ARE SAP FLOW AND CANOPY TEMPERATURE MEASUREMENTS USEFUL ALTERNATIVES TO STEM WATER POTENTIAL FOR DETECTING PLANT WATER STRESS IN CITRUS TREES?

The sensitivity of leaf (ψleaf) and stem (ψstem) water potential and stomatal conductance (gs) to soil moisture availability in apple (Malus domestics Borkh.) trees and their correlation with yield components were studied in a field experiment. Two drip irrigation treatments, 440 mm (H) and 210 mm (L), were applied to a `Golden Delicious' apple orchard during cell enlargement stage (55-173 days after full bloom). Data collected included ψstem, y leaf, gs, and soil water potential at 25 (ψsoil-25) and 50 cm (ψsoil-50). No differences in midday ψleaf's were found between irrigation treatments. Stem water potential was higher in the H treatment than in the L treatment in diurnal measurements, and at midday throughout the season. Stomatal conductance of the H treatment was higher than the L treatment throughout the day. Stomatal conductance between 0930 and 1530 hr were highly correlated with ψstem. The H treatment increased the percentage of fruit >65 mm, and increased the proportion of earlier harvested fruit reaching marketable size compared to the L treatment. Fruit size in the first harvest and the total yield were highly correlated with ψstem. The degree of correlation between plant water stress indicators and yield component decreased in the following order: ψstem>ψsoil-25,>ψsoil-50>ψleaf. The data suggest that midday ψstem may serve as a preferable plant water stress indicator with respect to fruit size.

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MIDDAY STEM WATER POTENTIAL AS A PLANT WATER STRESS INDICATOR FOR IRRIGATION SCHEDULING IN FRUIT TREES

Acta Horticulturae ◽

10.17660/actahortic.2000.537.52 ◽

2000 ◽

pp. 447-454 ◽

Cited By ~ 44

Author(s):

A. Naor

Keyword(s):

Water Stress ◽

Water Potential ◽

Fruit Trees ◽

Irrigation Scheduling ◽

Plant Water ◽

Stem Water Potential ◽

Plant Water Stress ◽

Stress Indicator ◽

Stem Water

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Microtensiometers Accurately Measure Stem Water Potential in Woody Perennials

Plants ◽

10.3390/plants10122780 ◽

2021 ◽

Vol 10 (12) ◽

pp. 2780

Author(s):

Victor Blanco ◽

Lee Kalcsits

Keyword(s):

Water Potential ◽

Leaf Gas Exchange ◽

Water Status ◽

Full Range ◽

Canopy Temperature ◽

Plant Water ◽

Stem Water Potential ◽

Woody Tissue ◽

Woody Perennials ◽

Stem Water

Stem water potential (Ψstem) is considered to be the standard measure of plant water status. However, it is measured with the pressure chamber (PC), an equipment that can neither provide continuous information nor be automated, limiting its use. Recent developments of microtensiometers (MT; FloraPulse sensors), which can continuously measure water tension in woody tissue of the trunk of the tree, can potentially highlight the dynamic nature of plant water relations. Thus, this study aimed to validate and assess the usefulness of the MT by comparing the Ψstem provided by MT with those same measurements from the PC. Here, two irrigation treatments (a control and a deficit treatment) were applied in a pear (Pyrus communis L.) orchard in Washington State (USA) to capture the full range of water potentials in this environment. Discrete measurements of leaf gas exchange, canopy temperature and Ψstem measured with PC and MT were made every two hours for four days from dawn to sunset. There were strong linear relationships between the Ψstem-MT and Ψstem-PC (R2 > 0.8) and with vapor pressure deficit (R2 > 0.7). However, Ψstem-MT was more variable and lower than Ψstem-PC when Ψstem-MT was below −1.5 MPa, especially during the evening. Minimum Ψstem-MT occurred later in the afternoon compared to Ψstem-PC. Ψstem showed similar sensitivity and coefficients of variation for both PC and MT acquired data. Overall, the promising results achieved indicated the potential for MT to be used to continuously assess tree water status.

