Eros?o h?drica e infiltra??o de ?gua no solo em sistemas de cultivo, sob chuva simulada

Autor: ALMEIDA, Wilk Sampaio de
Jazyk: portugalština
Rok vydání: 2015
Předmět:
Zdroj: Biblioteca Digital de Teses e Dissertações da UFRRJUniversidade Federal Rural do Rio de JaneiroUFRRJ.
Druh dokumentu: masterThesis
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Inadequate soil management practices associated with bare soil are the main factors that promote hidric erosion in tropical countries such as Brazil. In this study were evaluated soil and water losses, vegetation index, water infiltration into the soil and the adjusted Kostiakov-Lewis, Horton and Philip models to estimate soil water infiltration rate in four cropping systems on a Red Ultisol. The systems studied were exposed or bare soil (SE), soybeans grown under conventional tillage (PC), soybean grown under no-tillage (NT) and established pasture without cattle trampling (PA) in six seasons. Every 20 days after the soybean?s sowing digital photographs were taken to estimate soil coverage ratio. Also, simulated rainfall at the parcels was measured using a portable sprinkler infiltrometer (InfiAsper) calibrated to apply intensity of rainfall of 60 mm h-1. Soil losses ranged from 3.10 to 11.40 and 0.03 to 0.19 Mg ha-1 h-1 in the SE and PA, while water oscillated from 300.60 to 555 and 62.8 to 229.4 m3 ha-1 h-1 in the SE and PD, respectively. Soil losses decreased with increasing vegetation cover ratio, which at the PA had a maximum value of 98.1%. The initial effect of soil under conventional tillage in cropping systems is temporary, which makes them susceptible to erosion. The models were adjusted using the volume of water that was infiltrated during the corresponding time interval. In the PD system was obtained the highest infiltration rate (TIE). There was no difference between the SE and PC TIE. The best fit found is for the Horton?s model in systems with vegetal cover and without soil tillage.
As pr?ticas inadequadas de manejo do solo associadas ? condi??o de solo descoberto s?o os principais fatores que intensificam a eros?o h?drica em pa?ses de clima tropical como o Brasil. Neste estudo foram avaliadas perdas de solo e de ?gua, o ?ndice de cobertura vegetal, a infiltra??o de ?gua no solo e o ajuste dos modelos Kostiakov-Lewis, Horton e Philip para estimativa da taxa de infiltra??o de ?gua no solo em quatro sistemas de cultivo em um Argissolo Vermelho distr?fico. Os sistemas estudados foram solo exposto ou descoberto (SE), soja cultivada sob preparo convencional do solo (PC), soja cultivada sob plantio direto (PD) e pastagem estabelecida sem pisoteio animal (PA) em seis ?pocas. A cada 20 dias a partir da semeadura da cultura da soja foram tomadas fotografias digitais para estimativa do ?ndice de cobertura do solo e tamb?m simuladas chuvas nas parcelas em campo com o infiltr?metro de aspers?o port?til (InfiAsper) calibrado para aplicar intensidade de precipita??o de 60 mm h-1. As perdas de solo variaram de 3,10 a 11,40 e 0,03 a 0,19 Mg ha-1 h-1 no SE e PA, ?gua de 300,60 a 555 e 62,8 a 229,4 m3 ha-1 h-1 no SE e PD, respectivamente. As perdas de solo diminu?ram com o aumento do ?ndice de cobertura vegetal, que em PA teve valor m?ximo de 98,1%. O efeito inicial do preparo convencional do solo nos sistemas de cultivo ? tempor?rio, o que os torna suscept?veis ao processo erosivo. Os modelos foram ajustados com os dados de volume de ?gua infiltrada por intervalo de tempo correspondente. No sistema PD foi obtida maior taxa de infiltra??o est?vel (TIE). N?o h? diferen?a na TIE do SE e PC. O melhor ajuste verificado ? para o modelo de Horton em sistemas com cobertura vegetal sem revolvimento do solo.
Databáze: Networked Digital Library of Theses & Dissertations
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