scholarly journals Irrigation Water Management for Pecans in Humid Climates

HortScience ◽  
2015 ◽  
Vol 50 (7) ◽  
pp. 1070-1074 ◽  
Author(s):  
Lenny Wells
Keyword(s):  
Soil Moisture ◽  
Water Stress ◽  
Water Potential ◽  
Irrigation Water ◽  
Irrigation Schedule ◽  
Irrigation Scheduling ◽  
Stem Water Potential ◽  
Crop Load ◽  
Early Season ◽  
Stem Water

Pecan [Carya illinoinensis (Wangenh.) K. Koch] tree stem water potential (ψ), shoot length, nut yield, and nut quality for the following treatments were evaluated in a commercial pecan orchard in Berrien County, GA; 1) current recommended irrigation schedule, 2) a reduced early season irrigation schedule, and 3) non-irrigated control. Water Stress on pecan occurred at ≈−0.78 MPa using the pressure chamber to measure stem water potential. Regression analysis suggests that irrigation scheduling for mature pecan trees may be needed when volumetric water content reaches 10% on Tifton loamy sand soil. Water stress in pecan is correlated with soil moisture from budbreak through the end of nut sizing. Pecan trees bearing a moderate to heavy crop load may undergo water stress during the kernel-filling stage regardless of soil moisture level. Therefore, it is suggested that water stress during the kernel-filling period is a function of nut development, crop load, or both in addition to soil moisture. The reduced early season irrigation schedule provided a 38% reduction in irrigation water use with no significant effect on pecan tree water stress, yield, or quality, suggesting that pecan trees can tolerate moderate early season water stress with no effect on pecan yield or quality under southeastern U.S. environmental conditions.

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

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

<p>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 (<em>Citrus paradisi</em> 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 ​​of R<sup>2</sup> around 0.7 in all cases; the best fit corresponded to SWP = - 4.869 + 15.765 NDGI - 14.283 NDGI<sup>2</sup> (R<sup>2 </sup>= 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.</p><p>Funding:</p><p>-WATER4EVER is funded by the European Commission under the framework of the ERA-NET COFUND WATERWORKS 2015 Programme</p><p>-RIS3MUR REUSAGUA is funded by the Consejería de Empresa, Industria y Portavocía of the Murcia Region under the Feder Operational Program 2014-2020</p>

scholarly journals Water Stress Increases Sunburn in ‘Cripps’ Pink’ Apple

HortScience ◽  
2013 ◽  
Vol 48 (4) ◽  
pp. 444-447 ◽  
Author(s):  
Brian Makeredza ◽  
Michael Schmeisser ◽  
Elmi Lötze ◽  
Willem J. Steyn
Keyword(s):  
Soil Moisture ◽  
Water Stress ◽  
Surface Temperature ◽  
Water Potential ◽  
Southern Hemisphere ◽  
Stem Water Potential ◽  
Irrigation Level ◽  
Effect Of Water ◽  
Stem Water ◽  
Fruit Surface

An experiment that entailed the manipulation of irrigation was carried out to assess the effect of water stress on sunburn development in ‘Cripps’ Pink’ apples. Normal irrigation, half irrigation, and no irrigation treatments were applied for 15 days starting on 14 Mar. 2010 (Southern hemisphere). Stem water potential, fruit surface temperature (FST), sunburn incidence, and sunburn severity were measured. Sunburn was also categorized into browning, necrosis, or bleaching sunburn types. Fully exposed fruit without prior sunburn symptoms were tagged for progressive sunburn assessments, whereas sunburn was also assessed at harvest for all fruit per tree. Soil moisture and stem water potential decreased, whereas FST, sunburn incidence, and severity increased linearly with a decrease in irrigation level. Sunburn necrosis increased with increasing water stress. In conclusion, water stress aggravates sunburn development under conditions conducive for its development by increasing FST.

scholarly journals Water Stress and Crop Level Interactions in Relation to Nectarine Yield, Fruit Size Distribution, and Water Potentials

1999 ◽  
Vol 124 (2) ◽  
pp. 189-193 ◽  
Author(s):  
A. Naor ◽  
I. Klein ◽  
H. Hupert ◽  
Y. Grinblat ◽  
M. Peres ◽  
...  
Keyword(s):  
Water Stress ◽  
Water Potential ◽  
Size Distribution ◽  
Total Yield ◽  
Fruit Size ◽  
Irrigation Scheduling ◽  
Stem Water Potential ◽  
Water Potentials ◽  
Stem Water ◽  
Irrigation Treatments

