Perdas de solo e índices de vegetação: proposta metodológica para a determinação do fator C (MEUPS) em pastagens e cana-de-açúcar
Arquivos
Data
2016-01-22
Autores
Corrêa, Edvania Aparecida [UNESP]
Título da Revista
ISSN da Revista
Título de Volume
Editor
Universidade Estadual Paulista (Unesp)
Resumo
No Brasil, poucos são os estudos sobre a estimativa de perdas de solo em cana-de-açúcar e sobre o levantamento do fator C da EUPS em cultivos alocados em paisagens com diferentes potenciais naturais à erosão. Também, no contexto mundial, poucos são os estudos que propõem metodologias alternativas para a determinação do fator C em climas tropicais. Assim, o objetivo desta pesquisa foi o de elaborar um procedimento metodológico para a determinação do fator C a partir da quantificação das perdas de solos e índices de vegetação em pastagens e cana-de-açúcar. Foram utilizados dados multissensores correlacionados aos valores do fator C estimados em 11 parcelas de monitoramento de erosão. As parcelas foram instaladas na bacia hidrográfica do córrego Monjolo Grande (Ipeúna/SP) e na bacia hidrográfica do ribeirão Jacutinga (Rio Claro/SP). Estas bacias apresentam semelhanças quanto às dimensões em área e uso da terra e variabilidade quanto às características pedológicas e de relevo. Em todas as parcelas com pastagens, as perdas de solo foram inferiores a 1,5 t ha-1 ano-1 e o fator C foi de 0,1. Mesmo em condições diversas de paisagem, as gramíneas presentes nas áreas de pastagens se comportaram de maneira similar frente aos processos erosivos. Por outro lado, verificou-se diferenças nas perdas de solos nas parcelas com cana-de-açúcar localizadas em ambas as áreas de estudo. Nos solos argilosos da bacia hidrográfica do ribeirão Jacutinga as perdas variaram de 0,8 a 2,76 t ha-1 ano-1. Já nos solos arenosos da bacia hidrográfica do córrego Monjolo Grande as perdas variaram de 49 a 84,8 t ha-1 ano-1. Assim, as diferenças nas perdas de solo em canaviais são derivadas das condições físicas de cada paisagem. Os valores do fator C nos canaviais variaram de 0,13 a 0,23 para a bacia hidrográfica do ribeirão Jacutinga e de 0,41 a 0,43 para a bacia hidrográfica do córrego Monjolo Grande. Assim, no contexto regional estudado, a expansão e o cultivo de cana-de-açúcar é realizado indistintamente, não considerando as condições de fragilidade natural de cada ambiente. Os dados de perdas de solo obtidos em campo correlacionados aos dados de sensoriamento remoto proporcionaram a criação de uma metodologia de determinação do Fator C. A utilização desta metodologia possibilitou a melhoria da modelagem da MEUPS em eventos individuais de chuva em ambas as áreas de estudo.
In Brazil, there are few studies on the estimation of soil losses in sugarcane and acquisition the factor C in the USLE in landscapes with different potential natural erosion. Also, in the global context, there are few studies that propose alternative methods for the extraction of Factor C in tropical climates. The objective of this research was to develop a preliminary methodological procedure to extract the factor C for pasture and sugarcane. Multisensor data correlated to the Factor C values estimated at plots were used. The plots were installed in the watershed of the stream Monjolo Grande (Ipeúna / SP) and Jacutinga (Rio Claro / SP). These basins have similarities as to the area and land use and variability as to the soil and relief. In all plots with pasture, soil losses were less than 1.5 t ha-1 yr -1 and C factor was 0.1. Even under various conditions of landscape, grasses present in pasture areas behaved in a similar way to the front erosion. On the other hand, there are differences in the losses of soil in the plots with sugarcane located in both study areas. In clay soils of the watershed of Jacutinga creek losses ranged from 0.8 to 2.76 t ha-1 yr-1 . In the sandy soils of the watershed stream Monjolo Grande losses ranged from 49 to 84.8 t ha-1 yr-1 . Thus, differences in soil loss in sugarcane fields are derived from the physical conditions of each landscape. The values of the C factor in the cane fields ranging from 0.13 to 0.23 for the watershed of the Jacutinga creek and 0.41 to 0.43 for the watershed stream Monjolo Grande. Thus, in the regional context studied, the expansion and sugarcane cultivation is done indiscriminately, without considering the fragility natural conditions of each environment. The data obtained in soil losses related to the field of remote sensing data led to the creation of a methodology for determining factor C. The use of this methodology improve the modeling of MEUPS in individual rainfall events in both study areas.
In Brazil, there are few studies on the estimation of soil losses in sugarcane and acquisition the factor C in the USLE in landscapes with different potential natural erosion. Also, in the global context, there are few studies that propose alternative methods for the extraction of Factor C in tropical climates. The objective of this research was to develop a preliminary methodological procedure to extract the factor C for pasture and sugarcane. Multisensor data correlated to the Factor C values estimated at plots were used. The plots were installed in the watershed of the stream Monjolo Grande (Ipeúna / SP) and Jacutinga (Rio Claro / SP). These basins have similarities as to the area and land use and variability as to the soil and relief. In all plots with pasture, soil losses were less than 1.5 t ha-1 yr -1 and C factor was 0.1. Even under various conditions of landscape, grasses present in pasture areas behaved in a similar way to the front erosion. On the other hand, there are differences in the losses of soil in the plots with sugarcane located in both study areas. In clay soils of the watershed of Jacutinga creek losses ranged from 0.8 to 2.76 t ha-1 yr-1 . In the sandy soils of the watershed stream Monjolo Grande losses ranged from 49 to 84.8 t ha-1 yr-1 . Thus, differences in soil loss in sugarcane fields are derived from the physical conditions of each landscape. The values of the C factor in the cane fields ranging from 0.13 to 0.23 for the watershed of the Jacutinga creek and 0.41 to 0.43 for the watershed stream Monjolo Grande. Thus, in the regional context studied, the expansion and sugarcane cultivation is done indiscriminately, without considering the fragility natural conditions of each environment. The data obtained in soil losses related to the field of remote sensing data led to the creation of a methodology for determining factor C. The use of this methodology improve the modeling of MEUPS in individual rainfall events in both study areas.
Descrição
Palavras-chave
Cobertura do solo, Sensoriamento remoto, Parcelas de monitoramento de erosão, Plots, Remote sensing, Soil cover