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Abstract
Water stress integral (SΨ), the cumulative integral of pre-dawn leaf water potential over any chosen period of time, was estimated from measurements
of pre-dawn water potential made every two weeks in a Pinus radiata D. Don plantation near Canberra, Australia. Also measured were final length of current-season needles and annual stem basal
area increment. Data were gathered over a 4-year period from a control plot, a fertilized plot, an irrigated plot, and two
plots that were both fertilized and irrigated. Among years and treatments, annual basal area increment varied over a threefold
range. Of this variation, 91% was accounted for by variation in SΨ for the entire year, during every month of which stem diameter growth occurred. Of variation in annual needle elongation,
90% was accounted for by variation in SΨ from late August to late February, which was the period of needle growth. In dry years, the annual value of SΨ in non-irrigated plots was mainly determined by soil water content, but in wet years in non-irrigated plots, and in all years
in irrigated plots, it was closely correlated with tree nutrient status (r2 = 0.81).
... The stress factor is the area limited by the measured values of the leaf water potential seasonal pattern and a constant value. Such an approach would include the level and duration of water stress [26]. Changes to the constant value, which is the reference, would affect the result obtained. ...
... Rudich et al. [25] used −0.6 MPa as a threshold because they considered this value to be the beginning of severe water stress conditions. Coyago-Cruz et al. [24] suggested using the stress integral, with the most positive value measured in the experiment (−0.2 MPa in this work), as recommended by Myers [26]. In fact, this reference value would be variable because the leaf water potential was related to the evaporative demand [4]. ...
... The stress Integral (SI) was estimated using single leaf water potential data, according to Myers [26]. This approach was similar to the ones suggested by Rudich et al. [25] and estimated the cumulative effect of water stress. ...
The scarcity of water resources affects tomato production. Deficit irrigation may optimize water management with only a low reduction in yield. Deficit irrigation scheduling based on applied water presented no clear conclusions. Water stress management based on plant water status, such as water potential, could improve the scheduling. The aim of this work was to evaluate the physiological and yield responses of different tomato cultivars to deficit irrigation. Three experiments were carried out in 2020 and 2022 at the University of Seville (Spain). “Cherry” and “chocolate Marmande” cultivars with an indeterminate growth pattern were grown in a greenhouse. Treatments were: Control (full irrigated) and Deficit. Deficit plants were irrigated based on water potential measurements. Moderate water stress did not significantly reduce the yield, although it affected other processes. Fruit size and total soluble solids were the most sensitive parameters to water stress. The latter increased only when persistent water stress was applied. However, truss development and fruit number were not affected by the level of water stress imposed. Such results suggest that moderate water stress, even in sensitive phenological stages such as flowering, would not reduce yield. Deficit irrigation scheduling based on plant water status will allow accurate management of water stress.
... Moreover, in late cultivars this period can last up to six months, thus increasing the potential for reducing pressure on water resources by deficit irrigation strategies (Pagán et al., 2022). Nevertheless, when the irrigation thresholds described above are exceeded, it can affect productivity, vegetative growth, or fruit quality in the short or long term Berríos et al., 2023;Blanco et al., 2019;Conesa et al., 2015;Gasque et al., 2016;Myers, 1988;Pérez-Pastor et al., 2016Temnani et al., 2022). The most widely validated indicator for determining trees water status is the stem water potential (Ψ s ), due to its high sensitivity to the irrigation regime, soil water status and evaporative demand (Naor, 2000;Pérez-Pastor et al., 2016;Shackel et al., 1997). ...
... The most widely validated indicator for determining trees water status is the stem water potential (Ψ s ), due to its high sensitivity to the irrigation regime, soil water status and evaporative demand (Naor, 2000;Pérez-Pastor et al., 2016;Shackel et al., 1997). The intensity of the stress can also be quantified through the water stress integral based on Ψ s to compare the effect of different treatments on the crop (Myers, 1988). ...
... Four shaded and close to main branches adult leaves per replicate (n = 12 per treatment) were selected and covered with an aluminized bag 1.5 h before measurement. The water stress integral for each treatment was determined respect to well-irrigated reference trees irrigated at 100 % of the ET c (n = 12) in the same experimental conditions and date from Eq. (1) (Myers, 1988): ...
The diversified cropping systems has several environmental benefits, but there is no certainty about their effect on the water status of trees, especially in areas with permanent low availability of irrigation water. Therefore, our objective was to evaluate the effect of the establishment of diversified cropping systems in a traditional monoculture (MC) of adult mandarin trees on its water status and yield under sustained deficit irrigation (SDI) and regulated deficit irrigation (RDI). Six treatments were tested during three consecutive seasons: (i) a mandarin monoculture under SDI (MC-SDI), with permanent bare alleys and irrigated at ~70 % ET c during the entire season (actual amount of irrigation water available in the area); (ii) a diversified mandarin crop (D1-SDI), irrigated as MC-SDI, with a rotation of fava bean and barley/vetch in the alleys; and (iii) a second diversified mandarin crop (D2-SDI), irrigated as MC-SDI, with a seasonal rotation of fava bean, purslane and cowpea. Additionally, three RDI treatments were evaluated, denoted as (iv) MC-RDI, (v) D1-RDI and (vi) D2-RDI, irrigated as MC-SDI, except during the stage II of fruit growth, when it was reduced by 50 % with an irrigation threshold of a solar midday stem water potential of ~-1.5 MPa. The mandarin yield was not affected by the effect of diversified cropping systems, but the RDI reduced it on average by 30.1 % with respect to SDI. The alley cropping of fava bean and barley/vetch during winter and spring under sustained deficit irrigation conditions reduced the water stress intensity of mandarin trees by 26.9 % over the entire season, while cultivation of purslane or cowpea during summer increased it by 60-144 %. Both diversifications required a greater amount of water than the monoculture, in these terms an additional reduction in the irrigation of mandarin trees, as in the RDI treatment, allowed to solve this additional water requirement, but promoted an increase in the water stress intensity of the trees, which may affect their productivity in the mid and long-term.
... Pagán et al. [35] stated in mandarin, that it was possible to apply RDI during the second stage of fruit growth until the slowing of trunk growth. In terms of stress intensity, using the Ψ s -based water stress integral (S Ψ ) [36], we can quantify the stress applied to the crop and thus be able to extrapolate our results to other agroclimatic zones. In this sense, an irrigation threshold of a Ψ s of −1.8 MPa and a cumulative S Ψ close to 28 MPa day until the fruits reach 60% of their final size should be considered for RDI in mandarin [35,37]. ...
... The water stress integral for each deficit irrigation treatment was determined with respect to the values of the CTL treatment from Equation (1) [36]: ...
... For this reason, knowledge of the threshold values of Ψ s , which is the most widely used indicator of plant water status [63] due to its high sensitivity to water stress [33,64], would greatly facilitate a more efficient scheduling of deficit irrigation. For this reason, the use of S Ψ , from the Ψ s values, would allow us to quantify the water stress to which a plant is submitted in a phenological phase, previously delimited through the thermal integral [36]. ...
Irrigated agriculture is facing a serious problem of water scarcity, which could be mitigated by optimizing the application of regulated deficit irrigation (RDI) strategies. For this reason, the aim of our study was to determine irrigation thresholds based on direct water status indicators of apricot trees under RDI to maximize water productivity. Three treatments were tested: (i) Control (CTL), irrigated at 100% of the crop evapotranspiration (ETc) during the entire crop cycle; (ii) RDI1, irrigated as CTL, except during fruit growth stages I–II when irrigation was reduced by 20% of CTL, and during late post-harvest, with an irrigation threshold of a moderate water stress of −1.5 MPa of stem water potential (Ψs); and (iii) RDI2, irrigated as RDI1, but during late post-harvest using a severe water stress threshold of −2.0 MPa of Ψs. As the irrigation scheduling of RDI1 and RDI2 did not affect yield and fruit quality, the crop water productivity was increased by 13.2 and 25.6%, respectively. This corresponded to 1124 and 2133 m3 ha−1 of water saved for RDI1 and RDI2. A water stress integral of 30.2 MPa day during post-harvest could be considered optimal since when 41 MPa day was accumulated, vegetative growth was reduced by 35%. The non-sensitive periods to water deficit were delimited by the accumulation of growing degree days (GDD) from full bloom, the end of fruit growth stages I–II corresponded to an accumulation of 640 °C GDD, and the beginning of the late post-harvest to an accumulation of 1840 °C GDD.
... Short term reactions are linked to physiological responses and long-term effects are related to morphology and growth. Thus, the relationship between plant water status (e.g., leaf water potential) and forest yield is necessary to associate the effects of water status on plant development, known as the water stress integral (WSI) (Myers, 1988). The WSI consists of the summation of the leaf water potential at defined intervals over the measurement period. ...
... The WSI consists of the summation of the leaf water potential at defined intervals over the measurement period. Larger absolute values of WSI represent larger amounts of accumulated water stress (Myers, 1988). ...
