scholarly journals Behaviour of relative evapotranspiration with agrometeorological stress indices in wheat

MAUSAM ◽  
2022 ◽  
Vol 46 (1) ◽  
pp. 57-62
Author(s):  
O.P. BISHNOI ◽  
MOHAN SINGH ◽  
SURINDER SINGH
Keyword(s):  
Growth And Development ◽  
Canopy Temperature ◽  
Moisture Stress ◽  
Stomatal Resistance ◽  
Leaf Temperature ◽  
Stress Index ◽  
Complex Behaviour ◽  
Stress Indices ◽  
Stress Effects ◽  
Scheduling Irrigation

Complex behaviour of stress indices with relative evapotranspiration was observed in early and late sown wheat, however, under normal sown conditions it was linearly decreasing. Predawn leaf water potential and transpiration rate proved to be a stable stress index parameter for characterizing the internal moisture status in the plant as compared to the canopy temperature and stomatal resistance under stress conditions in wheat. Since it is easy to quantify canopy/leaf temperature and within seasonal variations it is widely used for scheduling irrigation and quantigying moisture stress effects on growth and development in wheat.  

scholarly journals Water stress indices for the sugarcane crop on different irrigated surfaces

2016 ◽  
Vol 20 (10) ◽  
pp. 925-929 ◽  
Author(s):  
Rodrigo G. Brunini ◽  
José E. P. Turco
Keyword(s):  
Water Stress ◽  
Raw Materials ◽  
Irrigation System ◽  
Canopy Temperature ◽  
Ambient Air ◽  
Saccharum Officinarum ◽  
Stress Index ◽  
Stress Indices ◽  
Sugarcane Crop ◽  
Water Stress Index

ABSTRACT Sugarcane (Saccharum officinarum L.) is a crop of vital importance to Brazil, in the production of sugar and ethanol, power generation and raw materials for various purposes. Strategic information such as topography and canopy temperature can provide management technologies accessible to farmers. The objective of this study was to determine water stress indices for sugarcane in irrigated areas, with different exposures and slopes. The daily water stress index of the plants and the water potential in the soil were evaluated and the production system was analyzed. The experiment was carried out in an “Experimental Watershed”, using six surfaces, two horizontal and the other ones with 20 and 40% North and South exposure slopes. Water stress level was determined by measuring the temperatures of the vegetation cover and the ambient air. Watering was carried out using a drip irrigation system. The results showed that water stress index of sugarcane varies according to exposure and slope of the terrain, while areas whose water stress index was above 5.0 oC had lower yield values.

Assessing canopy temperature-based water stress indices for soybeans under subhumid conditions

2020 ◽  
Author(s):  
Angela Morales Santos ◽  
Reinhard Nolz
Keyword(s):  
Water Stress ◽  
Soil Water ◽  
Water Status ◽  
Canopy Temperature ◽  
Irrigation Scheduling ◽  
Stress Index ◽  
Crop Water ◽  
Stress Indices ◽  
Soil Water Status ◽  
Crop Water Stress

