scholarly journals Plant Water Status as an Index of Irrigation Need in Deciduous Fruit Trees

1997 ◽  
Vol 7 (1) ◽  
pp. 23-29 ◽  
Author(s):  
Kenneth A. Shackel ◽  
H. Ahmadi ◽  
W. Biasi ◽  
R. Buchner ◽  
D. Goldhamer ◽  
...  
Keyword(s):  
Water Potential ◽  
Deficit Irrigation ◽  
Shoot Growth ◽  
Water Status ◽  
Plant Stress ◽  
Irrigation Treatment ◽  
Plant Water Status ◽  
Plant Water ◽  
Stem Water Potential ◽  
Stem Water

To be useful for indicating plant water needs, any measure of plant stress should be closely related to some of the known short- and medium-term plant stress responses, such as stomatal closure and reduced rates of expansive growth. Midday stem water potential has proven to be a useful index of stress in a number of fruit tree species. Day-to-day fluctuations in stem water potential under well-irrigated conditions are well correlated with midday vapor-pressure deficit, and, hence, a nonstressed baseline can be predicted. Measuring stem water potential helped explain the results of a 3-year deficit irrigation study in mature prunes, which showed that deficit irrigation could have either positive or negative impacts on tree productivity, depending on soil conditions. Mild to moderate water stress was economically beneficial. In almond, stem water potential was closely related to overall tree growth as measured by increases in trunk cross-sectional area. In cherry, stem water potential was correlated with leaf stomatal conductance and rates of shoot growth, with shoot growth essentially stopping once stem water potential dropped to between −1.5 to −1.7 MPa. In pear, fruit size and other fruit quality attributes (soluble solids, color) were all closely associated with stem water potential. In many of these field studies, systematic tree-to-tree differences in water status were large enough to obscure irrigation treatment effects. Hence, in the absence of a plant-based measure of water stress, it may be difficult to determine whether the lack of an irrigation treatment effect indicates the lack of a physiological response to plant water status, or rather is due to treatment ineffectiveness in influencing plant water status. These data indicate that stem water potential can be used to quantify stress reliably and guide irrigation decisions on a site-specific basis.

scholarly journals Determination of an efficient irrigation schedule for the cultivation of rose cv. Freedom under greenhouse conditions in Colombia

2014 ◽  
Vol 32 (1) ◽  
pp. 95-102 ◽  
Author(s):  
Jhon Jairo Arévalo ◽  
Javier Enrique Vélez S. ◽  
Diego Sebastiano Intrigliolo
Keyword(s):  
Water Potential ◽  
Water Status ◽  
Irrigation Schedule ◽  
Experimental Period ◽  
Plant Water Status ◽  
Base Line ◽  
Plant Water ◽  
Stem Water Potential ◽  
Evaporative Demand ◽  
Stem Water

An experiment on rose (Rosa sp.) cv. Freedom was performed in a greenhouse on the Bogota Plateau, Colombia, to identify an efficient irrigation regime for this crop. The tested treatments were based on three irrigation doses, applying different fractions of the estimated crop evapotranspiration (ETc), calculated using a class A evaporation tank: i) 100% ETc (ETc100), ii) 80% ETc (ETc80) and iii) 70% ETc (ETc70). During the entire experimental period, from mid-May to early September, the crop had a constant production of floral stems. In all of the irrigation treatments, the soil and plant water status were monitored using tensiometers and the midday stem water potential, respectively (ystem). In the fully irrigated roses, the actual water use was determined using a drainage lysimeter in order to obtain the local crop coefficients (Kc) by means of a water balance. From June to August, the obtained monthly Kc values varied between 1.10 and 1.26. Compared to the ETc100 treatment, 14.5 and 21.8% less water was applied in treatments ETc80 and ETc70, respectively. Despite this fact, no statistically significant differences were found among the treatments for rose production or quality. Finally, in the more irrigated roses, tight relationships between the stem water potential and vapor pressure deficit were obtained. The reported base-line equations can be used for predicting the optimum rose plant water status, depending on the environmental conditions. Overall, the reported results can be used for an efficient irritation schedule for rose crops under greenhouse conditions, using the local Kc and direct determinations of plant water status corrected for the evaporative demand.