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Multispectral reflectance vegetation indices are highly sensitive to water stress in grapefruit trees

10.5194/egusphere-egu2020-11408 ◽

2020 ◽

Author(s):

Pablo Berrios ◽

Abdelmalek Temnani ◽

David Pérez ◽

Ismael Gil ◽

Susana Zapata ◽

...

Keyword(s):

Water Stress ◽

Water Potential ◽

Vegetation Index ◽

Pearson Correlation ◽

Vegetation Indices ◽

Irrigation Scheduling ◽

Plant Water ◽

Citrus Paradisi ◽

Stem Water Potential ◽

Stem Water

The sensitivity to water stress of different plant water indicators (PWI) at different plot scales (leaf and aerial) was evaluated during the second fruit growth stage of grapefruit (Citrus paradisi cv. Star Ruby) trees growing in a commercial orchard for a sustainable irrigation scheduling. Trees were drip-irrigated and submitted to two irrigation treatments: (i) a control (CTL), irrigated at 100% of crop evapotranspiration to avoid any soil water limitations, and (ii) a non-irrigated (NI) treatment, irrigated as the control until the 104 days after full bloom (DAFB) when the irrigation was suppressed, until to reach a severe water stress level in the plants (around -2.3 MPa of stem water potential at solar midday). The plant water indicators studied were: stem water potential (SWP); leaf conductance (Lc); net photosynthesis (Pn), and several vegetation indices (VI) in the visible spectral region derived from an unmanned aerial vehicle equipped with a multispectral sensor. The measurements were made at 9, 12 and 18h (solar time) on 50 and 134 DAFB, coinciding with a fruit diameter of 20 and 70 mm, respectively. The correlation analysis between the PWI at leaf scale (SWP, Lc and Pn) and at aerial scale showed relatively poor results, with Pearson correlation coefficients (r values) around 0.6. However, SWP presented the highest r value with the normalized difference vegetation index (NVDI), green index (GI), normalized difference greenness vegetation index (NDGI) and red green ratio index (RGRI) showing the higher coefficients 0.80, 0,80, 0.85 and 0.86, respectively. In addition, a quadratic regression curve fitting was made for the SWP and aforementioned indices, obtaining values &#8203;&#8203;of R2 around 0.7 in all cases; the best fit corresponded to SWP = - 4.869 + 15.765 NDGI - 14.283 NDGI2 (R2 = 0.749) to predict SWP values between -0.5 and -2.3 MPa. Results obtained show the possibility of using certain vegetation indices to be used in the detection of water stress in adult grapefruits, and thus propose a sustainable and efficient irrigation scheduling.Funding:-WATER4EVER is funded by the European Commission under the framework of the ERA-NET COFUND WATERWORKS 2015 Programme-RIS3MUR REUSAGUA is funded by the Consejer&#237;a de Empresa, Industria y Portavoc&#237;a of the Murcia Region under the Feder Operational Program 2014-2020

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Effect of Fall Irrigation Level in `Mauritius' and `Floridian' Lychee on Soil and Plant Water Status, Flowering Intensity, and Yield

Journal of the American Society for Horticultural Science ◽

10.21273/jashs.123.1.150 ◽

1998 ◽

Vol 123 (1) ◽

pp. 150-155 ◽

Cited By ~ 22

Author(s):

R.A. Stern ◽

M. Meron ◽

A. Naor ◽

R. Wallach ◽

B. Bravdo ◽

...

