scholarly journals Feasibility of Using the Two-Source Energy Balance Model (TSEB) with Sentinel-2 and Sentinel-3 Images to Analyze the Spatio-Temporal Variability of Vine Water Status in a Vineyard

2020 ◽  
Vol 12 (14) ◽  
pp. 2299 ◽  
Author(s):  
Joaquim Bellvert ◽  
Christian Jofre-Ĉekalović ◽  
Ana Pelechá ◽  
Mercè Mata ◽  
Hector Nieto
Keyword(s):  
Water Stress ◽  
Energy Balance ◽  
Temporal Variability ◽  
Water Status ◽  
The Other ◽  
Balance Model ◽  
Crop Water ◽  
Spatio Temporal ◽  
Crop Water Stress ◽  
Sentinel 2

In viticulture, detailed spatial information about actual evapotranspiration (ETa) and vine water status within a vineyard may be of particular utility when applying site-specific, precision irrigation management. Over recent decades, extensive research has been carried out in the use of remote sensing energy balance models to estimate and monitor ETa at the field level. However, one of the major limitations remains the coarse spatial resolution in the thermal infrared (TIR) domain. In this context, the recent advent of the Sentinel missions of the European Space Agency (ESA) has greatly improved the possibility of monitoring crop parameters and estimating ETa at higher temporal and spatial resolutions. In order to bridge the gap between the coarse-resolution Sentinel-3 thermal and the fine-resolution Sentinel-2 shortwave data, sharpening techniques have been used to downscale the Sentinel-3 land surface temperature (LST) from 1 km to 20 m. However, the accurate estimates of high-resolution LST through sharpening techniques are still unclear, particularly when intended to be used for detecting crop water stress. The goal of this study was to assess the feasibility of the two-source energy balance model (TSEB) using sharpened LST images from Sentinel-2 and Sentinel-3 (TSEB-PTS2+3) to estimate the spatio-temporal variability of actual transpiration (T) and water stress in a vineyard. T and crop water stress index (CWSI) estimates were evaluated against a vine water consumption model and regressed with in situ stem water potential (Ψstem). Two different TSEB approaches, using very high-resolution airborne thermal imagery, were also included in the analysis as benchmarks for TSEB-PTS2+3. One of them uses aggregated TIR data at the vine+inter-row level (TSEB-PTairb), while the other is based on a contextual method that directly, although separately, retrieves soil and canopy temperatures (TSEB-2T). The results obtained demonstrated that when comparing airborne Trad and sharpened S2+3 LST, the latter tend to be underestimated. This complicates the use of TSEB-PTS2+3 to detect crop water stress. TSEB-2T appeared to outperform all the other methods. This was shown by a higher R2 and slightly lower RMSD when compared with modelled T. In addition, regressions between T and CWSI-2T with Ψstem also produced the highest R2.

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>

Crop water stress index derived from multi-year ground and aerial thermal images as an indicator of potato water status

2014 ◽  
Vol 15 (3) ◽  
pp. 273-289 ◽  
Author(s):  
Ronit Rud ◽  
Y. Cohen ◽  
V. Alchanatis ◽  
A. Levi ◽  
R. Brikman ◽  
...  
Keyword(s):  
Water Stress ◽  
Water Status ◽  
Stress Index ◽  
Crop Water ◽  
Crop Water Stress Index ◽  
Thermal Images ◽  
Water Stress Index ◽  
Crop Water Stress

scholarly journals Determination of Crop Water Stress Index by Infrared Thermometry in Grapefruit Trees Irrigated with Saline Reclaimed Water Combined with Deficit Irrigation

2019 ◽  
Vol 11 (7) ◽  
pp. 757 ◽  
Author(s):  
Cristina Romero-Trigueros ◽  
José María Bayona Gambín ◽  
Pedro Antonio Nortes Tortosa ◽  
Juan José Alarcón Cabañero ◽  
Emilio Nicolás Nicolás
Keyword(s):  
Water Stress ◽  
Water Status ◽  
Reclaimed Water ◽  
Stress Index ◽  
Crop Water ◽  
Crop Water Stress Index ◽  
Infrared Thermometry ◽  
Water Stress Index ◽  
Thermal Indicators ◽  
Crop Water Stress

Water is not always accessible for agriculture due to its scarcity. In order to successfully develop irrigation strategies that optimize water productivity characterization of the plant, the water status is necessary. We assessed the suitability of thermal indicators by infrared thermometry (IRT) to determine the water status of grapefruit in a commercial orchard with long term irrigation using saline reclaimed water (RW) and regulated deficit irrigation (RDI) in Southeastern Spain. The results showed that Tc-Ta differences were positive in a wide range of vapor pressure deficits (VPD), and the major Tc-Ta were found at 10.00 GMT, before and after the highest daily values of VPD and solar radiation, respectively, were reached. In addition, we evaluated the relationships between Tc-Ta and VPD to establish the Non-Water Stressed Baselines (NWSBs), which are necessary to accurately calculate the crop water stress index (CWSI). Two important findings were found, which include i) the best significant correlations (p < 0.005) found at 10.00 GMT and their slopes were positive, and ii) NWSBs showed a marked hourly and seasonal variation. The hourly shift was mainly explained by the variation in solar radiation since both the NWSB-slope and the NWSB-intercept were significantly correlated with a zenith solar angle (θZ) (p < 0.005). The intercept was greater when θZ was close to 0 (at midday) and the slope displayed a marked hysteresis throughout the day, increasing in the morning and decreasing in the afternoon. The NWSBs determination, according to the season improved most of their correlation coefficients. In addition, the relationship significance of Tc-Ta versus VPD was higher in the period where the intercept and Tc-Ta were low. CWSI was the thermal indicator that showed the highest level of agreement with the stem water potential of the different treatments even though Tc and Tc-Ta were also significantly correlated. We highlight the suitability of thermal indicators measured by IRT to determine the water status of grapefruits under saline (RW) and water stress (RDI) conditions.

