Infiltração de água no solo sob diferentes perfis de precipitação

• Autor(a) principal: Zonta, João Henrique
• Data de Publicação: 2011
• Tipo de documento: Tese
• Idioma: por
• Título da fonte: LOCUS Repositório Institucional da UFV
• Texto Completo: http://locus.ufv.br/handle/123456789/691
• topic: Modelagem; Infiltração; Encrostamento; Modeling; Infiltration; Crusting; CNPQ::CIENCIAS AGRARIAS::ENGENHARIA AGRICOLA

The soil water infiltration is an important component of the hydrological cycle and is influenced by several factors related to soil and rainfall. The objectives of this work were to evaluate the influence of the successive application of different precipitation patterns in bare and covered soil, in order to quantify its effect on the formation of soil crusting, and consequently in the soil water infiltration rate; and evaluate the performance of the of Green-Ampt-Mein-Larson (GAML) and GAML modified by Moore (1981) models, in the simulation of infiltration process in soils with soil crusting. For each rainfall pattern (constant, exponential decreasing, double exponential early and late) we applied three successive precipitations in 24 h intervals, with an average depth of 55 mm. In the simulation of the infiltration process, was proposed to include the superficial layer of soil crusting on the input parameters of the model. For this, in the GAML model the value of hydraulic conductivity in the transmission zone (Kt) was considered equal to the stable infiltration rate (Tie) obtained in bare soil, and equal to Kt*, which equals Tie (coverage soil) multiplied by the factor f, which expresses the decay of the Tie as a function of cumulative rainfall kinetic energy (Ec), ie, the value of Kt varying over time. For the model of GAML modified by Moore (1981), it was proposed that the surface layer (crust) had a thickness of 5 mm and saturated crust hydraulic conductivity (Kc) determined from experimental data, and also equal to 10 and 25% of saturated hydraulic conductivity (K0). The influence of rainfall patterns and successive rainfall in infiltration rate was evaluated by graphs, variance analysis and mean test. The determination of the best combinations of input parameters of the GAML and GAML modified by Moore (1981) models were evaluated using the concordance index (c). It was found that the different rainfall patterns did not affect the soil water infiltration rate, both for the bare and coverage soil, which is influenced only by successive applications, with lower values of infiltration rates obtained in the 2nd and 3rd applications. This behavior can be explained because the rainfall cumulative kinetic energy has the same magnitude for both rainfall patterns. The decrease in infiltration rate in bare soil was due to formation of a superficial soil crust, formed as early as the 1st application. A Tie in bare soil declined by 75% if compared to Tie in covered soil. The f factor was described by an exponential equation. In the ix simulation of infiltration process for the 1st application of simulated rainfall in dry soil and with high soil water infiltration capacity, the model GAML with the value of Kt = Tie, determined in soil coverage, obtained good results, with performance better than good in 87.5% of cases, considering the four precipitation patterns used. For the 2nd and 3rd applications of simulated rainfall, in moist soil and soil crusting, the combinations that have not considered the soil crusting did not showed good results, overestimated Ti and I over time, regardless of precipitation patterns used. The best results were obtained using Kt equal to Tie determined in bare soil and equal to Kt = Kt*, while in Model GAML modified by Moore (1981), the best results were obtained with the Kt value of the crust equal to 10 and 25% K0, with performance by the c index better than good in 100% of the cases for both combinations. The GAML model with modifications in yours input parameters was suitable for the simulation of the water infiltration process for all precipitation patterns applied. For soils with soil crusting, the effect of this layer should be added in the input parameters of the model to obtain good results.