DETERMINAÇÃO DO ÍNDICE DE ESTRESSE HÍDRICO EM TOMATEIROS CEREJA ( Lycopersicum Solanum var. cerasiforme.) COM CÂMARA INFRAVERMELHA

Abstract

Infrared thermometry is a possibility of detection of plant water stress by measuring the temperature of a portion of the canopy without requiring physical contact with the sheets. The purpose of this study was determining the crop water stress index in tomato cherry using the leaf temperature in plants as an indicator of water stress. Plants were grown in a greenhouse situated in the Department of Biosystems Engineering at the Escola Superior de Agricultura "Luiz de Queiroz "in Piracicaba, São Paulo. The plants were conducted in eight 500L boxes. The soil of the boxes is Oxisol eutrophic typical. Previously, were defined two groups: with induced water stress (T0; 24 plants) and without water stress (T1; 24 plants). The temperature of canopy was measured before irrigation using a thermal camera which captures infrared images. The leaf and air temperatures were used to calculation of crop water stress index (IEHC) in two moments: 41 and 47 days after transplanting (DAT) using the lower basal limit (LBI) and a theoretical method. The leaf temperature in group T0 was higher than observed in group T1. We found that: i) highest IEHC in both groups was less than 0.7; ii) IEHC based on theoretical method or LBI, showed that stressed plants have higher IEHC than plants with less water stress. The results indicate that water stress in tomato cherry could be estimated by IEHC based on LBI.

Tomato water stress index as a function of irrigation depths

“…This result corroborates with those found by López et al (2009b) with husk tomato in Mexico, Ghaemi et al (2015) with eggplant in Iran, Ramírez et al (2015) with cherry tomato in Piracicaba-SP, and also those found by Erdem et where: r a -aerodynamic resistance, s m -1 ; γ -psychrometric constant, kPa ºC -1 ; R n -net radiation balance, W m -2 ; G -heat flux in the soil = zero; ρ ar -air density at constant pressure, kg m -3 ; Cp -air specific heat at constant pressure, J kg -1 ºC -1 = 1013; ∆ -slope of the saturation water vapor pressure curve at the temperature, kPa ºC -1 ; and, VPD -vapor pressure deficit, kPa.…”

“…Fast and accurate assessment of plant water status is very useful in irrigation management, especially in crops such as industrial tomato (Solanum lycopersicom L.), which is highly sensitive to water stress (Ramírez et al, 2015).…”

“…It determines the actual transpiration base line of a crop through the difference between canopy and air temperatures, vapor pressure deficit, characteristics of the crop and atmospheric conditions, which allows to quantify the water stress levels in the leaves (López et al, 2009a, b;Sezen et al, 2014;Ramírez et al, 2015).…”

Padrões de resposta termal ao déficit hídrico na cultura do café irrigado por gotejamento

“…O parâmetro Crop Water Stress Index (CWSI), determinado através da temperatura foliar, pode ser uma alternativa para obtenção do estado hídrico das plantas e este tem sido estudado em diversas culturas como cana-de-açúcar (TRENTIN, 2010), citrus (ZARCO-TEJADA; GONZÁLEZ-DUGO; BERNI, 2012), uva (BELLVERT et al, 2014), oliveira (BERNI et al, 2009), algodão (COHEN et al, 2014, tomate (RAMÍREZ et al, 2015a) …”

“…A partir desses valores é possível afirmar que nas condições do experimento, a temperatura foliar, medida com a câmera térmica, das plantas submetidas a lâminas deficitárias foi aproximadamente 1,0 ºC maior que a temperatura foliar das plantas que receberam os tratamentos L130% e L100%. Ramírez et al (2015a) …”