Using a crop water stress index based on a sap flow method to estimate water status in conilon coffee plants

2020 ◽  
Vol 241 ◽  
pp. 106343
Author(s):  
Afonso Zucolotto Venturin ◽  
Claudinei Martins Guimarães ◽  
Elias Fernandes de Sousa ◽  
José Altino Machado Filho ◽  
Weverton Pereira Rodrigues ◽  
...  
Keyword(s):  
Water Stress ◽  
Sap Flow ◽  
Water Status ◽  
Stress Index ◽  
Crop Water ◽  
Crop Water Stress Index ◽  
Flow Method ◽  
Water Stress Index ◽  
Coffee Plants ◽  
Crop Water Stress

scholarly journals Estimation of Reference Evapotranspiration using Cropwat for Kadam Watershed

2020 ◽  
Vol 9 (4) ◽  
pp. 338-341
Keyword(s):  
Water Stress ◽  
Reference Evapotranspiration ◽  
Hydrologic Cycle ◽  
Balance Model ◽  
Component Part ◽  
Crop Water ◽  
Gis Environment ◽  
Main Component ◽  
Crop Water Stress

Due to the overuse of available water resources, it has become very important to define appropriate strategies for planning and management of watershed. The objective for the study is determination of reference evapotranspiration using CROPWAT 8.0 software in GIS environment, which includes a simple water balance model and one of the main component part of the hydrologic cycle, which allows the simulation of crop water stress conditions and estimation of yield reductions based on well-established methodologies. This paper focused on the estimation of reference evapotranspiration using Cowpat 8.0 .

scholarly journals Evaluation of the Crop Water Stress Index as an Indicator for the Diagnosis of Grapevine Water Deficiency in Greenhouses

Horticulturae ◽  
2020 ◽  
Vol 6 (4) ◽  
pp. 86
Author(s):  
Chen Ru ◽  
Xiaotao Hu ◽  
Wene Wang ◽  
Hui Ran ◽  
Tianyuan Song ◽  
...  
Keyword(s):  
Water Stress ◽  
Water Status ◽  
Leaf Temperature ◽  
Stress Index ◽  
Plant Water ◽  
Crop Water ◽  
Crop Water Stress Index ◽  
Water Stress Index ◽  
The Relationship ◽  
Crop Water Stress

Precise irrigation management of grapevines in greenhouses requires a reliable method to easily quantify and monitor the grapevine water status to enable effective manipulation of the water stress of the plants. This study evaluated the applicability of crop water stress index (CWSI) based on the leaf temperature for diagnosing the grapevine water status. The experiment was conducted at Yuhe Farm (northwest China), with drip-irrigated grapevines under three irrigation treatments. Meteorological factors, soil moisture contents, leaf temperature, growth indicators including canopy coverage and fruit diameter, and physiological indicators including SPAD (relative chlorophyll content), stem water potential (φs), stomatal conductance (gs), and transpiration rate (E) were studied during the growing season. The results show that the relationship between the leaf-air temperature difference (Tc-Ta) and the plant water status indicators (φs, gs, E) were significant (P < 0.05), and the relationship between gs, E and Tc-Ta was the closest, with R2 values ranging from 0.530–0.604 and from 0.545–0.623, respectively. CWSI values are more easily observed on sunny days, and it was determined that 14:00 BJS is the best observation time for the CWSI value under different non-water-stressed baselines. There is a reliable linear correlation between the CWSI value and the soil moisture at 0–40 cm (P < 0.05), which could provide a reference when using the CWSI to diagnose the water status of plants. Compared with the Tc-Ta value, the CWSI could more accurately monitor the plant water status, and above the considered indictors, gs has the greatest correlation with the CWSI.

scholarly journals Application of a Daily Crop Water Stress Index to Deficit Irrigate Malbec Grapevine under Semi-Arid Conditions

Agriculture ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 492
Author(s):  
Krista C. Shellie ◽  
Bradley A. King
Keyword(s):  
Water Stress ◽  
Water Status ◽  
Irrigation Scheduling ◽  
Stress Index ◽  
Crop Water ◽  
Crop Water Stress Index ◽  
Irrigation Amount ◽  
Water Stress Index ◽  
Arid Conditions ◽  
Crop Water Stress

Precision irrigation of wine grape is hindered by the lack of an automated method for monitoring vine water status. The objectives of this study were to: Validate an automated model for remote calculation of a daily crop water stress index (CWSI) for the wine grape (Vitis vinifera L.) cultivar Malbec and evaluate its suitability for use in irrigation scheduling. Vines were supplied weekly with different percentages of evapotranspiration-based estimated water demand (ETc) over four growing seasons. In the fifth growing season, different daily CWSI threshold values were used to trigger an irrigation event that supplied 28 mm of water. All three indicators of vine water status (CWSI, midday leaf water potential (Ψlmd), and juice carbon isotope ratio (δ13C)) detected an increase in stress severity as the irrigation amount decreased. When the irrigation amount decreased from 100% to 50% ETc, 70% to 35% ETc, or the daily CWSI threshold value increased from 0.4 to 0.6, berry fresh weight and juice titratable acidity decreased, juice δ13C increased, the weekly CWSI increased, and Ψlmd decreased. Under the semi-arid conditions of this study, utilizing a daily CWSI threshold for irrigation scheduling reduced the irrigation amount without compromising the yield or changes in berry composition and remotely provided automated decision support for managing water stress severity in grapevine.

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