Normalizing the stress-degree-day parameter for environmental variability

Idso, Sherwood B.; Jackson, R. D.; Pinter, P. J.; Reginato, R. J.; Hatfield, Jerry L.

doi:10.1016/0002-1571(81)90032-7

Cited by 1,115 publications

(747 citation statements)

References 15 publications

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“…1: CWSI E (empirical method) was calculated using Eq. 1, by substituting the lower base line of temperature (T c -T a ) LBL by the lowest difference between crop canopy temperature (T c ) and mean air temperature (T a ), and the upper base line of temperature (T c -T a ) UBL by the maximum differences between T c and T a , as proposed by Idso et al (1981). It makes this methodology easier to use, compared with the theoretical method, which has more complex calculations.…”

Section: Methodsmentioning

confidence: 99%

Tomato water stress index as a function of irrigation depths

Silva

Freitas

et al. 2018

Rev. bras. eng. agríc. ambient.

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A B S T R A C TInfrared thermometry allows evaluating plants under water stress, by measuring the canopy temperature, without the need of physical contact with the leaves. The aim of this study was to determine the water stress index of the tomato crop for industrial processing (Hybrid 'BRS Sena'), as a function of irrigation depths applied by subsurface drip irrigation, in Southern Goiás, Brazil, in 2015 and 2016. The experiment was conducted in a randomized block design, with four replicates. The treatments consisted in five irrigation depths: 50, 75, 100, 125 and 150% of crop evapotranspiration. The water stress index of the tomato crop was evaluated using two methodologies, as a function of the canopy temperature, air temperature and other local meteorological parameters, as well as the relationship between water stress index and crop yield. Theoretical and empirical methods estimate CWSI similarly in tomato. In the hottest hours of the day, even under adequate soil moisture conditions, the 'BRS Sena' tomato showed CWSI above 0.2. CWSI is a good indicator to evaluate the water status of the tomato crop for industrial processing and to recommend the moment of irrigation. The higher the CWSI, the lower the yield of 'BRS Sena' tomato.Índice de estresse hídrico de tomateiro em função de lâminas de irrigação R E S U M OA termometria infravermelha permite avaliar o estresse hídrico das plantas através da medição da temperatura do dossel, sem necessidade de contato físico com as folhas. Objetivou-se neste trabalho determinar o índice de estresse hídrico do tomateiro industrial (híbrido BRS Sena) em função de lâminas de irrigação aplicadas por gotejamento subsuperficial, na região Sul de Goiás, nos anos 2015 e 2016. O delineamento experimental foi em blocos ao acaso, com quatro repetições. Os tratamentos consistiram de cinco lâminas de irrigação, iguais a 50, 75, 100, 125 e 150% da evapotranspiração da cultura. Avaliou-se o índice de estresse hídrico do tomateiro por meio de duas metodologias, em função da temperatura no dossel, temperatura do ar e demais parâmetros meteorológicos locais, e também a relação dos valores do índice de estresse hídrico com a produtividade da cultura. Os métodos teórico e empírico estimam de maneira semelhante o CWSI no tomateiro. Nas horas mais quentes do dia, mesmo em condições de umidade adequada no solo, o tomateiro BRS Sena apresentou CWSI acima de 0,2. O CWSI é um bom indicativo para avaliar o estado hídrico do tomateiro industrial e indicar o momento de realizar a irrigação. Quanto maior o CWSI, menor foi a produtividade do tomateiro BRS Sena.

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Section: Methodsmentioning

confidence: 99%

Tomato water stress index as a function of irrigation depths

Silva

Freitas

et al. 2018

Rev. bras. eng. agríc. ambient.

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“…The relationship between vegetation temperature and transpiration rates is affected by water stress experienced by the plants but also by environmental parameters, as the vapor pressure deficit of the air (VPD). The crop water stress index (CWSI) [7] has been proposed to normalize the difference between canopy temperature and air temperature (ΔT) by the evaporative demand. The CWSI can be computed based on an empirical approach relating ΔT to the VPD of a "non-water-stressed baseline" referring to a well-watered crop transpiring at the potential rate (for a recent review refer to [8]).…”

Section: Introductionmentioning

confidence: 99%

Discriminating Irrigated and Rainfed Maize with Diurnal Fluorescence and Canopy Temperature Airborne Maps

Rossini

Panigada

Cilia

et al. 2015

IJGI

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This study evaluates the potential of airborne remote sensing images to detect water stress in maize. Visible and near infrared CASI (Itres Research Ltd., Calgary, AL, Canada) and thermal AHS-160 (Sensytech Inc., Beverly, MA, USA) data were acquired at three different times during the day on a maize field (Zea mays L.) grown with three different irrigation treatments. An intensive field campaign was also conducted concurrently with image acquisition to measure leaf ecophysiological parameters and the leaf area index. The analysis of the field data showed that maize plants were experiencing moderate to severe water stress in rainfed plots and a weaker stress condition in the plots with a water deficit imposed between stem elongation and flowering. Vegetation indices including the normalized difference vegetation index (NDVI) and the photochemical reflectance index (PRI) computed from the CASI images, sun-induced chlorophyll fluorescence (F760) and canopy temperature (Tc) showed different performances in describing the water stress during the day. During the OPEN ACCESS ISPRS Int. J. Geo-Inf. 2015, 4 627 morning overpass, NDVI was the index with the highest discriminant power due to the sensitivity of NDVI to maize canopy structure, affected by the water irrigation treatment. As the day progressed, processes related to heat dissipation through plant transpiration became more and more important and at midday Tc showed the best performances. Furthermore, Tc retrieved from the midday image was the only index able to distinguish all the three classes of water status. Finally, during the afternoon, PRI and F760 showed the best performances. These results demonstrate the feasibility to detect water stress using thermal and optical airborne data, pointing out the importance of careful planning of the airborne surveys as a function of the specific aims of the study.

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“…On these days, certain values were close to zero in the early morning or late afternoon when the PPFD and VPD values were relatively low. Thus, the LT -T values close to zero were not a consequence of stress but likely a response to the low energy available for heating the leaves and increasing atmospheric water demand, as demonstrated by the low VPD values (approximately 0.5 kPa) (Idso et al 1981a;1981b).…”

Section: Resultsmentioning

confidence: 98%

“…6) (Idso et al 1981a), which is a "lower baseline" for a non-stressed crop. The equation for this baseline is similar to a watermelon (Orta et al 2003), wheat (Gontia and Tiwari 2008) and maize (Cárcoma et al 1998).…”

Section: Lt -T Irt -T (°C) Lt -T Irt -Tmentioning

confidence: 99%