Técnica da TDR na estimativa da umidade e condutividade elétrica de solo irrigado com água residuária da suinocultura

• Autor(a) principal: Soncela, Rosimaldo
• Data de Publicação: 2010
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: Biblioteca Digital de Teses e Dissertações do UNIOESTE
• Texto Completo: http://tede.unioeste.br:8080/tede/handle/tede/311
• topic: Reúso de água; Calibração; Umidade volumétrica; Solo - Salinidade; Água residuária (suinocultura); calibration; soil salinity; volumetric humidity; water reuse; CNPQ::CIENCIAS AGRARIAS::ENGENHARIA AGRICOLA

The swine waste water (SWW) application in soil has become an alternative fertilizer for soil and used as a water reuse. However, special attention must be given to the amount of salt content in such water since succeeding applications can stimulate the saltishness process on soil, which can ask for an indispensable monitoring of salt content in soil. The time-domain reflectometry (TDR) allows for a continuous and simultaneous monitoring of water content and apparent electric conductivity on soil (AEC), in order to make feasible the indirect determination of electric conductivity of soil solution, which can estimate salt content in the soil. Nevertheless, there is a need to obtain and calibrate a model for each type of soil. Thus, this trial aimed at obtaining a volumetric humidity calibration model for a typical Distroferric Red Latosol, as well as studying this technique viability to indirectly determine the electrical conductivity in a soil solution using an empiric equation for the TDR Trase 6050X1 devise. Calibration was performed under laboratory conditions, with deformed samples of the studied soil, conditioned in columns, with a 0.0078 m3 volume. TDR hand-made probes, with three 0.20m-long shafts, were vertically installed in the soil columns, five probes per column, totaling 16 columns. The weighing answers were obtained by digital scales and daily readings with the TDR equipment. To indirectly determine soil solution electric conductivity, deformed and saturated samples were used and saturated with SWW at 0, 10, 20, 40, 60, and 80 liters with a soil volume of 0.0225 m3. The SWW was evaporated so that saturated soil got completely dry and sieved in a 2 mm sieve to obtain the air dried fine soil (ADFS). The volumes of dried soils were conditioned in three columns to characterize T0, T1, T2, T3, T4 and T5 treatments. The same procedure was carried out for probes calibration. At that moment, four probes were installed by column, totaling 18 columns. The empirical model to estimate the volumetric soil humidity under study showed an adequate degree of determination. At last, It was possible to establish an empirical model that connected AEC recorded by the TDR equipment and electrical conductivity of saturated soil sample (ECss), making possible the use of this technique on soil salinity estimation.