<p>Sustainable irrigation water management is expected to accurately meet crop water requirements in order to avoid stress and, consequently, yield reduction, and at the same time avoid losses of water and nutrients due to deep percolation and leaching. Sensors to monitor soil water status and plant water status (in terms of canopy temperature) can help planning irrigation with respect to time and amounts accordingly. The presented study aimed at quantifying and comparing crop water stress of soybeans irrigated by means of different irrigation systems under subhumid conditions.</p><p>The study site was located in Obersiebenbrunn, Lower Austria, about 30 km east of Vienna. The region is characterized by a mean temperature of 10.5°C with increasing trend due to climate change and mean annual precipitation of 550 mm. The investigations covered the vegetation period of soybean in 2018, from planting in April to harvest in September. Measurement data included precipitation, air temperature, relative humidity and wind velocity. The experimental field of 120x120 m<sup>2</sup> has been divided into four sub-areas: a plot of 14x120 m<sup>2</sup> with drip irrigation (DI), 14x120 m<sup>2</sup> without irrigation (NI), 36x120 m<sup>2</sup> with sprinkler irrigation (SI), and 56x120 m<sup>2</sup> irrigated with a hose reel boom with nozzles (BI). A total of 128, 187 and 114 mm of water were applied in three irrigation events in the plots DI, SI and BI, respectively. Soil water content was monitored in 10 cm depth (HydraProbe, Stevens Water) and matric potential was monitored in 20, 40 and 60 cm depth (Watermark, Irrometer). Canopy temperature was measured every 15 minutes using infrared thermometers (IRT; SI-411, Apogee Instruments). The IRTs were installed with an inclination of 45° at 1.8 m height above ground. Canopy temperature-based water stress indices for irrigation scheduling have been successfully applied in arid environments, but their use is limited in humid areas due to low vapor pressure deficit (VPD). To quantify stress in our study, the Crop Water Stress Index (CWSI) was calculated for each plot and compared to the index resulting from the Degrees Above Canopy Threshold (DACT) method. Unlike the CWSI, the DACT method does not consider VPD to provide a stress index nor requires clear sky conditions. The purpose of the comparison was to revise an alternative method to the CWSI that can be applied in a humid environment.</p><p>CWSI behaved similar for the four sub-areas. As expected, CWSI ≥ 1 during dry periods (representing severe stress) and it decreased considerably after precipitation or irrigation (representing no stress). The plot with overall lower stress was BI, producing the highest yield of the four plots. Results show that DACT may be a more suitable index since all it requires is canopy temperature values and has strong relationship with soil water measurements. Nevertheless, attention must be paid when defining canopy temperature thresholds. Further investigations include the development and test of a decision support system for irrigation scheduling combining both, plant-based and soil water status indicators for water use efficiency analysis.</p>

An infrared-based coefficient to screen plant environmental stress: concept, test and applications

2009 ◽  
Vol 36 (11) ◽  
pp. 990 ◽  
Author(s):  
Guo Yu Qiu ◽  
Kenji Omasa ◽  
Sadanori Sase
Keyword(s):  
Heat Stress ◽  
Water Stress ◽  
Environmental Stress ◽  
Air Temperature ◽  
Canopy Temperature ◽  
Water Shortage ◽  
Leaf Temperature ◽  
Stress Index ◽  
Crop Water Stress Index ◽  
Water Stress Index

By introducing a reference dry leaf (a leaf without transpiration), a formerly proposed plant transpiration transfer coefficient (hat) was applied to detect environmental stress caused by water shortage and high temperature on melon, tomato and lettuce plants under various conditions. Results showed that there were obvious differences between leaf temperature, dry reference leaf temperature and air temperature. The proposed coefficient hat could integrate the three temperatures and quantitatively evaluate the environmental stress of plants. Experimental results showed that the water stress of melon plants under two irrigation treatments was clearly distinguished by using the coefficient. The water stress of a tomato plant as the soil dried under a controlled environmental condition was sensitively detected by using hat. A linear relationship between hat and conventional crop water stress index was revealed with a regression determination coefficient R2 = 0.97. Further, hat was used to detect the heat stress of lettuce plants under high air temperature conditions (28.7°C) with three root temperature treatments (21.5, 25.9 and 29.5°C). The canopy temperature under these treatments was respectively 26.44, 27.15 and 27.46°C and the corresponding hat value was –1.11, –0.74 and –0.59. Heat stress was also sensitively detected using hat. The main advantage of hat is its simplicity for use in infrared applications.

TEMPERATURE AND STOMATAL RESISTANCE OF SOYBEAN LEAVES

1979 ◽  
Vol 59 (1) ◽  
pp. 153-162 ◽  
Author(s):  
C. R. SUMAYAO ◽  
E. T. KANEMASU
Keyword(s):  
Water Content ◽  
Soil Water ◽  
Soil Water Content ◽  
Air Temperature ◽  
Canopy Temperature ◽  
Temperature Inversion ◽  
Stomatal Resistance ◽  
Leaf Temperature ◽  
First Case ◽  
Soybean Leaves

A field study was conducted during the 1977 growing season to determine the effect of soil-water content on the air temperature within and above the soybean canopy and consequently on the leaf temperature and stomatal resistance of soybeans (Glycine max L. ’Calland’). Leaf temperature at two heights and air temperature at five heights within and above the canopy were measured with copper-constantan thermocouples while stomatal resistances were measured with an automatic porometer. At soil-water depletions <65%, a daytime air-temperature inversion occurred within and above the canopy, while at depletions >65% air temperature decreased with height. In the first case the canopy temperature was cooler than the air above the canopy when air temperature exceeded 32 °C and the lower canopy leaves were cooler than the upper canopy leaves when they were completely shaded by the upper leaves. At soil-water depletions greater than 65% the canopy was warmer than the air and the lower canopy leaves were warmer than the upper canopy leaves. Stomatal resistance, on the other hand, decreased with height within the canopy irrespective of soil-water content.