Keyword(s):

Water Stress ◽

Water Potential ◽

Shoot Growth ◽

Water Status ◽

Plant Water ◽

Stem Water Potential ◽

Irrigation Level ◽

Irrigation Control ◽

Stem Water ◽

Flowering Intensity

The effect of fall irrigation level in `Mauritius' and `Floridian' lychee (Litchi chinensis Sonn.) on soil and plant water status, flowering intensity, and yield the following year was studied in a field during 2 consecutive years. At the end of the second vegetative flush after harvest (1 Oct. 1994 and 10 Oct. 1995), four irrigation treatments were initiated: 0.5, 0.25, 0.125, and 0 Class A pan evaporation coefficients designated 100%, 50%, 25%, and 0%. The three lower irrigation levels effectively stopped shoot growth, suggesting the 50% treatment to be the threshold for shoot growth cessation in both years. For both years, flowering intensity and yield in the 100% treatment were lower than those following the other three treatments. Soil and plant water-stress indicators responded to the water-stress irrigation treatments. However soil water-potential values were highly variable relative to plant water potentials. Stem water potential differed more markedly between treatments than leaf water potential. Midday stem water potential appeared to be the best water-stress indicator for irrigation control. Midday stem water potential in both years was correlated with midday vapor-pressure deficit, suggesting that the threshold for irrigation control should take into account evaporative demand.

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Estimation water status of the vineyard by calculating multispectral index from satellite images

10.5194/egusphere-egu21-2187 ◽

2021 ◽

Author(s):

Marta Rodríguez-Fernández ◽

María Fandiño ◽

Xesús Pablo González ◽

Javier J. Cancela

Keyword(s):

Water Stress ◽

Water Potential ◽

Spectral Index ◽

Satellite Images ◽

Irrigation System ◽

Water Status ◽

Stress Index ◽

Stem Water Potential ◽

Stem Water ◽

Water Potential Measurements

The estimation of the water status in the vineyard, is a very important factor, in which every day the winegrowers show more interest since it directly affects the quality and production in the vineyards. The situation generated by COVID-19 in viticulture, adds importance to tools that provide information of the hydric status of vineyard plants in a telematic way.In the present study, the stem water potential in the 2018 and 2019 seasons, is analysed in a vineyard belonging to the Rias Baixas wine-growing area (Vilagarcia de Arousa, Spain), with 32 sampling points distributed throughout the plot, which allows the contrast and validation with the remote sensing methodology to estimate the water status of the vineyard using satellite images.The satellite images have been downloaded from the Sentinel-2 satellite, on the closets available dates regarding the stem water potential measurements, carried out in the months of June to September, because this dates are considered the months in which vine plants have higher water requirements.With satellite images, two spectral index related to the detection of water stress have been calculated: NDWI (Normalized Difference Water Index) and MSI (Moisture Stress Index). Stem water potential measurements, have allowed a linear regression with both index, to validate the use of these multispectral index to determine water stress in the vineyard.Determination coefficients of r2=0.62 and 0.67, have been obtained in July and August 2018 and 0.54 in June of 2019 for the NDWI index, as well as values of 0.53 and 0.63 in July 2018 and June 2019 respectively, when it has been analysed the MSI index.Between both seasons, the difference observed, that implies slightly greater water stress in 2019, is reflected in the climate conditions during the summer months, with an average accumulated rainfall that doesn&#8217;t exceed 46 mm of water. Although, the NDWI index has allowed to establish better relationships in the 2018 season respect to the MSI index and the 2019 season, (r2=0.60 NDWI in 2018), as well as greater differences in terms of water stress presented in the vineyard.With the spectral index calculated, it has been possible to validate the use of these index for the determination of the water stress of the vineyard plants, as an efficient, fast and less expensive method, which allows the application of an efficient irrigation system in the vineyard.

