2013
The temporal distribution of the erosive potential of rainfall in a region is fundamental for the elaboration of soil and water management and conservation projects. The objective of the present work was to determine the monthly and annual average EI30 erosivity of Jaboticabal, São Paulo. Erosive, non-erosive and total rainfall were determined, the monthly average erosivity EI30, the annual average erosivity - factor R of the Universal Soil Loss Equation, the rainfall coefficient Rc, the hydrological patterns of rainfall and the frequency of occurrence of events. In addition, the regression equations of the rainfall coefficient Rc with the EI30 erosivity index were adjusted based on data from historical series of rainfall from 1971 to 1986, from 1997 to 2013 and from 1971 to 1971. 2013, totaling 33 years. The results of the rainfall coefficient Rc and the average monthly erosivity index of the EI30 rainfall were subjected to analysis of variance as independent variables, and when there was significant difference for linear and / or quadratic regressions, the equation of the highest significant degree was defined. The average erosivity index EI30, R factor of the Universal Soil Loss Equation for Jaboticabal, SP is 4946.38 and is classified as medium to high. The average monthly EI30 erosivity increased by 59.5% in the rainy season from 1997 to 2013, compared to the same period in the series from 1971 to 1986. The most critical period of erosivity in the series from 1971 to 1986, from November to January, had erosivity. high, was changed to December to February in the series from 1997 to 2013, with a 29% increase for erosivity rated as very high. The rainfall pattern of Jaboticabal, SP increased from 54% to 60% of advanced type rainfall and reduced from 30% to 20% of late type rainfall, considering the periods from 1971 to 1986 and 1997 to 2013, respectively. There was an increase of 77.27% in the occurrence of extreme individual events of high precipitation and erosive potential, from an average of 1.37 per year, from 1971 to 1986, to 2.44 per year, from 1997 to 2013
Descrição
Palavras-chave
EI30, Potencial erosivo da chuva, Ciência do solo, Erosão hídrica do solo, Conservação do solo