... These dates coincided with different periods of rainfall (PPT) and temperature (T) at the experimental site ( Figure 1). Following Myers (1988), we calculated the cumulative water stress integral (WSI) as the cumulative integral of Ψ pd (Galindo et al., 2017) over the entire growth period: ...
... Leaves were covered with an aluminized bag 2 h before measurement. The water stress integral for RDI treatment was determined with respect to the season maximum value of the CTL treatment from Eq. (1) (Myers, 1988): ...
... Despite its low temporal and spatial scale, Ψ s is a direct measurement of plant water status with a high sensitivity to the irrigation regime, environmental conditions, and soil water availability (Naor, 2000;Ortuño et al., 2009;Shackel et al., 1997). Furthermore, the S Ψ (Myers, 1988) allows us to quantify the water stress applied to a crop and can be extrapolated to other agro-climatic zones. Likewise, when a seasonal accumulated water stress integral (S Ψ ) of 58 MPa day was reached the trunk growth was reduced, while it was not significantly affected when the S Ψ was 30 MPa day (Figs. ...
... Following Myers [35], the effect of water deficit duration and intensity was accounted for by the S ψ computed as the summation of the difference in the average of two consecutive measurements of Ψ stem (ψ i,i+1 ) and the least negative value registered during the season (c = −0.35 MPa in 2018 and 2019, and c = −0.28 ...
... Unlike most of the works found in the bibliography that estimated water status using punctual measures such as stem or leaf water potential, in our study the S ψ was used. This variable enabled the analysis of the effect of the cumulative water deficit duration and intensity throughout the growing season considering midday Ψ stem measurements over a chosen period of time [35], coinciding with the fact that the accumulated effects of water stress are shown in plant tissues affecting the spectral response of leaves [15,55]. Some studies have employed this parameter, as an index of water stress, and it was correlated with volume growth, pre-dawn xylem water potential, soil volumetric water content [11], productivity [56], and mortality [57]. ...
The development of unmanned aerial vehicles (UAVs) and light sensors has required new approaches for high-resolution remote sensing applications. High spatial and temporal resolution spectral data acquired by multispectral and conventional cameras (or red, green, blue (RGB) sensors) onboard UAVs can be useful for plant water status determination and, as a consequence, for irrigation management. A study in a vineyard located in south-eastern Spain was carried out during the 2018, 2019, and 2020 seasons to assess the potential uses of these techniques. Different water qualities and irrigation application start throughout the growth cycle were imposed. Flights with RGB and multispectral cameras mounted on a UAV were performed throughout the growth cycle, and orthoimages were generated. These orthoimages were segmented to include only vegetation and calculate the green canopy cover (GCC). The stem water potential was measured, and the water stress integral (Sψ) was obtained during each irrigation season. Multiple linear regression techniques and artificial neural networks (ANNs) models with multispectral and RGB bands, as well as GCC, as inputs, were trained and tested to simulate the Sψ. The results showed that the information in the visible domain was highly related to the Sψ in the 2018 season. For all the other years and combinations of years, multispectral ANNs performed slightly better. Differences in the spatial resolution and radiometric quality of the RGB and multispectral geomatic products explain the good model performances with each type of data. Additionally, RGB cameras cost less and are easier to use than multispectral cameras, and RGB images are simpler to process than multispectral images. Therefore, RGB sensors are a good option for use in predicting entire vineyard water status. In any case, field punctual measurements are still required to generate a general model to estimate the water status in any season and vineyard.
... At least two shaded and mature leaves were selected in each replicate (n = 8 and n = 6 leaves per irrigation treatment for the ES1 and ES2, respectively), with the leaves placed in aluminized plastic bags for at least 2 h prior to the measurements. Although vines under SDI and NI irrigation practices were subjected to water stress during the entire crop cycle, the intensity of water stress endured by each irrigation treatment was estimated with the water stress integral (SΨ s ) accumulated during the post-veraison period, using the equation defined by Myers [39]: ...
... In this sense, the non-critical period for a deficit irrigation strategy in 'Crimson Seedless' is during post-veraison, with a stem water potential (Ψ s ) threshold of −1.2 MPa [43]. From the maximum Ψ s , it is possible to quantify the water stress intensity accumulated during the established deficit period [39], allowing the extrapolation of the irrigation protocols to other agro-climatic zones. ...
The aims of this work were modelling the effect of water stress intensity during post-veraison on table grape quality and yield, as well as predicting berry quality at harvest using a machine learning algorithm. The dataset was obtained by applying different irrigation regimes in two commercial table grape vineyards during seven growing seasons. From these data, it was possible to train and validate the predictive models over a wide range of values for the independent (water stress intensity and fruit load) and dependent (firmness and berry color) variables. The supervised learning algorithm Gaussian Process Regression allowed us to predict the variables with high accuracy. It was also determined that a reduction in irrigation of up to 40% during post-veraison, compared to vines without water limitations, and the accumulation of the water stress integral of up to 30 MPa per day, linearly increase the irrigation water use efficiency (IWUE) and promote higher berry color and firmness. The severe water scarcity and the increasing uncertainty about the irrigation water availability for the season that farmers are facing highlight the advantage of incorporating these validated techniques into agricultural decision making, as they allow for the planning of cultural practices and criteria to increase the IWUE and crop sustainability.
... The leaf water potential is considered equivalent to the stem water potential when leaf transpiration was prevented (Choné et al., 2001). The Ψ pd was used to calculate a water stress integral (S Ψ ) as proposed by Meyers (1988). The S Ψ expresses the stress intensity of the vine by integrating the duration of water status below a maximum value of Ψ pd . ...
... Based on Ψ pd values, only two levels of water deficit could be defined with severe water deficit for 101-14 MGt and 41B MGt (Ψ pd < -0.6 MPa) and mild (-0.3 to -0.5 MPa) for Riparia Gloire, Kober 5BB and 3309C, confirming that Ψ stem is a more sensitive indicator of water status than Ψ pd (Choné et al., 2001;Patakas et al., 2005;Souza et al., 2009). S Ψ was shown to be a useful parameter for estimating and integrating water stress in different crops (Meyers, 1988), including grapevine (Souza et al., 2005a). Indeed in this study, S Ψ followed similar patterns as Ψ stem values for the different rootstock combinations. ...
Under the global warming scenario, water scarcity is expected to intensify in most grape-growing regions. The use of drought-tolerant rootstocks is considered a useful tool to mitigate the negative effects of soil water deficit on vine functioning. Differences in leaf gas exchange, plant water status, specific hydraulic conductivity in petioles (K petiole), xylem vessel size and vegetative vigour of field-grown Pinot noir grafted onto five rootstocks (3309C, 101-14 MGt, Kober 5BB, Riparia Gloire de Montpellier, 41B MGt) were investigated during one season under water deficit in Switzerland. The water deficit was imposed by installing waterproof and non-reflecting plastic sheets on the soil from March to harvest (September) to avoid rainfall infiltration. Rootstocks had stronger effects on vine water status than on gas exchanges. During the grape ripening stage, vines grafted onto 41B MGt and 101-14 MGt were characterised by more severe water stress as shown by the lowest values of pre-dawn leaf (Ψ pd), stem water potential (Ψ stem) and water stress integral (S Ψ), whereas 3309C and Kober 5BB rootstocks induced milder effects. Significant differences in photosynthesis (A), stomatal conductance (gs) and transpiration (E) were only observed between vines grafted onto 41B MGt and 3309C at later stages of ripening. Changes induced by rootstocks in shoot vigour, K petiole and the number and size of xylem vessels in petioles and stems were correlated to differential responses of Pinot noir to water deficit. The increased vegetative vigour induced by 3309C and Kober 5BB was associated with the highest K petiole , xylem vessel size and a good plant water status of Pinot noir under low soil water availability. Kober 5BB induced the highest yield, probably due to the better vine water status, whereas vines grafted onto 41B MGt showed the lowest malic acid content and yeast assimilable nitrogen in berries.
... The cumulative effect of the water deficit was determined as the water-stress integral (S Ψ ) calculated, as defined by Myers (1988) [81], as the sum of the mean difference between two consecutive measurements of water potential (Ψ i,i+1 ) and the maximum (least negative) value recorded during the study period(c), multiplied by the number of days in the interval between one measurement and the next (n) (1). ...
... The cumulative effect of the water deficit was determined as the water-stress integral (S Ψ ) calculated, as defined by Myers (1988) [81], as the sum of the mean difference between two consecutive measurements of water potential (Ψ i,i+1 ) and the maximum (least negative) value recorded during the study period(c), multiplied by the number of days in the interval between one measurement and the next (n) (1). ...
