Author(s): Ramos, Tiago Cunha Brito
Date: 2014
Persistent ID: http://hdl.handle.net/10400.5/7345
Origin: Repositório da UTL
Subject(s): brackish waters; nutrient leaching; pedotransfer functions; reactive transport modeling; soil hydraulic properties
Doutoramento em Engenharia dos Biossistemas - Instituto Superior de Agronomia
Modeling has become an essential tool for implementing better irrigation and fertilization practices. The HYDRUS software package is currently one of the few models capable of considering multicomponent geochemistry and evaluating multiple environmental problems in an integrated way. The model was used to simulate water movement and solute transport in two complex experiments carried out under field conditions, between 2004 and 2010. The field experiments were helpful to identify the main physical and chemical processes influencing soil water flow and multicomponent solute transport in soils irrigated with saline waters. They were further useful for evaluating different irrigation water quality and fertilization scenarios while considering soil salinization/sodification risks, root nutrient uptake, nutrient leaching, and crop yield. HYDRUS proved to be a powerful tool for establishing sound irrigation policies. However, the considerable demand on input data, namely, soil hydraulic properties, has been limiting its use (and other reactive transport models). Different pedotransfer functions (PTFs) were thus established to indirectly estimate soil hydraulic properties from the soil information available in the PROPSOLO database. A set of class-PTFs were developed to estimate water retention properties after grouping data by soil texture, soil horizon, and bulk density. A different procedure was also presented to estimate water retention properties from particle size distribution using the soil texture triangle and ordinary kriging. Finally, a set of PTFs were established for Cape Verde soils. All these PTFs may have multiple applications in irrigation management and watershed modelling. However, it is still necessary to further extend those PTFs to other regions of Portugal and Cape Verde, and to gain more knowledge on the hydraulic conductivity functions of those soils so that they can be used in reactive transport modeling