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

1998 ◽  
Vol 123 (1) ◽  
pp. 150-155 ◽  
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.

scholarly journals An Index for User-Friendly Proximal Detection of Water Requirements to Optimized Irrigation Management in Vineyards

Agronomy ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 323
Author(s):  
Ana Fernandes de Oliveira ◽  
Massimiliano Giuseppe Mameli ◽  
Mauro Lo Cascio ◽  
Costantino Sirca ◽  
Daniela Satta
Keyword(s):  
Water Potential ◽  
Leaf Gas Exchange ◽  
Water Status ◽  
Water Productivity ◽  
Linear Regression Analysis ◽  
Plant Water Status ◽  
Plant Water ◽  
Stem Water Potential ◽  
Water Requirements ◽  
Stem Water

We propose an index for proximal detection of water requirements to optimize the use of water resources in arid and semi-arid wine growing regions. To test the accuracy and representativeness of the proposed irrigation need index (IIN), plant water status and physiological performances were monitored during seasons 2019 and 2020 in two grapevine varieties with different anisohydric degree (Vermentino and Cannonau) grown in 3 sites in Sardinia (Italy). Daily leaf gas exchange curves and stem water potential were recorded. Canopy temperature was monitored, using both thermistor sensors (Tc) and infrared thermometry (IR). Meteorological data, including dry and wet bulb temperatures were collected to compute and parametrize IIN, based on energy balance equation. Vineyard water balance, thermal time and irrigation water productivity were characterized. Linear regression analysis allowed to validate IIN for both varieties and to establish target thresholds for mild, moderate and severe water deficit to optimize irrigation for high yield and quality objectives. IIN well represents plant water status, using either Tc or IR, and allows rapid and easy detection of water and heat stress condition, even when a stricter stomatal control determines slighter variation and lower response of stem water potential, as in plants with low anisohydric degree.

Development of an Artificial Neural Network Approach for Predicting Plant Water Status in Almonds

2019 ◽  
Vol 62 (1) ◽  
pp. 19-32 ◽  
Author(s):  
Julie N. Meyers ◽  
Julie N. Meyers ◽  
Isaya Kisekka ◽  
Shrinivasa K. Upadhyaya ◽  
Gabriela Karoline Michelon ◽  
...  
Keyword(s):  
Neural Network ◽  
Machine Learning ◽  
Artificial Neural Network ◽  
Water Potential ◽  
Water Status ◽  
Plant Water Status ◽  
Plant Water ◽  
Stem Water Potential ◽  
Stem Water ◽  
Artificial Neural

Abstract. Stem water potential (SWP) is a commonly used method for determining plant water status (PWS) but requires a significant amount of time and is tedious to measure. To eliminate the necessity for this fieldwork, artificial neural networks (ANNs) were designed to predict PWS using information that is easier to measure, such as leaf temperature and microclimatic variables including ambient air temperature, relative humidity, incident radiation, and soil water content. To collect these variables, leaf and soil water sensors were placed in a 1.6 ha almond orchard. The sensors were interconnected through a wireless mesh network, which allowed remote data access. SWP values were taken in the field at midday three times a week during the growing season. The ANNs were trained using the Levenberg-Marquardt algorithm with the data divided into 70% training, 15% validation, and 15% test data. Each network contained one hidden layer with one to three hidden neurons. For each unique combination of inputs, the network was retrained five times, and the best network was selected based on the lowest mean squared error for the test data. When compared with multiple linear regression models fitting the same data, the networks consistently resulted in better R2 values, and higher values may be achieved with further optimization. These results suggest that there is potential for machine learning techniques that use ANNs to model the relationship between environmental conditions and PWS, which may be used for predicting acceptable temperature differences from target SWP. Keywords: Almonds, Artificial neural network, Leaf monitor, Machine learning, Plant water status, Precision irrigation, Stem water potential.

scholarly journals Microtensiometers Accurately Measure Stem Water Potential in Woody Perennials

Plants ◽  
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.

scholarly journals 593 A Lightweight, Hand-operated Pressure Chamber for Determining Plant Water Status

HortScience ◽  
2000 ◽  
Vol 35 (3) ◽  
pp. 499B-499
Author(s):  
Ken Shackel ◽  
David Paige
Keyword(s):  
Water Potential ◽  
Water Status ◽  
Irrigation Management ◽  
Nitrogen Pressure ◽  
Irrigation Scheduling ◽  
Pressure Chamber ◽  
Plant Water ◽  
Stem Water Potential ◽  
Stem Water ◽  
Time Required

