?ndices de desagrega??o e par?metros de chuva intensa no Estado do Rio de Janeiro e efeito da chuva simulada na eros?o h?drica e infiltra??o de ?gua no solo

• Autor(a) principal: Almeida, Wilk Sampaio de
• Data de Publicação: 2018
• Tipo de documento: Tese
• Idioma: por
• Título da fonte: Biblioteca Digital de Teses e Dissertações da UFRRJ
• Texto Completo: https://tede.ufrrj.br/jspui/handle/jspui/5472
• topic: Simulador de chuvas; Processo erosivo do solo; Perda de solo e de ?gua; Chuvas intensas; Taxa de infiltra??o; Rainfall simulator; Soil erosion process; Soil and water losses; Intense rainfall; Infiltration rate; Agronomia

The lack of rainfall information is the main factor limiting the characterization of erosive potential of a given region and estimation of critical rainfall for use in the design of hydraulic works. In addition, inadequate soil management practices intensify the process of water erosion and infiltration of water into the soil. In this study, the relationships between precipitations of different durations (coefficients of disaggregation) were estimated; the parameters of intense rainfall equations for different localities of State of Rio de Janeiro; erosion was evaluated in a Argissolo Vermelho-Amarelo Distr?fico t?pico (Rhodudults, according the Soil Taxonomy) under conventional tillage (two harrows and a grader) and different combinations of intensities (IP) and durations (Dur) of simulated rainfall of equal erosivity; soil water infiltration measured by sprinkler infiltrometer and concentric rings was measured; and the adjustment of the Kostiakov-Lewis, Horton and Philip models was performed to estimate the infiltration rate. In the study of extreme rains, maximum annual series of 5 min to 240 min were considered, associated to return periods of 5 to 100 years. The mean rainfall ratios vary from 0.40?0.10 to 1.04?0.02, with higher values for the Southern Fluminense mesoregion. The relationships between rains obtained for the localities of Rio de Janeiro are higher than those observed in other regions of Brazil. The intensity-duration-frequency relations have low variability between studied locations and the highest values of the parameters k, a, b and c were found, respectively, in the Metropolitana, Baixadas Litor?neas and Centro Fluminense regions. As for water erosion and infiltration studies, it was found that in the condition of upturned soil and without surface cover, sediment yield ranged from 2.17 g m-2 to 6.12 g m-2, respectively in the treatments IP 52,9 and Dur 78 min and IP 44.6 mm h-1 and Dur 106 min. In addition, runoff ranged from 17.07 mm to 30.53 mm, respectively in the IP 53.5 mm h-1 and 76.5 mm h-1 treatments. In this case, a higher stable infiltration rate (SIR) was measured with the concentric ring infiltrator in comparison to rates obtained with a spray infiltrometer. Rainfall durations and intensities changed sediment yield, but no significant difference in runoff was observed. Otherwise, for soil with corn straw on the surface, sediment yield ranged from 1.89?1.26 g m-2 to 4.02?2.66 g m-2 and runoff ranged from 16.9?8.74 mm at 32.63?10.67 mm. In this condition, rainfall durations and intensities did not significantly alter sediment yield and surface runoff. The infiltration of water measured with the concentric rings has a greater variability, with an SIR quantified in the duration 78 min is equal to the SIR obtained with the sprinkler infiltrometer, and these are greater than the rates of the durations 106 and 60 min of the concentric rings. Higher errors in estimating infiltration rates by the Kostiakov-Lewis, Horton and Philip models were found when using concentric rings to measure infiltration, however, in the condition in the presence of ground cover, model performance was similar.