Water Infiltration Experiments Research Articles

ALTERAÇÕES NA INFILTRAÇÃO DE ÁGUA EM LATOSSOLOS DEVIDAS À INCORPORAÇÃO CONTROLADA DE RESÍDUO INDUSTRIAL DE SILICATOS

No presente trabalho foram efetuados experimentos de infiltração de água em colunas de latossolos não saturados. Foram utilizados um Latossolo Vermelho Amarelo, um Latossolo Vermelho Escuro e um Latossolo Roxo, tratados com um resíduo de silicatos proveniente de uma indústria do município de Rio Claro, SP. O resíduo foi incorporado a cada solo em taxas de 1%, 2%, 5% e 10% , em peso. Uma coluna de cada solo sem resíduo foi usada como controle. As posições da frente de molhamento em função da raiz quadrada do tempo de infiltração e as umidades iniciais e de saturação de cada coluna foram medidas. Os resultados mostraram que o aumento da concentração do resíduo incorporado, provocou a diminuição da velocidade da frente de molhamento. A principal conclusão é que a adição do resíduo diminuiu a infiltração da água nos solos, ao mesmo tempo em que aumentou a sua retenção, e isto é benéfico para a agricultura. Do ponto de vista ambiental, o aproveitamento do resíduo industrial como condicionador de
 solo também é benéfico, dentro dos limites do estudo, pois representa uma alternativa ao armazenamento do mesmo ou ao simples descarte em aterro sanitário.

Resistivity and percolation study of preferential flow in vadose zone at Bokhorst, Germany

Traditional nondestructive resistivity techniques have been applied in combination with tracer displacement and conventional soil moisture recording methods [i.e., buried tensiometer and time domain reflectometry (TDR)] for studying flow processes at an arable site in Bokhorst, Germany. Three water infiltration experiments were carried out using tap water spiked with a nonreactive tracer at different concentrations. The study aimed at exploring the capabilities of these combined techniques for tracing the preferential movement of water in the uppermost 1.5 m of the highly heterogeneous vadose zone. The results illustrate that the applied tensiometer and TDR techniques can detect the relatively fast flow process at their position points and thus only tentatively trace the preferential flow. The additional application of the resistivity method can trace the preferential flow paths continuously along the plane of measurements. The results of the individual applied methods complement and confirm each other.

Analytical Expression for Soil Water Diffusivity Derived from Horizontal Infiltration Experiments

AbstractA technique is developed that utilizes a rational function θ = (A1 + A3λ)/(1 + A2λ) to fit water content (or other liquid) profiles resulting from horizontal infiltration as used in the Bruce‐Klute method for determining soil water diffusivity. In the above function, θ is water content (L3 L−3), λ is the Boltzmann variable, and A1, A2, and A3 are constants. The Boltzmann variable, λ, is equal to xt‐0.5, where x is the distance from the inlet of a horizontal soil column and t is time from the commencement of liquid imbibition. The function is easily fit to experimental data by either linear or nonlinear regression techniques and leads to analytical expressions for sorptivity and soil water diffusivity without further numerical approximation or fitting. If boundary conditions are specified, only one of the three coefficients is left to be determined. The rational function provided excellent approximations to liquid distribution for water and alcohol horizontal infiltration experiments in this study and is adequate for representation of experimental data of several other researchers. An example is included to illustrate that the approach is also applicable to determination of diffusivity for the hot‐air method.