One alternative for adapting viticulture to high temperatures and the scarcity of water is the development of new varieties adapted to such conditions. This work describes six new genotypes, derived from “Monastrell” × “Cabernet Sauvignon” (MC16, MC19, MC72, MC80) and “Monastrell” × “Syrah” (MS104, MS49) crosses, grown under deficit irrigation and rainfed conditions in a semi-arid wine-producing area (Murcia, southeastern Spain). The effect of genotype, year, and irrigation treatment on the phenological, productiveness, morphological, and grape quality data was evaluated. The study material was obtained and selected as part of a breeding program run by the Instituto Murciano de Investigación y Desarollo Agrario y Medioambiental (IMIDA). The results obtained show that under rainfed conditions, the values for productive variables decreased, while those referring to the phenolic content increased. Notable variation in the parameters evaluated was also seen for the different genotypes studied. The behavior of the genotypes MC80 and MS104 under rainfed conditions was noteworthy. In addition to maintaining very adequate yields, phenolic contents, must pH, and total acidity values, MC80 fell into the best ‘phenolic quality group’ and MS104 returned a low º°Baumé value, ideal for the production of low-alcohol-content wines. These genotypes could favor the development of sustainable quality viticulture in dry and hot areas.
... The integrated stem water potential (Int(Ψ s )) was estimated to account for both the intensity and the duration of water stress. Int(Ψ s ) was calculated using Eq.1, as defined by Myers (1998). ...
In recent years, more intensive production systems have been developed, coinciding with a growing scarcity of water resources. This context underscores the imperative of prioritizing water productivity (WP) as a critical factor in choosing the optimal production system to minimize agricultural water use. This study aims to contribute by evaluating WP in almond orchards under four production systems: open vase with severe pruning (open vase), open vase with minimal pruning (open vase (MP)), central axis and hedgerow. Three irrigation treatments were applied over two consecutive growing seasons: fully irrigated, mild stress and severe stress. Crop transpiration was monitored over the two years using both sap flow sensors and the two-source energy balance (TSEB) model with remote sensing. The severe stress treatment exhibited a notable reduction in kernel yield and nut load of 31.6 % and 34.5 %, respectively, in the second year of water deficit. The hedgerow system tended to have similar kernel yield to the open vase (MP) and central axis systems, and higher compared to the open vase system. Additionally, both transpiration measurement methods revealed that hedgerow exhibited lower transpiration rates across all irrigation treatments. Therefore, the highest WP was observed in the hedgerow system throughout both studied years. Similar findings were derived from the analysis of long-term data. Our findings indicate that the hedgerow production system had the highest WP, averaging 0.43 kg m−3 historically, compared to 0.33 kg m−3 for the open vase, 0.34 kg m−3 for the open vase (MP), and 0.36 kg m−3 for the central axis systems.
... Specifically, trial 1 was subjected to a higher WSI than trial 2, oscillating their values for the whole season between 3034.12 and 1299.32 kPa day, respectively (Figure 2). Up to now, the WSI index has been used to quantify the water stress to which a crop has been subjected in a period of water deficit, according to Myers [59]. In this study, we applied this methodology to the Ψ m values, obtaining a differentiation between the two trials. ...
Although advanced production systems have been developed in the last 20 years, water scarcity is still a growing problem in agriculture. This study aims to evaluate the effect of different strategies that combine the application of seaweed and microbial biostimulants with regulated deficit irrigation (RDI) strategies on the irrigation water productivity (WPI), fruit quality parameters and soil enzymatic activity in pepper plants (Capsicum annum sp.) under two commercial greenhouse conditions. In each trial, two treatments were applied: (i) irrigation according to Farmer criteria without biostimulant applications and (ii) a combined treatment of RDI and the same biostimulation program, composed of Bacillus paralicheniformis and Ascophillum nodosum extracts. RDI was applied in different phenological stages in each greenhouse after the establishment until the 1st harvest in trial 1 or during the ripening and harvest period in trial 2. On average, the irrigation was reduced by 600 m3 ha−1 compared to the Farmer irrigation schedule. In both trials, biostimulation promoted an increase in fruit numbers, punctually in trial 1, leading to yield precocity, or generally in trial 2, obtaining a higher yield. Globally, WPI was increased when RDI was combined with biostimulation. This combined treatment also enhanced the root water absorption and improved the soil enzymatic activity in both greenhouses, suggesting that nutrients in the soil would become more available to plants. Thus, the combined action of biostimulation under different RDI strategies has been proved to be a useful strategy to improve agricultural sustainability.
... The measurements were carried out between 2:00 AM and 4:00 AM immediately after detaching the leaf from the plant. A water stress index (WSI) was calculated from the sum of all water potentials over the seasons as Myers (1988). As WSI is expressed in absolute values (MPa day-1). ...
https://theses.hal.science/tel-04543691
During eight consecutive seasons (2014-2021) the intra-plot heterogeneity of vigor in a cv. Tannat vineyard in Uruguay was studied. Such variability was assessed during three years (2015, 2016 and 2017) using the Normalized Difference Vegetation Index (NDVI). High-resolution (0.2 m) multispectral images were obtained over the ground to define contrasting vigor zones: high (HV) and low (LV). In winter 2020, trunk diameter was assessed to corroborate the interannual stability of vigor, and positive correlations were established between NDVI and vegetative growth parameters. A complete description of soil physical and chemical parameters was carried out. Climate data, vegetative growth, yield and grape composition were used. In addition, site-specific management techniques were employed according to vigor zone to influence yield and grape quality and reduce heterogeneity. For HV, treatments were aimed at reducing water and nitrogen inputs and improving microclimatic conditions in the cluster zone. In LV, on the other hand, treatments were aimed at increasing vegetative growth and yield with water and nitrogen supplementation. Although a 1 ha plot can be considered homogeneous from a topographic, edaphological and climatic point of view, this study demonstrated the existence of great variability in soil variables, production parameters and grape composition. The HV zone was associated with higher levels of leaf area, pruning weight, yield (higher berry and bunch weight) and bunch disease incidence than the LV zone. These HV zone characteristics were the result of a deeper and more structured soil, with higher organic matter content, nitrogen reserves and clay content, and abundance of montmorillonite-type clay. The LV zone, was distinguished by a shallower and more compact soil which negatively conditioned root growth. New information was provided on the interaction of the soil-plant-atmosphere system. In particular, the dominant role of water availability in the first place and soil nitrogen availability in the second place in establishing plant vigor. The gradient of vine vigor and yield between the two zones remained stable over the years, regardless of climatic conditions. This indicates that soil characteristics can mitigate or enhance the effects caused by climatic conditions. The determination (possible by remote sensing) of the vigor zones of a plot is a prerequisite for proposing soil and crop management practices that optimize the use of resources and ensure the economic and environmental sustainability of wine production.
... The measurement procedures were described previously [23]. To indicate the cumulative grapevine water status information, Ψ stem integrals (Ψ stem Int) were calculated by using natural cubic splines [24]. The sum of the values was divided by the number of days between the first and the last measurements in each year to make the data comparable to each individual measurement. ...
The spatial variability in vineyard soil might negatively affect wine composition, leading to inhomogeneous flavonoid composition and aromatic profiles. In this study, we investigated the spatial variability in wine chemical composition in a Cabernet Sauvignon (Vitis vinifera L.) vineyard in 2019 and 2020. Because of the tight relationships with soil profiles, mid-day stem water potential integrals (Ψstem Int) were used to delineate the vineyard into two zones, including Zone 1 with relatively higher water stress and Zone 2 with relatively lower water stress. Wine from Zone 2 generally had more anthocyanins in 2019. In 2020, Zone 1 had more anthocyanins and flavonols. Zone 2 had more proanthocyanidin extension and terminal subunits as well as total proanthocyanidins in 2020. According to the Principal Component Analyses (PCA) for berry and wine chemical composition, the two zones were significantly different in the studied wine aromatic compounds. In conclusion, this study provides evidence of the possibility of managing the spatial variability of both wine flavonoid composition and aromatic profiles through connecting vineyard soil variability to grapevine season-long water status.
... Such a condition is associated with the loss of a significant part of the root system when taking out seedlings, as well as stress caused by insufficient moisture and nutrients, which can often lead to higher mortality in the first growing season (Rietveld 1989, Struve and Joly 1992, Jacobs et al. 2005. Also, dense weeds quickly overgrow the seedlings, overshade them, and thereby affect the process of photosynthesis, which affects their survival and height growth (Myers 1988). Oak seedlings are particularly sensitive to competition from weeds, shrubs and other competitive species that reduce available sunlight, moisture and nutrients in the soil (Matić 1996). ...
