Perdas de solo, ?gua e nutrientes em um argissolo vermelho-amarelo sob diferentes padr?es de chuva simulada

• Ano de defesa: 2007
• Autor(a) principal: Oliveira, Jo?o Ricardo de
• Orientador(a): Carvalho, Daniel Fonseca de
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal Rural do Rio de Janeiro
• Programa de Pós-Graduação: Programa de P?s-Gradua??o em Agronomia - Ci?ncia do Solo
• Departamento: Instituto de Agronomia
• País: Brasil
• Palavras-chave em Português: eros?o h?drica; enxurrada; simulador de chuva
• Palavras-chave em Inglês: hydric erosion; rRun-off; rainfall simulator
• Área do conhecimento CNPq: Agronomia
• Link de acesso: https://tede.ufrrj.br/jspui/handle/tede/259

Few researches developed in Brazil have studied rain intensity effect in soil erosion process. The rain characteristics change from place to place (region to region) and during its events. For this reason, in studies using rain simulators, adoption of only one rainfall pattern with constant precipitation intensity, may not represent the actual regional rainfall conditions. The objective of this study was to determine the soil, water and nutrients losses in a Yellow-red Ultisol under two soil coverage conditions, and four different rainfall patterns. The experiment was conducted in Embrapa Agrobiologia experimental field, located at Serop?dica municipality, Rio de Janeiro State, Brazil. Treatments consisted in application of simulated rains using variable rainfall intensity classified in different patterns as: advanced (AD), intermediate (IN), delayed (DE), and constant (CT). The rainfalls had duration of 60 minutes, with a total applied layer of 30 mm, and a peak of 110 mm h-1, for the variable intensity standards. Two sets of simulated rain tests were carried: one on soil prepared with conventional tillage in the direction of slope, and another on soil after corn planting on the residue of a previous crop. The plots were delimited by steel plates with 0.8m width and 1.0m length, placed in the soil with the biggest side along the slope direction. For rainfall application, it was used a portable rainfall simulator, properly calibrated and in conditions of reproducing adequately the natural occurrence rainfall pattern. Although there was no statistical difference, it was possible to verify that in the soil without cover the rainfall pattern DE provided soil losses higher than CT, AD and IN, in 61.6%, 46.4% and 13.6%, respectively. As for the soil with covering, rainfall pattern IN provided the biggest soil losses, however, it only exceeded the patterns AD and DE in 19.0% and 4.7%, respectively. The water losses presented similar behavior to soil losses, and in soil without cover, the rainfall pattern DE presented a run-off superior to the AD, IN and CT patterns, of about 42%, 19% and 19%, respectively. The rainfall patterns AD, IN and DE provided higher values of soil and water losses than CT, which did not provide run-off and consequently no losses when the soil was covered. The rainfall patterns did not influence the nutrients losses in the water runoff, independently of the covering condition. The absolute nutrients losses were largest in the exposed soil, due to largest soil and water losses in this condition. The nutrients losses in the run-off suspension were highest, showing that, in the conditions of the experiment, this is the preferential way. The soil cover with corn residues reduced substantially the soil, water and nutrients loss ratios, indicating that the mulch helps, in an effective way, the erosion control, mainly in soils slopes that are cultivated.