Modelagem do excedente de infiltração para avaliar a funcionalidade hidrológica do solo

Abstract

The soil ability to compartmentalize water in the hydrological cycle can be studied in terms of the soil physical quality and might be indicated by soil’s properties, attributes or process. Of these, the processes are more informative of soil functionality as a water compartmentalizer and therefore are better indicators of soil physical quality. However, the complexity of soil processes makes it difficult to quantify and requires the use of facilitative strategies, such as mathematics modeling. Therefore, the indication of soil hydrological functionality as a compartmentalizer of water might done by modeling of the water compartmentalization processes, especially the infiltration of water in the soil, which is the main water partitioning process in the soil profile scale. In water compartmentalization, the non-infiltrated water, which represents the water that not infiltrate in the soil and might be available for surface runoff, may be a good indicator of soil hydrological functionality. Because, besides representing the compartmentalization of water, it has the connotation of potential economic and environmental damages in the case of surface runoff. However, the use of a single non-infiltrated water value is not representative of the conditions variation of soil-plant-atmosphere system. In this case, the frequency of non-infiltrated water might be more representative indicator and for its quantification a model capable of estimating the non-infiltrated water for any condition of soil-plant-atmosphere system is necessary. In this sense, the present dissertation proposes a modeling strategy in programming algorithm to obtain the non-infiltrated water and its use to indicate the soil hydrological functionality. The model was constructed and operationalized in VBA language for the quantification of non-infiltrated water with description of subprocesses involved in the partitioning of water in the soil-plant-atmosphere system at profile scale. The application of the model and the use of non-infiltrated water to indicate soil physical quality was performed in both theoretical and natural systems. The theoretical systems were used to test the model and the capacity of non-infiltrated water evidence differences between soil profiles. The natural systems were used to identify the characteristics of each system which the most contributed to a difference in infiltration performance and the profiles with higher soil hydrological functionality. The model was named SHF and allows to calculate the non-infiltrated water in theoretical and natural environments, at soil profile scale, for distinct rain, plant, residue and soil profile conditions. The non-infiltrated water was efficient in evidencing differences between soil profiles, both theoretical and natural environments. Among the parameters used, the saturated hydraulic conductivity and the initial water content in the soil were the ones that the most contributed to the soil profiles differentiation. The indication of soil hydrological functionality by frequency of non-infiltrated water is more representative of soil profile functionality and was different than which indicated by soil properties or attributes.