This paper presents the results of eight years of scientific research on the effect of polypropylene shelters (Tully tubes) and hydrophilic polymers on growth, survival, health and physiological condition of pedunculate oak seedlings (Quercus robur L.). The experiment was established in 2014 on relative forest soil, on partially forested land in subcompartment 35a, forest management unit Kragujna, which is managed by the Forest Administration Vinkovci, Forest Office Županja. In the autumn of 2014, one-year-old bare-rooted pedunculate oak seedlings were planted as a randomized block design experiment - four blocks with four repetitions. Four types of planting were tested: seedlings without a polypropylene shelter, without the addition of Zeba hydrophilic polymer granules (S variant), seedlings without a polypropylene shelter, with the addition of Zeba hydrophilic polymer granules (SP variant), seedlings with a polypropylene shelter, without the addition of Zeba hydrophilic polymer granules (SS variant), and seedlings with a polypropylene shelter, with the addition of Zeba hydrophilic polymer granules (SSP variant). The experiment was established as a result of considering the long-term problem of difficulties in natural regeneration. Disturbances in natural regeneration are certainly caused by increasing climate changes (floods, long-term droughts, storms, hailstorms, etc.) and other unfavourable biotic and abiotic factors that cause a significant reduction in quantities and/or an almost complete absence of pedunculate oak acorn yield. Due to the aforementioned circumstances, in the very near future we will be forced to resort more often to different forms of artificial forest regeneration, such as regeneration by planting sheltered seedlings that are less exposed to risks and challenges during survival, and which have greater competitiveness in relation to other vegetation on the regeneration surface (higher growth). Nowadays, this method of regeneration is used mostly for filling in places where, for various reasons, natural regeneration has been unsuccessful on several occasions and over a long period of time, and/or where there are great difficulties in carrying out natural regeneration (floods, areas damaged by fires, game damages and competition of weeds). This paper presents the results of scientific research after five periodic measurements, i.e. after the first, second, fifth, sixth and eighth growing season. The results show that even after the eighth growing season, seedlings protected with a polypropylene shelter have greater survival rate and greater height growth than unprotected seedlings. The highest survival rate was found in seedlings protected with a polypropylene shelter, with the addition of Zeba hydrophilic polymer of 82.14% (SSP variant), while unprotected seedlings with the addition of Zeba hydrophilic polymer (SP variant) had the lowest survival rate of 62.63%. The highest growth was recorded on seedlings protected with a polypropylene shelter, with the addition of Zeba hydrophilic polymer (SSP variant) amounting to 202.75 cm, while on average the smallest seedlings were those without polypropylene shelter protection and without the addition of Zeba hydrophilic polymer (S variant), amounting to 129.02 cm.
... Biochemically, submergence stress causes hypoxia, ethylene formation, and a shift toward anaerobic metabolism. Anatomically, it induces the formation of the aerenchyma lacunae (Sullivan & Eastin, 1975;Myers, 1988;Maimaitiyiming et al., 2017). Furthermore, flooding promotes the development of adventitious roots, induction of a new root system, and re-orientation of the root system (Posso et al., 2020;Zhou et al., 2020;Samanta et al., 2021). ...
... Biochemically, submergence stress causes hypoxia, ethylene formation, and a shift toward anaerobic metabolism. Anatomically, it induces the formation of the aerenchyma lacunae (Sullivan & Eastin, 1975;Myers, 1988;Maimaitiyiming et al., 2017). Furthermore, flooding promotes the development of adventitious roots, induction of a new root system, and re-orientation of the root system (Posso et al., 2020;Zhou et al., 2020;Samanta et al., 2021). ...
... Biochemically, submergence stress causes hypoxia, ethylene formation, and a shift toward anaerobic metabolism. Anatomically, it induces the formation of the aerenchyma lacunae (Sullivan & Eastin, 1975;Myers, 1988;Maimaitiyiming et al., 2017). Furthermore, flooding promotes the development of adventitious roots, induction of a new root system, and re-orientation of the root system (Posso et al., 2020;Zhou et al., 2020;Samanta et al., 2021). ...
Water is essential for plant growth and development; however, an excessive and lower amount of water negatively affects crop productivity and survival. In natural ecosystems, flash floods may cause the complete submergence of plants in water, which results in the induction of multiple stress tolerance mechanisms. The conditions underwater and the reaction of plants to these conditions are low oxygen, low light, and nutrient deficiency come under the former category of drought stress and are conditions that the plant faces underwater. Production of endogenous hormones and activation of signaling molecules of the glutamate family are the plant responses to the above stress conditions. A high risk of infection is a consequence of being immersed in water. In this study, we aimed to explore soybean's tolerance mechanisms and acclimatization responses to partial and complete submergence and drought at the physiological and molecular levels, which will provide insights into the regulatory networks eliciting tolerance during water stress. The results suggested that upon exposure to the osmotic stress, there is an increase in the concentration of histidine, arginine, proline, and glutamate contents in the complete submergence and drought stress group as compared to the control group. Moreover, the results also suggested that the SA level increases in its 12 hours and then decreases in the next 120 hours. Interestingly the regulation of ABA is the opposite. It increases as it increases with time. An increased width leaf was observed in all study groups except the control group.
... Biochemically, submergence stress causes hypoxia, ethylene formation, and a shift toward anaerobic metabolism. Anatomically, it induces the formation of the aerenchyma lacunae (Sullivan & Eastin, 1975;Myers, 1988;Maimaitiyiming et al., 2017). Furthermore, flooding promotes the development of adventitious roots, induction of a new root system, and re-orientation of the root system (Posso et al., 2020;Zhou et al., 2020;Samanta et al., 2021). ...
... Plant water status was evaluated periodically by midday shoot water potential (ΨMD) and relative water content (RWC) on three olive trees per treatment, every two weeks, according the methodology reported in previous studies (Marques et al., 2021;Fernandes-Silva et al., 2016). Water stress integral (WSI) was evaluated as defined by Myers (1988) and described in Fernandes-Silva et al. (2013b). ...
Deficit irrigation strategies are one of the chief alternatives to cope with water shortages in the actual context of climate change. Regulated (RDI) and sustained deficit irrigation (SDI) are the main deficit irrigation strategies that have been adopted in irrigated olive orchards. The success of the RDI depends on the exact period to impose the water deficit. The objective of this work was to evaluate and compare the effect of different strategies of RDI and SDI on fruit growth and oil accumulation on ‘Cobrançosa’, during the 2019 and 2020 seasons, in an olive orchard located at the northeast of Portugal. Two sustained deficit irrigation were tested, with 60 and 30% (SDI30) of control (FI) plus two RDI, one irrigated as the control (FI) except in the pit hardening (PI) period (reduced to 10% of FI), and the other the irrigation cut-off in this phenological stage, after that was irrigated equally to SDI60. A good relationship was observed between oil concentration (r2=0.89; p<0.01) and the total water stress integral, which was evaluated by midday shoot water potential. Oil concentration in the fruits varied between 32.4 and 32.9% (SDI30) to 43.1-47.9%(FI). Oil concentration and yield of RDI100 was not statistically different to the control. Moreover, oil content fruit-1 (mg oil/fruit dry weight) was affected by water stress except in RDI100 treatment. Olive oil obtained from the most stressed treatment were the richest in minor compounds, like vitamin E and polyphenols derivates of secoiridoids (hydrolyzed hidroxitirosol and tyrosol). Results from 2020 harvest indicated that all the oil from olives subjected to deficit irrigation treatments and from the control met the health claim on polyphenols. The RDI strategies had a positive effect over the two SDI strategies, especially the RDI100, as it increased oil yield nearly to double in relation of SDI60 and more than double to the SDI30. Also, The SDI60 treatment had a very positive effect over SDI deficit irrigation strategies. In conclusion, RDI100 seems to be a good DI to implement on ‘Cobrançosa’ in this region. For a better performance of the RDI60, it seems that to supress irrigation on pit hardening period should be replaced by reducing the volume of applied water to 10-20% of FI, namely in soils with low water storage capacity.
... To differentiate the irrigation scenarios in terms of water stress intensity, the water stress integral indicator WS Ψ (Myers, 1988) was used: ...
... In addition, the additive effect of water deficit duration and intensity was accounted for by the water stress integral (S Y ) computed as the sum of Y stem measured every day during a given period (Myers, 1988). It was calculated from the Y stem values over the veraison to harvest periods, subtracting those with the least negative value registered in a fully irrigated vineyard by Buesa et al. (2017) (−0.24 ...
Under semiarid and warm climates, field practices for climate change adaptation have to be defined in order to modulate grape composition according to the desired wine styles. Under this context, the present study investigated several viticulture practices in cv. Macabeo for Cava production. The experiment was carried out over 3 years in a commercial vineyard located in the province of Valencia (eastern Spain). The techniques tested were (i) vine shading, (ii) double pruning (bud forcing), and (iii) the combined application of soil organic mulching and shading, all of them tested against a control. Double pruning significantly modified phenology and grape composition, improving the wine alcohol-to-acidity ratio and reducing the pH. Similar results were also achieved by shading. However, the shading strategy did not significantly affect yield, unlike double pruning, which reduced vine yield even in the year following its application. Shading alone or in combination with mulching significantly improved the vine water status, suggesting that these techniques can also be used to alleviate water stress. Particularly, we found that the effect of soil organic mulching and canopy shading on stem water potential was additive. Indeed, all the techniques tested were useful for improving wine composition for cava production, but double pruning is only recommended for premium Cava production.