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Estimation of water stress in olive orchards through remote sensing data analysis

10.5194/egusphere-egu21-9521 ◽

2021 ◽

Author(s):

Luz Karime Atencia ◽

María Gómez del Campo ◽

Gema Camacho ◽

Antonio Hueso ◽

Ana M. Tarquis

Keyword(s):

Remote Sensing ◽

Water Stress ◽

Water Potential ◽

Statistical Tests ◽

Remote Sensing Data ◽

Olive Tree ◽

Fruit Trees ◽

Data Sets ◽

Stem Water Potential ◽

Stem Water

Olive is the main fruit tree in Spain representing 50% of the fruit trees surface, around 2,751,255 ha. Due to its adaptation to arid conditions and the scarcity of water, regulated deficit irrigation (RDI) strategy is normally applied in traditional olive orchards and recently to high density orchards. The application of RDI is one of the most important technique used in the olive hedgerow orchard. An investigation of the detection of water stress in nonhomogeneous olive tree canopies such as orchards using remote sensing imagery is presented.In 2018 and 2019 seasons, data on stem water potential were collected to characterize tree water state in a hedgerow olive orchard cv. Arbequina located in Chozas de Canales (Toledo). Close to the measurement&#8217;s dates, remote sensing images with spectral and thermal sensors were acquired. Several vegetation indexes (VI) using both or one type of sensors were estimated from the areas selected that correspond to the olive crown avoiding the canopy shadows.Nonparametric statistical tests between the VIs and the stem water potential were carried out to reveal the most significant correlation. The results will be discussing in the context of robustness and sensitivity between both data sets at different phenological olive state.ACKNOWLODGEMENTSFinancial support provided by the Spanish Research Agency co-financed with European Union FEDER funds (AEI/FEDER, UE, AGL2016-77282-C3-2R project) and Comunidad de Madrid through calls for grants for the completion of Industrial Doctorates, is greatly appreciated.

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Unexpected relationships between δ13C and wine grape performance in organic farming

OENO One ◽

10.20870/oeno-one.2013.47.4.1556 ◽

2013 ◽

Vol 47 (4) ◽

pp. 269 ◽

Cited By ~ 5

Author(s):

Edoardo Antonio Costantino Costantini ◽

Alessandro Agnelli ◽

Pierluigi Bucelli ◽

Aldo Ciambotti ◽

Valentina Dell’Oro ◽

...

Keyword(s):

Water Stress ◽

Water Potential ◽

Soil Water ◽

Organic Farming ◽

Water Availability ◽

Stress Conditions ◽

Soil Water Availability ◽

Wine Grape ◽

Stem Water Potential ◽

Stem Water

Aim: To evaluate the relationship between carbon isotope ratio (δ13C) and wine grape viticultural and oenological performance in organic farming.Methods and results: The study was carried out for four years in the Chianti Classico wine production district (Central Italy), on five non irrigated vineyards conducted in organic farming. The reference variety was Sangiovese. Eleven sites were chosen for vine monitoring and grape sampling. The performance parameters were alcohol and must sugar content, sugar accumulation rate, mean berry weight, and extractable polyphenols. δ13C, stem water potential, and soil water availability were also monitored. Finally, soil nitrogen as well as yeast available nitrogen in the must were measured. δ13C was directly related to stem water potential and soil water deficit, and indicated a range of water stress conditions from none and moderate to strong. However, its relationship with viticultural and oenological results was contrary to expectation, that is, performance linearly increased along with soil moisture. On the other hand, the worst performance was obtained where both water and nitrogen were more limiting.Conclusions: The unexpected relationship between δ13C and Sangiovese performance was caused by low nitrogen availability. The studied sites all had low-fertility soils with poor or very poor nitrogen content. Therefore, in the plots where soil humidity was relatively higher, nitrogen plant uptake was favoured, and Sangiovese performance improved. Macronutrient being the main limiting factor, the performance was not lower in the plots where soil water availability was relatively larger. Therefore, the best viticultural result was obtained with no water stress conditions, at low rather than at intermediate δ13C values.Significance and impact of the study: Water nutrition is crucial for wine grape performance. δ13C is a method used to assess vine water status during the growing season and to estimate vine performance. A good performance is expected at moderate stress and intermediate δ13C values. A better knowledge of the interaction between water and nutrient scarcity is needed, as it can affect the use of δ13C to predict vine performance.

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