In a number of tree crops, we have found that the water potential of lower canopy, nontranspiring leaves, measured with the pressure chamber at midday (midday stem water potential), is an excellent index of plant water stress and can be used for irrigation scheduling. Because stem water potential is typically much higher than transpiring leaf water potential, a lower pressure is required for the measurement, allowing us to design and build a lightweight device that could be easily operated by hand. The prototype was designed for pressures up to 2 MPa, which is sufficient for most irrigation conditions. A number of design features were incorporated into the sealing gland to eliminate the need for retightening during the pressurization process, reduce the amount of tissue external to the pressure chamber, and allow a greater visibility of the petiole. Identical values to those obtained with the standard, compressed nitrogen pressure chamber were obtained over the entire 2-MPa range, and the time required using either device under field conditions was the same (about 1 min per measurement). A number of alternative protocols were tested, and we found that even substantial recutting of the petiole had no influence on the measured water potential, contrary to popular belief. We also found that the same sample could be remeasured multiple times (five), with no net change in the water potential, allowing the measurement to be checked if necessary. This device should be of great utility in field irrigation management.

scholarly journals Relationship of stem water potential and leaf conductance to vegetative growth of young olive trees in a hedgerow orchard

2008 ◽  
Vol 59 (3) ◽  
pp. 270 ◽  
Author(s):  
María Gómez-del-Campo ◽  
A. Leal ◽  
C. Pezuela
Keyword(s):  
Water Stress ◽  
Water Potential ◽  
Soil Water ◽  
Vegetative Growth ◽  
Shoot Growth ◽  
Irrigation Treatment ◽  
Leaf Conductance ◽  
Stem Water Potential ◽  
Trunk Diameter ◽  
Stem Water

In 2005, four irrigation treatments were applied to a 3-year-old cv. Cornicabra orchard. In T1, wetted soil volume was maintained close to field capacity by irrigating when soil sensors indicated that soil water potential in the root zone had fallen to –0.03 MPa and 0.06 MPa from spring until 15 August and from 15 August until September, respectively. On those days, 8, 6, 4, and 2 h of irrigation was applied to T1, T2, T3, and T4, so that over the season they received 106, 81, 76 and 31 mm of irrigation, respectively. The high value for T3 was the result of a valve failure on 13 June. Measurements were maintained throughout the experimental period of relative extractable water (REW) to 1 m depth at the wetted volume (0.30 m from a drip emitter), shoot length, trunk diameter, stem water potential (Ψstem) and leaf conductance (gl). The irrigation treatment significantly affected REW (P < 0.10), Ψstem, gl and vegetative growth (P < 0.05). Ψstem, and trunk diameter were the least variable parameters and Ψstem and shoot growth were the most sensitive to water stress. Although T1 received 24% more water than T2, no significant differences were detected in vegetative growth. T2 should be considered the optimum irrigation value. The mean monthly Kc for T2 was 0.086. The failure of the valve in T3 simulated a wet spring followed by limited irrigation. Irrigation applied was similar to T2 but shoot growth stopped one month earlier and lower values of Ψstem and gl were observed after mid August. REW was highly related to vegetative growth, 66% of maximum being achieved at REW 0.53 and 50% at 0.45. gl was independant of plant or soil water status and did not determine vegetative growth. A strong relationship established Ψstem as a good indicator of vegetative growth and hence of water stress. Shoot growth was 66% of maximum at Ψstem –1.5 MPa and 50% at –1.8 MPa.

scholarly journals Terrestrial and Remote Indexes to Assess Moderate Deficit Irrigation in Early-Maturing Nectarine Trees

Agronomy ◽  
2019 ◽  
Vol 9 (10) ◽  
pp. 630 ◽  
Author(s):  
Conesa ◽  
Conejero ◽  
Vera ◽  
Ramírez-Cuesta ◽  
Ruiz-Sánchez
Keyword(s):  
Water Deficit ◽  
Deficit Irrigation ◽  
Water Status ◽  
Fruit Trees ◽  
Plant Water Status ◽  
Plant Water ◽  
Stem Water Potential ◽  
Gas Exchange Parameters ◽  
Water Deficits ◽  
Promising Tool