... We hypothesize that this behaviour is related with the strong relationship found between Ψ trunk and VPD (reference equations are included in the supplementary material), so decreases in VPD during the afternoon cause Ψ trunk drops. Consequently, the calculation of water stress indicators such as the water stress integral (Myers, 1988) might result affected if Ψ trunk is used instead of Ψ stem . Pagay (2022) reported that under environmental conditions with high evaporative demand, the relationship between both indicators weakened. ...
Microtensiometers are plant-based sensors than can continuously measure trunk water potential (Ψtrunk). This new water status indicator, Ψtrunk, was compared with the midday stem water potential (Ψstem) measured with a pressure chamber, the current standard for assessing water status in trees, leaf water potential, and maximum daily shrinkage (MDS) in adult 'D'Anjou' pear trees (Pyrus communis L.) irrigated following two strategies, (1) a control treatment (CTL) irrigated at 100% of crop evapotranspiration and, (2) regulated deficit irrigation (RDI). Ψtrunk, Ψstem and MDS were directly influenced by soil water content and atmospheric demand. MDS was able to detect water stress in DI trees the earliest. However, variability was high and it was not sensitive enough to detect significant differences between irrigation treatments at the end of the season. MDS had a maximum value of 300 µm (Ψstem =−1.4 MPa). On the other hand, variation for midday Ψstem and Ψtrunk was low and both indicators were able to distinguish between irrigation strategies. Midday Ψstem and Ψtrunk had a strong linear relationship similar to the identity line (R2 = 0.88). However, when Ψstem and Ψtrunk were compared in the afternoon, Ψtrunk reported by microtensiometers was − 0.7 MPa lower than Ψstem measured by a pressure chamber. The daily relationship between trunk diameter variations and Ψtrunk measured with the microtensiometers followed five different stages. Changes in trunk diameter were delayed relative to changes in Ψtrunk. The seasonal relationship between the MDS and Ψtrunk was strongly related at the start of deficit irrigation (R2 = 0.63), but when the complete season was considered, this relationship was weaker (R2 = 0.44). Moreover, the low coefficient of variation and high sensitivity of the midday Ψtrunk measured with the microtensiometers supports the suitability of using them in automated irrigation systems to monitor tree water status in spite of their high dependence on environmental conditions. This is one of the first studies that validates the use of microtensiometers to continuously monitor tree water status in fruit trees across two consecutive seasons under differing irrigation treatments.
... Therefore, the first measurement was normalized to 48 days after budburst (DABB), which was the earliest measurement taken in the whole trial (in 2020). IntΨ was calculated following the equation defined by Myers (1988) (1): ...
Elevated temperatures during berry ripening are detrimental to grape quality. The crop forcing technique (summer pruning that ‘forces’ the vine to start a new cycle) increases must acidity and malic acid concentration at harvest by delaying the date of veraison. However, little information is available on the sensitivity to water stress of forced vines. A 3-year trial was conducted to test three irrigation strategies in forced vines: a minimum threshold of mid-day stem water potential (Ψs) of −0.75 MPa before forcing (DI), a minimum Ψs threshold of −1.2 MPa only after veraison (RDI), and the combination of both treatments (DI + RDI). Results were compared to a non-forced treatment with a minimum Ψs threshold of −1.2 MPa after veraison (C-RDI). Must acidity increased, and pH decreased in the forced treatments. However, yield was reduced by 35% and irrigation requirements increased by 20% when comparing forced and unforced treatments. As a result, water use efficiency was reduced in forced treatments. Only after a dry spring did the, DI (11%) and DI + RDI (30%) treatments, save water compared to the C-RDI treatment. Moreover, although Ψs before forcing never fell below −0.75 MPa, a significant negative correlation (R² = 0.76) was found between the integral of water stress before the vines were forced and the number of forced bunches per vine. Post-veraison water stress in forced vines reduced the polyphenol content of the wine. Our findings suggest that forced vines are extremely sensitive to even mild water stress.
... Vine water status was determined through Y stem measured on five vines per treatments, at 7-10-day intervals from the irrigation differentiation until harvest (13 times in both years) by a Scholander pressure chamber (PMS Instruments, Albany, OR, USA) following the protocol reported in Palai et al. (2021). The water stress integral (WSI) was then calculated from Y stem data, as reported in Myers (1988), and the daily WSI (dWSI) was determined from berry pea size to lag phase (PS-L), from lag-phase to the beginning of veraison (L-V), from the beginning of veraison to harvest (V-H), and from pea-size to harvest (PS-H). ...
The impact of water deficit on volatile organic compounds (VOCs) responsible for grape aroma remains quite unclear. The aim of this study was to evaluate the effect of different timing and intensity of water deficit on berry VOCs and on their biosynthetic pathways. Fully irrigated control vines were compared with the following treatments: i) two different levels of water deficit from berry pea-size through veraison, ii) one level of water deficit during the lag-phase, and iii) two different levels of water deficit from veraison through harvest. At harvest, total VOC concentrations were higher in berries of water stressed vines from berry pea size through veraison or during the lag phase, whereas post-veraison water deficit determined similar concentrations as control. This pattern was even more pronounced for the glycosylated fraction and was also observed for single compounds, mainly monoterpenes and C13-norisoprenoids. On the other hand, free VOCs were higher in berries from lag phase or post-veraison stressed vines. The significant glycosylated and free VOCs increment measured after the short water stress limited to the lag phase highlight the pivotal role played by this stage in berry aroma compound biosynthesis modulation. The severity of water stress before veraison was also important, since glycosylated VOCs showed a positive correlation with the pre-veraison daily water stress integral. The RNA-seq analysis showed a wide regulation induced by irrigation regimes on terpenes and carotenoids biosynthetic pathways. The terpene synthases and glycosyltransferases as well as genes of the network of transcription factors were upregulated, especially in berries from pre-veraison stressed vines. Since the timing and intensity of water deficit contribute to regulate berry VOCs, irrigation management can be used to achieve high-quality grapes while saving water.
... However, in more humid and variable climates, measurement on one day may not represent the stress on other days. A simple integration of periodic measurements of water potential have been used to attempt to address this (Myers, 1988). A study of potential integrals and grapevine performance in Chile found the best correlations to berry soluble solids (R 2 =0.7), but lower correlations to berry numbers or weight (Zúñiga et al., 2017). ...
... In fact, 2019 was the only season in which Ψ s , which is a very robust indicator to discriminate different vine water status independently of the environment (Santesteban et al., 2019), was clearly affected by the irrigation regime in DI and DI + RDI compared to C-RDI and RDI treatments (Fig. 2). However, when analysing pre-forcing IntΨ, which is an appropriate tool to indicate the cumulative stress (Myers, 1988), it was evident that DI and DI + RDI treatments were more stressed than RDI (Table 3). ...
Elevated temperatures during berry ripening are detrimental to grape quality. The crop forcing technique (summer pruning
that ‘forces’ the vine to start a new cycle) increases must acidity and malic acid concentration at harvest by delaying the
date of veraison. However, little information is available on the sensitivity to water stress of forced vines. A 3-year trial was
conducted to test three irrigation strategies in forced vines: a minimum threshold of mid-day stem water potential (Ψs) of
−0.75 MPa before forcing (DI), a minimum Ψs threshold of −1.2 MPa only after veraison (RDI), and the combination of
both treatments (DI + RDI). Results were compared to a non-forced treatment with a minimum Ψs threshold of −1.2 MPa
after veraison (C-RDI). Must acidity increased, and pH decreased in the forced treatments. However, yield was reduced by
35% and irrigation requirements increased by 20% when comparing forced and unforced treatments. As a result, water use
efficiency was reduced in forced treatments. Only after a dry spring did the, DI (11%) and DI + RDI (30%) treatments, save
water compared to the C-RDI treatment. Moreover, although Ψs before forcing never fell below −0.75 MPa, a significant
negative correlation (R2 = 0.76) was found between the integral of water stress before the vines were forced and the number
of forced bunches per vine. Post-veraison water stress in forced vines reduced the polyphenol content of the wine. Our findings
suggest that forced vines are extremely sensitive to even mild water stress.
... Ψ stem was measured on the same trees used for the leaf gas exchange measurements at midday (around 12:00 solar time) using a pressure chamber (model 3000, Soil Moisture Equipment Corp., Goleta, CA, USA) and following the recommendations of Hsiao [74], in leaves from the north side of the trees and close to the tree trunk that were bagged with foil-covered aluminum envelopes at least 2 h before the measurements to limit transpiration [75]. The water stress integral (SΨ stem ) was calculated from the equation defined by Myers [76]: ...