A Theoretical Model Research of Rice Water Stress Index Based on Automated Infrared Thermal Imaging

2013 ◽  
Vol 712-715 ◽  
pp. 433-438 ◽  
Author(s):  
Ming Chao Cao ◽  
Wen Zhong Zhang ◽  
Ya Dong Han ◽  
Chen Yao ◽  
Yi Tao Wang ◽  
...  
Keyword(s):  
Water Stress ◽  
Theoretical Model ◽  
Infrared Imaging ◽  
Water Status ◽  
Canopy Temperature ◽  
Stomatal Resistance ◽  
Stress Index ◽  
Infrared Thermal Imaging ◽  
Water Stress Index ◽  
Rice Water

It detected the canopy temperature of rice via automated infrared imaging technology in the test under different irrigation condition, and used theCWSItheoretical model to diagnose whether the crop suffered water stress or not. It also analyzed the water stress index theoretical model of crop and other indexes on reflecting the water status of crop, including the relationship between theCWSIand leaf stomatal resistance, theCWSIand leaf net photosynthetic rate, and theCWSIand the soil moisture content. The results showed that the relations between the surface theoretical model and the above indexes were fine. It meant theCWSIwell reflected the features of water stress of rice.

A MOISTURE STRESS INDEX FOR WHEAT BY MEANS OF A MODULATED SOIL MOISTURE BUDGET

1968 ◽  
Vol 48 (5) ◽  
pp. 535-544 ◽  
Author(s):  
A. R. Mack ◽  
W. S. Ferguson
Keyword(s):  
Soil Moisture ◽  
Stress Function ◽  
Potential Evapotranspiration ◽  
Moisture Stress ◽  
Moisture Distribution ◽  
Stress Index ◽  
Wheat Crop ◽  
Moisture Budget ◽  
Dough Stage ◽  
Soil Moisture Budget

Actual evapotranspiration (AE), soil moisture distribution, and moisture stress for a wheat crop (PE-AE) were estimated by the modulated soil moisture budget of Holmes and Robertson. The estimated soil moisture was reasonably well correlated with soil moisture measured weekly by means of gypsum blocks. Wheat yields from experimental plots in the corresponding area were related more closely to the moisture stress function (PE-AE: r = − 0.83), than to the seasonal precipitation (r = 0.62), the potential evapotranspiration (PE) or the evapotranspiration ratio (AE/PE). Regression analyses showed that the grain yields were reduced by an average of 156 (±sb = 40) kg/ha per cm of moisture stress from emergence to harvest, or by 311 and 69 kg/ha per cm of stress, from the fifth-leaf to the soft-dough stage and from the soft-dough stage to maturity, respectively. The moisture stress function may be used to characterize the soil–plant–atmosphere environment for the growing season of a crop. Precipitation and evapotranspiration data are presented annually for three standardized growing periods at Brandon from 1921 to 1963.

scholarly journals Correlation Analysis Procedures for Canopy Spectral Reflectance Data of Seashore Paspalum under Traffic Stress

2003 ◽  
Vol 128 (3) ◽  
pp. 343-348 ◽  
Author(s):  
Yiwei Jiang ◽  
Robert N. Carrow ◽  
Ronny R. Duncan
Keyword(s):  
Spectral Reflectance ◽  
Soil Compaction ◽  
Canopy Temperature ◽  
Quality Analysis ◽  
Stress Index ◽  
Canopy Reflectance ◽  
Seashore Paspalum ◽  
First Derivative ◽  
Turf Quality ◽  
Optimum Position

