Obtenção de propriedades físico-hídricas do solo: modelagem, posição e frequência de uso de sensores eletrônicos

Abstract

Proper irrigation management, agro-hydrological simulations and soil water balance depend on how the soil water content is obtained. The types of sensors, the location, the quantity to be installed and the frequency of obtaining the water content in the soil are examples of doubts that still persist in carrying out irrigation management and the soil water balance. Therefore, the thesis here focuses on contributing to the resolution of these problems and aims to verify whether different procedures for obtaining soil hydraulic properties, the positioning and quantity of soil water sensors affect irrigation management, modeling agro-hydrologic and soil water balance estimates in drip-irrigated cultivation. The experiment was conducted in a greenhouse on the premises of the Water and Soil Engineering Center, at the Federal University of Recôncavo da Bahia in Cruz das Almas-Ba, located in the geographic coordinates (Latitude: 12° 39' 11'' South, Longitude: 39° 7' 19'' West). The interior of the greenhouse had 36 fiberglass boxes with an area of 1.21 m2 (0.9 m deep; 1.1 m wide and 1.1 m long) that were used for cultivation, with 1 lysimeter equipped with 32 TDR sensors and a weighing platform. To determine the hydraulic parameters of the soil by inverse modeling, an evaporation test was set up based on the hydraulic transients. Soil water content was monitored in two ways: (i) using TDR sensors (ii) GS1 capacitive sensors. For each way of monitoring soil moisture, the sensors were distributed at depths of 0.05, 0.15, 0.25, 0.35 and 0.45 m. In determining the soil water balance, the sensors should preferably be installed in the wet bulb zone close to the dripper. The study reveals that when sensors can be distributed in 2D/3D, the irrigation system or section can be triggered using a single sensor signal that represents the average extraction of the entire monitored profile. The type of sensor and the frequency of data collection of soil water content interfered in the results of soil hydraulic properties obtained by inverse modeling with implications for agro-hydrological modeling and irrigation management via soil water sensing.