The aim of this study was to test the combined effect of water stress and cropping system on yield and fruit quality in Bearss lime trees. For this purpose, two irrigation treatments were applied during stage II of fruit growth: control (well irrigated, automatically managed by soil water content sensors) and stress (non-irrigated), both under open-field and shaded conditions. Soil water status was assessed by determining soil water content and plant water status by measuring stem water potential (Ψstem), stomatal conductance (gs), and net photosynthesis (Pn). Yield parameters (kg and the number of fruits per tree and fresh mass per fruit) and fruit quality were assessed on two harvest dates. In addition, on the second harvest date, the content of metabolites and nutrients in the lime juice was analyzed. The results showed that soil water deficit induced 35% lower gs values in open-field than in shaded conditions. The highest kg and the number of fruits per tree were observed in the shaded system, especially on the first harvest date. The lowest yield was observed in stressed trees grown without netting. Slightly higher fresh mass and equatorial diameter were observed in shaded fruits than in open-field fruit. Soil water deficit increased fruit total soluble solids and decreased juice content, especially in open-field trees. Shaded conditions made the lime trees more resilient to soil water deficit, which led to higher yields and better external fruit quality traits. In addition, fruit precocity was significantly higher in the shaded system.
... The mid-day (11:00-13:00 h) leaf water potential (MLWP) and stem water potential (MSWP) were measured in two leaves per plant fortnightly using pressure chamber (PMS instrument, Oregon, USA) on cloudless day. The water stress integral (S ψ ) was determined using the mid-day leaf and stem water potentials, according to the equation defined by Myers (1988): ...
Water scarcity is a major constraint to citrus production in tropical regions. Proper irrigation scheduling using efficient irrigation methods such as microirrigation systems is a key to sustainable citriculture. In recent years, plant-based measurements have emerged as potential methods for irrigation management in crops. Infrared thermometry (IT) is one of the modern tools to monitor plant water stress. Crop water stress index (CWSI) computed using plant foliage temperature measured by IT has been considered as a potential index for irrigation scheduling. The present study was conducted to evaluate the effects of CWSI-based drip irrigation scheduling on water use, plant water status, fruit yield and quality and water productivity of citrus in central India. Differential irrigation was scheduled at CWSI of 0.6, 0.4 and 0.2 in combination with 40% crop evapotranspiration (ETc), 60% ETc and 80% ETc, respectively, and compared with alternate day full irrigation (FI, 100% ET) using drip irrigation system. The fruit yield in irrigation at CWSI 0.4 + 60% ETc was at par with that at CWSI 0.2 + 80% ETc and FI. However, 40% water saving resulted in 74% higher water productivity in irrigation at CWSI 0.4 + 60% ETc compared with FI. The fruits under CWSI 0.4 + 60% ETc had superior qualities (high fruit weight, total soluble solids and lower acidity) than FI fruits. Plant canopy volume (PCV) was highly correlated (R2 = 0.89) with crop water use. Overall, the study reveals that irrigation at CWSI 0.4 + 60% ETc could improve the water productivity and fruit quality with substantial water saving in citrus production in water scarce region.
... year conditions for context. Wet-year conditions were determined for the 2 years with the least negative predawn leaf water potential integrals, that is, water stress integrals (Myers, 1988). ...
Soil and atmospheric droughts increasingly threaten plant survival and productivity around the world. Yet conceptual gaps constrain our ability to predict ecosystem scale drought impacts under climate change. Here, we introduce the ecosystem wilting point (ΨEWP), a property that integrates the drought response of an ecosystem's plant community across the soil‐plant‐atmosphere continuum. Specifically, ΨEWP defines a threshold below which the capacity of the root system to extract soil water and the ability of the leaves to maintain stomatal function are strongly diminished. We combined ecosystem flux and leaf water potential measurements to derive the ΨEWP of a Quercus‐Carya forest from an “ecosystem pressure‐volume (PV) curve”, which is analogous to the tissue‐level technique. When community predawn leaf water potential (Ψpd) was above ΨEWP (= −2.0 MPa), the forest was highly responsive to environmental dynamics. When Ψpd fell below ΨEWP, the forest became insensitive to environmental variation, and was a net source of carbon dioxide for nearly two months. Thus, ΨEWP is a threshold defining marked shifts in ecosystem functional state. Though there was rainfall‐induced recovery of ecosystem gas exchange following soaking rains, a legacy of structural and physiological damage inhibited canopy photosynthetic capacity. Although over 16 growing seasons, only 10% of Ψpd observations fell below ΨEWP, the forest is commonly only 2–4 weeks of intense drought away from reaching ΨEWP, and thus highly reliant on frequent rainfall to replenish the soil water supply. We propose, based on a bottom‐up analysis of root density and soil moisture characteristic curves, that soil water acquisition capacity is the major determinant of ΨEWP, and species in an ecosystem require compatible leaf‐level traits such as turgor loss point, so that leaf wilting is coordinated with the inability to extract further water from the soil.
... Leaf water potential was measured at mid-day in fully expanded leaves in the sun using a Scholander pressure chamber (model 1000, PMS, Albany, OR, USA) technique [24] in every treatment replicate. The Stress Integral (SI) was calculated from leaf water potential data according to [25]: ...
Common bean is typically cultivated in the Mediterranean basin, an area where water scarcity could limit yield. This species has a broad range of food uses (seed or pod) and very diverse growth patterns (indeterminate or determinate), which hinders any deficit irrigation strategy. The aim of this work was to evaluate the response of the vegetative and reproductive growth stages to water stress in beans of indeterminate habit. During two consecutive Autumn seasons (2020 and 2021), two cultivars of green bean were grown in a greenhouse in Seville (Spain). The experimental design was a split plot with four replications. One of the factors considered was the cultivars Helda, and Perfección Blanca; and the other was the irrigation strategy: a control treatment, which received 100% of crop evapotranspiration, and a regulated deficit irrigation (RDI) treatment, with 30% of the water applied to the control. In both seasons, significant differences were found between cultivars, but irrigation only reduced branch development around 50%. Reproductive growth was not markedly affected, although a clear diminishing trend of approximately 25% was measured in P. Pod length and the number of non-commercial pods were not importantly impacted by irrigation in any of the cultivars. Moderate water stress conditions did not reduce the quality and quantity of the yield. Therefore, the current irrigation strategy could increase water savings with low or no yield reduction.
... where Ψs is the average of midday stem water potential between two consecutive measurement dates, c is the maximum Ψs measured during the season, and n is the number of days between measurements dates (Myers, 1988). ...
Changes in rainfall patterns and increases in ambient air temperature (i.e., warming) are expected with climate change. Yet, little information is available on how plant water status will respond to the combination of water deficit and increased air temperature in fruit tree species. The objective of this study was to evaluate the individual responses of deficit irrigation and warming and their combination on plant water status during the late winter and spring in young olive trees. Two temperature and two irrigation levels were applied in open top chambers during the late winter and spring of 2018 and 2019 to two- or three-year-old, potted trees (cv. Arbequina in 2018; Coratina in 2019). The temperature levels were a near-ambient control and a warming treatment that was 4 °C above the control, while the two irrigation levels were 100% and 50% of irrigation needs. Midday stem water potential (Ψs), stomatal conductance, net leaf photosynthesis, transpiration, and leaf temperature were measured periodically, and the difference between leaf and air temperature (ΔT) was calculated. The Ψs generally decreased due to irrigation deficit and warming when applied individually. When both treatments were combined, an additive response was observed. In contrast, stomatal conductance and net photosynthesis were consistently decreased by deficit irrigation, but were less affected by warming. Irrigation deficit did not affect leaf temperature under our experimental conditions. As was expected, warming most often increased leaf temperature, but it also significantly decreased ΔT early in the season when leaf transpiration appeared to be greater due to warming. The results indicate that modifications in water management with global warming will likely be required given the mostly negative individual or additive effects of irrigation deficit and air temperature on Ψs and other variables.
... One leaf per tree, healthy and close to the trunk, was taken from four trees per treatment and per block; leaves were previously wrapped in foil-covered bags at least 2 h before measurement. The additive effect of water deficit duration and intensity was accounted for by the water stress integral (S Ψ ) computed as the sum of plant water potential measured every day during a given period [44]. It was calculated from the Ψ s values across the season subtracting the least negative Ψ s value registered in a fully irrigated almond orchard by Egea et al. [45] and multiplying it by the number of days of the computed period. ...
The sustainability of woody crop agroecosystems requires continued improvements to water, nutrient and soil management. In this work, the combination of resource availability or fertigation dose with soil management practices was tested in a 2 × 2 factorial design in a drip irrigated young almond orchard. The fertigation doses were: the farmer supply at 60% of crop evapotranspiration and full nutrient requirements and the half-farmer supply at 30% of crop evapotranspiration and half nutrient requirements. The soil management practices were: bare soil and cover crops in the inter-row (mixture of grasses and legumes). Tree growth, yield, water and nutrient status, and cover crop biomass and nutrient status were determined, as well as inter-row soil C and N concentration. Results showed that the effect of resource availability was independent of soil management and vice versa. The half farmer treatment reduced tree vegetative growth and yield compared to farmer treatment, due to a negative effect on the water status, without observing a decrease in the concentration of nutrients in leaves or fruit. Trees with cover crop also reduced growth and yield compared to bare soil management. This was due to a nutritional competition, mainly of Ca, Fe, Mn and Zn, rather than to a decline in tree water status. Cover crops sequester up to 1 t/ha/year of carbon but do not increase soil organic carbon, nor soil total nitrogen. Cover crops proved to be efficient in reducing soil nitrate concentration in the topsoil and therefore has potential to prevent its leaching. Deficit fertigation and the use of cover crops can be effective practices to preserve and save water and nutrient resources in Mediterranean agroecosystems, but should be established with caution so as not to compromise the profitability of the orchard.