Monitoring plant water status is relevant for the sustainable management ofirrigation under water deficit conditions. Two treatments were applied to an early-maturingnectarine orchard: control (well irrigated) and precise deficit irrigation (PDI, based on soilwater content thresholds). Moderate water deficits generated by PDI were assessed bycomparing terrestrial: stem water potential (Ψstem) and gas exchange parameters, with remote:canopy temperature, normalized difference vegetation (NDVI), and soil adjusted vegetationindex (SAVI), plant water status indicators. The Ψstem was the only indicator that showedsignificant differences between treatments. NDVI and SAVI at the postharvest period wereappropriate indexes for estimating winter pruning, although they did not serve well as plantstress indicator. Vapor pressure deficit along with Ψstem values were able to predict remotesensing data. Ψstem and canopy to air temperature difference values registered the highestsignal intensity and NDVI the highest sensitivity for detecting water deficit situations. Theresults suggest that care should be taken when using instantaneous remote indicators toevaluate moderate water deficits in deciduous fruit trees; more severe/longer water stressconditions are probably needed. The proposed PDI strategy promoted water saving whilemaintaining yield, and could be considered a promising tool for semi-arid agrosystems.

scholarly journals Improving Almond Productivity under Deficit Irrigation in Semiarid Zones

2011 ◽  
Vol 5 (1) ◽  
pp. 56-62 ◽  
Author(s):  
I.F. García-Tejero ◽  
V.H. Durán-Zuazo ◽  
L.M. Vélez ◽  
A. Hernández ◽  
A. Salguero ◽  
...  
Keyword(s):  
Water Potential ◽  
Water Use ◽  
Deficit Irrigation ◽  
Water Status ◽  
Low Frequency ◽  
Canopy Temperature ◽  
Prunus Dulcis ◽  
Stem Water Potential ◽  
Irrigation Period ◽  
Stem Water

Sustainable water use is one of the greatest challenges of irrigated agricultural systems. This study presents the results related to the agronomic and physiological response to the deficit irrigation of almond trees (Prunus dulcis DA Webb Mill cv. Guara) under semiarid Mediterranean conditions in the Guadalquivir river basin (SW Spain). Two deficitirrigation strategies were tested: i) regulated deficit irrigation (RDI), which was irrigated at 100% of crop evapotranspiration (ETC) throughout the irrigation period, except during the kernel-filling stage, when these trees where irrigated at 30% ETC, and ii) low-frequency deficit irrigation (LFDI), in which trees were subjected to different irrigationrestriction periods, defined in terms of stem water potential at midday (ΨStem). As control, a fully irrigated treatment (C-100) was used, which received irrigation covering the 100% of ETC. The stem water potential (ΨStem), the stomatal conductance (gS), the photosynthesis rate (Pn) and canopy temperature (TC) were monitored, revealing significant differences mainly in LFDI in comparison with C-100. Also, highly significant relationships were found among plant physiological parameters, showing that the water status is strongly related to the crop water availability. On other hand, in terms of nut yield, there was a notable improvement under LFDI compared with RDI, with increases of 16% in relation to C-100, and with water savings of close to 170 mm. Thus, these findings demonstrate that the LFDI is a sustainable strategy to improve almond productivity as well as water-use efficiency under limited water resources.

scholarly journals Plant Water Status as an Index of Irrigation Needs in Deciduous Fruit Trees

HortScience ◽  
1995 ◽  
Vol 30 (4) ◽  
pp. 905B-905 ◽  
Author(s):  
Kenneth A. Shackel
Keyword(s):  
Stress Responses ◽  
Deficit Irrigation ◽  
Shoot Growth ◽  
Stomatal Closure ◽  
Plant Stress ◽  
Fruit Trees ◽  
Soluble Solids ◽  
Soil Conditions ◽  
Plant Water ◽  
Stem Water Potential

To be useful for indicating plant water needs, any measure of plant stress should be closely related to some of the known short- and medium-term plant stress responses, such as stomatal closure and reduced rates of expansive growth. Midday stem water potential (SWP) has proven to be a useful index of stress in a number of fruit trees. Day-to-day fluctuations in SWP under well-irrigated conditions is well-correlated to midday vapor pressure deficit, and hence can be used to predict a non-stressed baseline. Measurement of SWP helped to explain the results of a 3-year deficit irrigation study in mature prunes, which showed that deficit irrigation could have either positive or negative impacts on tree productivity, depending on soil conditions. Mild to moderate water stress was economically beneficial. In cherry, SWP was correlated to both leaf stomatal conductance and rates of shoot growth, with shoot growth essentially stopping once SWP dropped to between –1.5 to –1.7 MPa. In pear, increased fruit size, decreased fruit soluble solids, and increased green color were all associated with increases in SWP.

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