The interactions between irrigation and crop level with respect to fruit size distribution and soil and stem water potentials were investigated in a nectarine (Prunus persica (L.) Batsch. `Fairlane') orchard located in a semiarid zone. Irrigation treatments during stage III of fruit growth ranged from 0.62 to 1.29 of potential evapotranspiration (ETp). Fruit were hand thinned to a wide range of fruit levels (200 to 1200 fruit/tree in the 555-tree/ha orchard). Total yield did not increase with increasing irrigation rate above 0.92 ETp in 1996 and maximum yield was found at 1.06 ETp in 1997. Fruit size distribution was shifted towards larger fruit with increasing irrigation level and with decreasing crop level. The two highest irrigation treatments had similar midday stem water potentials. Our findings indicate that highest yields and highest water use efficiency (yield/water consumption) are not always related to minimum water stress. Total yield and large fruit yield were highly and better correlated with midday stem water potential than with soil water potential. This confirms other reports that midday stem water potential is an accurate indicator of tree water stress and may have utility in irrigation scheduling.

scholarly journals Impacts of water stress, environment and rootstock on the diurnal behaviour of stem water potential and leaf conductance in pistachio (Pistacia vera L.)

2016 ◽  
Vol 14 (2) ◽  
pp. e0804 ◽  
Author(s):  
Houssem Memmi ◽  
Jose F. Couceiro ◽  
Carmen Gijón ◽  
David Pérez-López
Keyword(s):  
Water Stress ◽  
Water Potential ◽  
Water Status ◽  
Irrigation Scheduling ◽  
Leaf Conductance ◽  
Irrigation Season ◽  
Stem Water Potential ◽  
Stem Water ◽  
Diurnal Behaviour ◽  
Pistachio Trees

Little information is available on the diurnal behaviour of water potential and leaf conductance on pistachio trees despite their relevance to fine tune irrigation strategies. Mature pistachio trees were subject to simultaneous measurements of stem water potential (Ψx) and leaf conductance (gl) during the day, at three important periods of the irrigation season. Trees were grown on three different rootstocks and water regimes. An initial baseline relating Ψx to air vapor pressure deficit (VPD) is presented for irrigation scheduling in pistachio. Ψx was closely correlated with VPD but with a different fit according to the degree of water stress. No evidence of the variation of Ψx in relation to the phenology of the tree was observed. Furthermore, midday Ψx showed more accuracy to indicate a situation of water stress than predawn water potential. Under well irrigated conditions, gl was positively correlated with VPD during stage II of growth reaching its peak when VPD reached its maximum value (around 4 kPa). This behaviour changed during stage III of fruit growth suggesting a reliance of stomatal behaviour to the phenological stage independently to the tree water status. The levels of water stress reached were translated in a slow recovery of tree water status and leaf conductance (more than 40 days). Regarding rootstocks, P. integerrima showed little adaptation to water shortage compared to the two other rootstocks under the studied conditions.

scholarly journals Stem-water Potential as a Sensitive Indicator of Water Stress in Prune Trees (Prunus domestica L. cv. French)

1992 ◽  
Vol 117 (4) ◽  
pp. 607-611 ◽  
Author(s):  
Harold McCutchan ◽  
K.A. Shackel
Keyword(s):  
Soil Moisture ◽  
Water Stress ◽  
Soil Texture ◽  
Relative Sensitivity ◽  
Irrigation Scheduling ◽  
Stress Effect ◽  
Stem Water Potential ◽  
Irrigation Interval ◽  
Stem Water ◽  
Daily Variability

The relative sensitivity of plant- and soil-based measures of water availability were compared for prune trees subjected to a range of irrigation regimes under field conditions. Over the growing season, leaf- and stem-water potentials (ψ) measured at midday exhibited clear differences between frequently irrigated trees and unirrigated trees that were growing on stored soil moisture. Stem ψ was less variable than leaf ψ, and the daily variability in stem ψ was closely related to daily variability in evaporative demands, as measured by vapor pressure deficit (VPD). As a result of lower variability, stem ψ reflected the small stress effect of a moderate, 50% soil moisture depletion irrigation interval, whereas leaf ψ did not. The relation between soil water content and estimated orchard evapotranspiration (ET) was influenced by local differences in soil texture within the experimental plot. The relation between stem ψ and ET, however, was not influenced by soil texture and, in addition, was very similar to the relation between stem ψ and leaf stomatal conductance. Both relationships indicated that a 50% reduction in leaf and canopy level water loss characteristics was associated with relatively small reductions (0.5 to 0.6 MPa) in stem ψ. Stem ψ appears to be a sensitive and reliable plant-based measure of water stress in prune and maybe a useful tool for experimental work and irrigation scheduling.

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

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

<p>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.</p><p>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.</p><p>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.</p><p>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.</p><p>Determination coefficients of r<sup>2</sup>=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.</p><p>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’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, (r<sup>2</sup>=0.60 NDWI in 2018), as well as greater differences in terms of water stress presented in the vineyard.</p><p>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.</p>

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

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

<p>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.</p><p>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’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.</p><p>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.</p><p><strong>ACKNOWLODGEMENTS</strong></p><p>Financial 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.</p>

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