... Me urements were made weekly and coincided with the end of each irrigation period (P conditioning, Stress 1, Stress 2, and Recovery) using a pressure chamber (Soil Moistu Equipment Corp. Model 3000, Santa Bárbara, CA, USA) on one leaf per tree and one t per replicate of each treatment (n = 4). For Ψstem, leaves were selected from the north part of the tree and close to the tree trunk and placed in plastic bags covered with alum The intensity of water stress endured by each treatment was calculated by the water stress integral (SΨ stem ), using the equation defined by Myers [41]: ...
This work studied the sensitivity of the postharvest period of early maturing nectarine trees (Prunus persica L. Batsch, cv. Flariba) to water stresses. Along with a well-irrigated treatment (T-0), three water deficit treatments (by withholding irrigation) were applied: T-1: early postharvest (June–July), T-2: late postharvest (August–September), and T-3: the whole postharvest period (June–September). Soil water content (θv) and midday stem water potential (Ψstem) were measured throughout the study. During winter dormancy, L-arginine, starch, and phosphorus content in the roots were analyzed. Yield, fruit quality, and metabolites were determined at harvest. Ψstem reached −1.7 and −2.3 MPa at the end of the early and late postharvest periods, respectively. Total yield and number of fruits per tree were significantly reduced in all deficit treatments with respect to T-0, while no significant differences were observed in physicochemical fruit quality. The T-2 treatment showed the highest percentage of cracked fruits. Significantly, lower values of L-arginine and phosphorus were observed in the roots of T-2 trees, with respect to T-0, while they were similar in T-1 trees. Although the early postharvest stage is key for the application of RDI strategies, our results indicated that the late postharvest period was also a sensitive period to severe drought, as the accumulation of winter root reserves (L-arginine and phosphorus) was reduced, which limited yield.
... The leaves used for these measurements were enclosed in hermetic plastic bags and covered with aluminium foil for at least 1 h prior to measurement (Choné et al. 2001). The water stress integral (S Ψ ) was calculated using the equation proposed by Myers (1988). ...
Warm and semi-arid climates are characterized by rainfall scarcity, resulting in the frequent use of low-quality water for irrigation. This work was undertaken to study the effects of water stress and saline irrigation on yield and grape composition of Monastrell grapevines grafted onto 1103P rootstock. The experiment was carried out during three consecutive seasons in a commercial vineyard located in Jumilla (SE Spain) with a loamy-sandy soil. Rainfed vines were compared with five watering regimes including a Control, irrigated with standard water, and four treatments that combined two different schedules for irrigation initiation (pre- and post-veraison) with saline water obtained by adding two types of salts (sulphates and chlorides). Vines from treatments with more severe water stress (i.e., rainfed) showed lower yields and vegetative growth. Moreover, the Rainfed treatment clearly modified grape composition when compared with the Control treatment by increasing berry phenolic content. The application of saline water slightly affected vine performance and grape composition regardless of the type of salts added to the irrigation water. Indeed, the watering regime had a greater effect on yield, vegetative growth and grape composition than the use of different saline waters. Our results suggest that, in the mid-term (3 years), and with a vineyard soil with good drainage, the use of saline waters is not detrimental to vine performance, but does not improve grape composition. Further research is required to assess the long-term effects of saline water application, particularly in view of the important accumulation of chlorides and sodium in leaf tissues observed in vines watered with salty water at the last season of this experiment.
... The SWP was measured at 7-10 day intervals with a Scholander pressure chamber using standard protocols (Palai et al. 2021). The water stress integral (WSI) was calculated from the SWP values as reported by Myers (1988). ...
Background and Aims: Water deficit modifies the concentration of the aroma compounds of grape berries, but little information is available on the effect of deficits applied at different phenological stages. We evaluated the effect of deficit irrigation on glycosylated volatile organic compounds (VOCs) responsible for the aroma of berries of Sangiovese and Merlot cultivars grafted on 1103P or SO4 rootstocks. Methods and Results: Vines were subjected to either pre-or post-veraison water stress, and berry composition compared against that of fruit of fully irrigated vines. At harvest, a higher concentration of glycosylated VOCs was measured in berries from vines stressed pre-veraison, but while it increased as water deficit increased in Sangiovese, this occurred only at a low or moderate level of stress in Merlot. Post-veraison water stress had a negative or negligible effect on the concentration of glycosylated VOCs in berries at harvest. The rootstock affected the concentration of glycosylated VOCs, particularly in vines stressed pre-veraison, with higher glycosylated VOCs observed for SO4 grafted vines than for 1103P grafted vines. Conclusions: Pre-veraison water deficit enhanced the concentration of berry glycosylated VOCs, while post-veraison deficit did not. The rootstock-scion interaction might amplify the irrigation effect on berry glycosylated VOCs. Significance of the Study: Modifying the timing and volume of irrigation might allow management of berry flavour for improved fruit and wine composition. Irrigation protocols should be tailored for specific cultivar-rootstock combinations.
... Then, leaves were cut and immediately placed in the chamber. Moreover, to describe the accumulated effect of the deficit irrigation treatments between rootstocks, the water stress integral (SI ) was calculated as follows (Myers, 1988): ...
Climate change effects are unbalanced in all regions and cultivars linked to the wine industry. However, the impact of extreme weather events, such as drought and rising global temperatures, highlight the potential vulnerability in plant productivity, phenology, and crop water requirements that affect quality and harvests. Among adaptative measures for grapevine cultivars in existing or new winegrowing areas, the use of tolerant rootstocks to abiotic stress has been regarded as a mid-term strategy to face emerging constrains. The aim of this study was to compare naturalized or autochthonous rootstocks influence over grapevine cultivar performance and to characterize their response to deficit irrigation conditions. Data was collected from Cabernet Sauvignon and Syrah grafted plants for over 3 growing seasons (2018–2021) from a hyper-arid experimental field in Vicuña, Chile. Morpho-physiological parameters were determined throughout seasons and combinations where significant effects from rootstocks, irrigation treatment, and cultivar were observed over An and gs, thus modifying CO2 assimilation and intrinsic Water Use Efficiency (WUEi). Primary productivity and yield were also modified by rootstock depending upon cultivar hydric behavior. Interestingly, cluster and berry traits were unaffected despite how water productivity and integral water stress were modulated by rootstock. In both cultivars, it was observed that trait responses varied according to the irrigation conditions, rootstocks, and their respective interactions, thus highlighting a relative influence of the rootstocks in the processes of adaptation to the water deficit. Moreover, harvest date and acidity were modified by deficit irrigation treatment, and rootstocks did not modify phenological stages. Adaptation of grapevines to expected lower water availability might be improved by using suitable tolerant rootstocks, and maturity index can be modified through irrigation management.
Super-high density olive orchards may increase profitability for table olive producers. However, water needs and fruit damage could limit their viability. Deficit irrigation scheduling would reduce the amount of water required, but rehydration before harvest is extremely important. The aim of this work was to compare a typical deficit farm management model with a regulated deficit irrigation one based on the plant water status. The experiment was carried out during three seasons in a three years-old (4 × 1.5 m) commercial table olive orchard. In both irrigation scheduling plots, seasonal amount of applied water was similar. Irrigation treatments were: common farm management (CFM), an almost constant rate of irrigation, and Regulated deficit (RDI) based on midday shaded water potential. Vegetative measurements suggested that RDI increased the external surface of the hedge, and this was related with greater yield in this treatment. Significant differences were found in of fruit size at harvest in some seasons, with larger fruits in RDI compared to CFM. However, fruit damage occurred during mechanical harvest in both irrigation managements, despite the higher skin firmness in RDI, and shows the need to carry out postharvest treatments to improve the quality of the final product. Accurate control of the tree water status would allow optimizing the amount of water available for table olive orchards.
La disponibilidad de agua es uno de los principales factores que determinan el rendimiento del viñedo en muchas regiones productoras de uva, por lo que sus implicaciones han sido ampliamente estudiadas con anterioridad. Sin embargo, para una determinada cantidad de agua de riego, la frecuencia de aplicación, que interviene en el patrón de distribución del agua en el suelo, puede jugar un papel relevante, pero este factor ha sido escasamente estudiado. El objetivo de este trabajo fue evaluar los efectos agronómicos de dos frecuencias de riego (cada 3 y cada 7 días) en cuatro variedades tintas de vid en cuatro Comunidades Autónomas. El experimento se llevó a cabo durante el año 2021, en viñedos de las variedades Garnacha Tinta, Tempranillo, Syrah y Mencía, localizados en Badajoz, Valladolid, Albacete y Lugo respectivamente. Las frecuencias de aplicación de riego se evaluaron en condiciones de disponibilidad de agua de riego limitada (30% ETo). La aplicación de diferentes frecuencias de riego favoreció cambios en el estado hídrico de las cepas que afectaron levemente a algunos aspectos tanto del desarrollo vegetativo como de los componentes del rendimiento. No se observaron efectos de la frecuencia de riego en las características cualitativas de la cosecha. Dada la variabilidad en los resultados observados, ocasionada por las características edafoclimáticas y el factor varietal de cada localización, es necesario profundizar en el estudio a medio-largo plazo para determinar con claridad el efecto de la frecuencia de aplicación riego sobre el comportamiento de la vid.