Traffic stresses often cause a decline in turfgrass quality. Analysis of spectral reflectance is valuable for assessing turfgrass canopy status. The objectives of this study were to determine correlations of narrow band canopy reflectance and selected reflectance indices with canopy temperature and turf quality for seashore paspalum exposed to wear and wear plus soil compaction traffic stresses, and to evaluate the effects of the first derivative of reflectance and degree of data smoothing (spectral manipulations) on such correlations. `Sea Isle 1' seashore paspalum (Paspalum vaginatum Swartz) was established on a simulated sports field during 1999 and used for this study. Compared to original reflectance, the first derivative of reflectance increased the correlation coefficient (r) of certain wavelengths with canopy temperature and turf quality under both traffic stresses. Among 217 wavelengths tested between 400 and 1100 nm, the peak correlations of the first derivative of reflectance occurred at 661 nm and 664 nm for both canopy temperature and turf quality under wear stress, respectively, while the highest correlations were found at 667 nm and 820 to 869 nm for both variables under wear plus soil compaction. Collectively, the first derivative of reflectance at 667 nm was the optimum position to determine correlation with canopy temperature (r > 0.62) and turf quality (r < -0.72) under both traffic stresses. All correlations were not sensitive to degrees of smoothing of reflectance from 400 to 1100 nm. A ratio of R936/R661 (IR/R, Infrared/red) and R693/759 (stress index) had the strongest correlations with canopy temperature for wear (r = -0.63) and wear plus soil compaction (r = 0.66), respectively; and a ratio of R693/R759 had the strongest correlation with turf quality for both wear (r = -0.89) and wear plus soil compaction (r = -0.82). The results suggested that the first derivative of reflectance could be used to estimate any single wavelength simultaneously correlated with multiple turf canopy variables such as turf quality and canopy temperature, and that the stress index (R693/R759) was also a good indicator of canopy stress status.

scholarly journals Monitoring canopy and air temperature of dominant vegetation in tropical semi-arid using bioclimatic model

2016 ◽  
Vol 1 (1) ◽  
pp. 1-12
Author(s):  
Josiclêda Domiciano Galvíncio ◽  
Rejane Magalhães de Mendonça Pimentel
Keyword(s):  
Climate Change ◽  
Air Temperature ◽  
Dominant Species ◽  
Canopy Temperature ◽  
Leaf Temperature ◽  
Climate Change Scenarios ◽  
Arid Environments ◽  
Intergovernmental Panel ◽  
Dry Land ◽  
Bioclimatic Model

Typical vegetation of arid environments consists of few dominant species highly threatened by climate change. Jurema preta (Mimosa tenuiflora (Willd.) Poiret) is one of these successful species that now is dominant in extensive semiarid areas in the world. The development of a simple bioclimatic model using climate change scenarios based on optimistic and pessimistic predictions of the Intergovernmental Panel on Climate Change (IPCC) shown as a simple tool to predict possible responses of dominant species under dry land conditions and low functional biodiversity. The simple bioclimatic model proved satisfactory in creating climate change scenarios and impacts on the canopy temperature of Jurema preta in semiarid Brazil. The bioclimatic model was efficient to obtain spatially relevant estimations of air temperature from determinations of the surface temperature using satellite images. The model determined that the average difference of 5oC between the air temperature and the leaf temperature for Jurema preta, and an increase of 3oC in air temperature, promote an increase of 2oC in leaf temperature. It leads to disturbances in vital physiological mechanisms in the leaf, mainly the photosynthesis and efficient use of water.

On-the-go thermal imaging for water status assessment in commercial vineyards

2017 ◽  
Vol 8 (2) ◽  
pp. 520-524
Author(s):  
S. Gutiérrez ◽  
M. P. Diago ◽  
J. Fernández-Novales ◽  
J. Tardaguila
Keyword(s):  
Thermal Imaging ◽  
Water Status ◽  
Canopy Temperature ◽  
Stress Index ◽  
Coefficient Of Determination ◽  
Stem Water Potential ◽  
Water Stress Index ◽  
Status Assessment ◽  
Commercial Vineyard ◽  
East And West

The goal of this work was the assessment of commercial vineyard water status using on-the-go thermal imaging. On-the-go thermal imaging acquisition was conducted with a thermal camera operating at 1.20 m distance from the canopy, mounted on a quad moving at 5 km/h. Canopy temperature, cross water stress index (CWSI) and stomatal conductance index (Ig) were strongly and significantly correlated to stem water potential (Ψstem) in east and west side of the canopy. For CWSI, the values of the coefficient of determination (R2) were 0.88*** and 0.73*** for east and west sides, respectively. As regards the index Ig, its relationships with Ψstem showed R2=0.89*** and R2=0.77*** for east and west sides, respectively. These results are promising and evidence the potential of on-the-go thermal imaging to become a new tool to evaluate the vineyard water status.

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