When considering deficit irrigation, the most resistant period to water stress in olive crops is during the pit hardening. However, the determination of this period and the impact that water stress has on its onset or duration have not been clearly established. The aim of this work is to describe the impact of water stress on three processes that determine fruit development: fruit growth, endocarp hardening, and oil accumulation. This experiment was conducted between 2021 and 2022, in a plot with olive trees that were 3 years old at the beginning of the experiment. The young trees were of cv Manzanilla de Sevilla and were planted in a 4 × 1.5 m frame. The treatments were: Control, irrigated close to what is considered the optimum level in which the water status of the crop ensures the absence of water stress; RDI, with a moderate stress during the pit hardening stage; Rainfed and Traditional Rainfed. This latter was included only in 2022 using a 7 × 5 m frame. Traditional Rainfed was included to compare with Rainfed, these were similar in the maximum level of water stress but not in the duration. The fruit growth, oil accumulation, and endocarp hardness were measured for a period of 2 years. The hardness curves fit accurately established Period II which was the one with the fast hardness increases. The water potential was measured periodically on leaves at midday, whereby the minimum and average potential and the stress integral were obtained for each of the periods indicated before using pit hardness measurements. The results suggest that endocarp hardening was the process most resistant to water stress, as it showed very little variation from the seasonal pattern, despite the high levels of stress achieved. The fruit growth process was the most sensitive to water stress, but the recovery was fast in conditions of moderate water stress level. The oil accumulation started slowly during Period II, but its rate increased at the end of the period. This later process was moderately resistant to water stress. However, although the accumulation rate was faster during Period III, it was influenced by the water status during Period II. Cumulative water stress was related with fruit growth and oil accumulation processes. Endocarp development could be useful for determining a/the deficit irrigation period because of its almost constant pattern. These periods would permit water management optimization according to final use of the fruit (oil or table). However, continuous monitoring of water stress would be needed.
Climate scenarios in the medium and long term (2010-2070) foresee increased summer rainfall for Uruguay and the region, with increased water deficits and excess episodes. Although at the international level irrigation in viticulture has a long experience and tradition, at the local level (Uruguay), only 10% of the vineyard surface area implements a fixed or complementary system for water supply in their crops. This work aimed to model the crop water requirements for a vineyard in southern Uruguay based on pedo-climatic variables. In addition, the plant response to controlled deficit irrigation was evaluated in two consecutive seasons. The experiment was conducted in a 1.1 ha commercial vineyard in Canelones, Uruguay (34°36'S, 56°14W), during two successive seasons (2020-2021). The additional irrigation (I) treatment was compared against a control (C) without irrigation. A controlled water deficit was established from flowering to harvest. The adjustment in the demand was made as a function of a percentage of crop evapotranspiration. The Kc of the crop was estimated using digital tools. The simulation of the water balance made it possible to evaluate the vineyard water needs. Plants subjected to controlled deficit irrigation showed higher vegetative growth, positively impacting yield and the accumulation of sugars and anthocyanins in the berry. Based on our results, a supplementary water supply, at the right doses and time, allows us to face water deficit situations, positively impacting the productive and economic variables. Knowing the variability in a vineyard is necessary to achieve proper irrigation scheduling and optimize water use. New technologies applied to irrigation are an opportunity for winegrowers to obtain more sustainable vineyards and production.
The efficient management of irrigation water can affect crop profitability quite significantly. The application of precision irrigation based on soil monitoring can help manage water resources. In viticulture, the irrigation technique is thought to strongly influence grape ripening and the final grape composition. In this study, an irrigation decision support system was compared to a surface drip irrigation system in a commercial vineyard located in Andrea (Southern Italy) planted with Vitis vinifera cv. Montepulciano. We aimed to investigate the ability of the DSS to save water while maintaining an acceptable yield and quality of the grapes. To allow for the comparison, eco-physiological as well as yield parameters were measured during the irrigation periods in both irrigation systems over two years (2019 and 2020). The results indicate that the vines grown using the DSS treatment were less stressed compared to the plants grown using farm irrigation in both years. The yield attributes showed slight or no significant differences between the treatments. The quality results showed no significant differences between the treatments in both years. Our results indicate that with savings of 10% and 17% of the irrigation water in the first and second year, respectively, the DSS was able to maintain good yield and quality levels as compared to the farm irrigation system. These two-year results provide a promising implementation of its use in precision irrigation.
In order to increase the crop water productivity (WPc) of the agricultural systems, and to support farmers in minimizing uncertainty of water availability, we conducted a three-years experiment in a commercial adult mandarin orchard to quantify the effect of sustained and severe deficit irrigation in combination with the use of geotextile mulch on the agronomic and physiological response of the crop. For this purpose, five treatments were tested: (i) a control (CTL) irrigated at 100% of the crop evapotranspiration (ET c) during the entire season; ii) sustained deficit irrigation (SDI), irrigated at ~70% of CTL; (iii) regulated deficit irrigation (RDI), irrigated as SDI, except during the initial period of the second fruit growth stage, when trees were irrigated at 35% of the CTL, maintaining a moderate water stress level of around -1.5 MPa of stem water potential (Ψs), until fruits reached 70% of their final size. In addition, two geotextile mulch treatments were established, using the same irrigation criteria as the SDI and RDI treatments. The available irrigation water supplied about 66% of the crop evapotranspiration, but if it is managed under a SDI regime with the incorporation of mulching it is possible to increase the crop sustainability and reduce the pressure over the water resources. Since SDI did not reduce the yield with respect to the CTL treatment, it increased WPc by 35% and the incorporation of mulch significantly increased the water status of the soil and the crop, thus reducing the intensity of water stress by 18% on average, which was expressed in a higher leaf gas exchange rate and was also a factor that significantly increased crop production variables and WPc .
Forstlicher Forschungsbericht München, Band 224; The project partners achieved the goal to describe the water balance within their respective site information mapping systems as realistically as possible, spatially highly resolved and dynamically in relation to climate change using deterministic water balance models. For this purpose, a universal parameterization of the hydrological model LWF-Brook90 was developed based on literature research and a comprehensive validation database with more than one million observed values from a total of 59 monitoring and experimental sites across Germany. This ensured the general transferability of the water balance model to the mapping units of forest site evaluation systems in Ger-
many. In order to keep the potential water consumption at the site independent of the stand stocking, standard stands were defined for Norway spruce (Picea abies (L.) H. Karst.), Scots pine (Pinus sylvestris L.), Douglas fir (Pseudotsuga menziesii (Mirbel) Franco), European beech (Fagus sylvatica L.) and Pedunculate and Sessile oak
(Quercus robur L., Qu. petraea (Mattuschka) Liebl.), which were applied to all sites. Thus, the largescale, methodologically uniform application of LWF-Brook90 allowed for a comparative assessment of hydrological conditions across sites.
Report is in German. Printed Version available: Förderverein Zentrum Wald Forst Holz Weihenstephan e.V.
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BACKGROUND
Climate change modifies the content and phenolic profiles of grapes and wines. It is known that high temperatures, related to climate change, reduce anthocyanins and procyanidin (catechin and tannin) compounds accumulated in the berries. In recent years, with the aim of improving the phenolic composition of the berries, the technique of crop forcing has been proposed to delay grape ripening to a more favourable period of temperatures.
RESULTS
In this study, crop forcing was applied to cv. Tempranillo vines on two different dates, after flowering (F1) and after fruit set (F2), and compared to a treatment control (NF, without forcing). Additionally, as a secondary factor, two irrigation strategies were established in each treatment: irrigation with no water stress, and a pre‐veraison deficit irrigation. The study was carried out in three consecutive years (2017–2019). For most of the parameters analysed, no interaction was found. Therefore, for these parameters, the effect of each of these techniques was investigated independently. Regardless of the irrigation strategy, F2 berries achieved higher contents of catechins and anthocyanins than NF berries. Each year, regardless of the irrigation strategy, crop forcing increased the content of monoglucoside forms, and had a positive effect on the total content of malvidin, petunidin, delphinidin, peonidin and malvidin derivatives, but only affected acetyl and coumaryl forms in 2017. However, the effect of irrigation strategy was less significant and consistent, being more dependent on the vintage.
CONCLUSION
Regardless of vine water status, crop forcing technique applied after fruit set could be used by vine growers to delay ripening of the grapes and thus achieve an increase in the anthocyanin characteristics of the grapes. © 2023 Society of Chemical Industry.
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