Sustained Deficit Irrigation Treatments Research Articles

Deficit irrigation strategies (PRD, SDI) and titanium nanoparticles improve water use efficiency and flower quality in greenhouse-grown cut roses

This study explored the use of deficit irrigation techniques for water management in the hydroponic greenhouse cultivation of cut roses. A factorial experiment was conducted using three irrigation treatments: full irrigation (FI), partial root drying (PRD), and sustained deficit irrigation (SDI), and three doses of titanium dioxide nanoparticle foliar application (0, 15, and 30 ppm) as stress alleviation. Results showed that drought stress increased biochemical parameters such as the plants' proline and total phenol content. Compared to SDI treatment, the PRD treatments have an increase in flower number by 40%. The PRD strategy has positive effects on drought tolerance by increasing osmotic and elastic adjustment. Therefore, higher relative water content and longer root length in PRD treatments were observed. Thus, Biomass water use efficiency significantly increased in PRD treatments compared to others. In the PRD treatment, yield WUE increases by 26% and 61% compared to FI and SDI, respectively. The results showed TiO2-NPs positively affected mitigating and even improving some traits in drought stress conditions. These results suggest the superiority of the PRD strategy, which improves growth characteristics and water use efficiency, leading to increased sustainability, reduced environmental impact of greenhouse toxic wastewater, and total profitability of the greenhouse.

Effect of deficit irrigation and mulching on the agronomic and physiological response of mandarin trees as strategies to cope with water scarcity in a semi-arid climate

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 (ETc) 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.

Biochemical properties of pomegranate (Punica granatum L.) juice as influenced by severe water stress

This research investigates the influence of two irrigation regimes on juice chemical and biochemical characteristics of eleven Mediterranean pomegranate (Punica granatum L.) cultivars during two consecutive years (2019–2020). Control trees were fully irrigated (FI) at 100% of crop evapotranspiration (ETc), and the stressed ones were subjected to a sustained deficit irrigation (SDI) of 50% ETc. Results showed that water stress effect on juice quality attributes significantly varied depending on genotype with divergent amplitude variations and patterns under each year. There were significant decreases in soluble solids content (TSS), titratable acidity and pH on 8 cultivars. Soluble sugars content showed a significant decrease in 5 cultivars, combined with a decrease in amino acids content (AAC) for 2 cultivars. The SDI treatment decreased phenolic compounds content in 8 cultivars, with an often significant effect on anthocyanins content, thereby reducing the antioxidant activity level. According to principal component analysis, variations in TSS and AAC were the most discriminating changes induced by water stress applied over all studied cultivars. Overall, this study showed that SDI often leads to produce pomegranate juice with lower quality. However, the significant genotypic differences herein revealed suggest to move forward with in-depth analyzes to select resilient genotypes to cope with the climate change, particularly in arid lands.

Pomegranate plasticity to water stress: attempt to understand interactions between cultivar, year and stress level

This work investigated the effects of sustained deficit irrigation (SDI) on yield components and fruit physico-biochemical proprieties of two pomegranate cultivars, ‘Sefri’ and ‘Wonderful’ 21 trees each, in Sais plain (northern Morocco) over two consecutive seasons (2018–2019). Irrigation treatments consisted of a control, irrigation applied to fully satisfy crop evapotranspiration (100% ETC), and two SDI treatments: 70% ETC (SDI70) and 50% ETC (SDI50). The effects of the SDI treatments differed between cultivars and years. During the first year, yield and fruit weight were significantly reduced in ‘Sefri’ under SDI50. The same effect was also observed in the second year under SDI70. In ‘Wonderful’, a significant decrease in yield occurred in the second year under both SDI regimes. Fruit juice content was reduced in both cultivars, particularly under SDI50, with no significant effect on fruit aril content and aril weight. As for juice chemical properties, it was observed a decrease in total soluble solids, especially under SDI50. Furthermore, a significant decrease in juice soluble sugars content was observed in the first year for both cultivars. Total polyphenols content has significantly diminished in the second year in both cultivars. Likewise, total anthocyanins level displayed the same pattern, particularly in ‘Wonderful’. The findings suggest that SDI decreases yield and fruit quality even under moderate regime of 70% ETC. These negative effects may be dramatic depending on pomegranate genotypes, as observed in ‘Sefri’, compared to Wonderful variety. The great impact on species behavior toward water stress was particularly driven by the irrigation treatment, of which the interaction with the cultivar factor had the higher impact on the model. As many areas of how sustained deficit irrigation impacts pomegranate tree resilience are still needed to be investigated further, this study is a first attempt to explore water management in pomegranate in the Mediterranean semiarid lands.

Response of Spring Wheat (Triticum aestivum) to Deficit Irrigation Management under the Semi-Arid Environment of Egypt: Field and Modeling Study

In many areas of the world, water shortages prevail and threaten food production. Deficit irrigation was commonly investigated in dry areas as a precious and sustainable production approach. Using the CropSyst model to simulate the effects of different deficit irrigation treatments could help draw conclusions and save time, effort, and money. Therefore, the aims of this research were (i) to calibrate and validate the CropSyst model for wheat under different sustained and phenological stage-based deficit irrigation treatments, (ii) to simulate the impacts of the latter treatments on limiting wheat yield reduction. Two field experiments were conducted in Nubaria (Egypt), representing an arid environment. They included seven irrigation treatments: (1) 100%, (2) 75%, or (3) 50% of crop evapotranspiration (ETc) during the whole crop cycle; (4) 50% ETc at tillering only, or (5) at booting only, or (6) at grain filling only, or (7) at both tillering and grain filling, with the replenishment of 100% ETc to the treatments (4) to (7) in the remaining phenological stages. The results revealed that phenological stage-based deficit irrigation of wheat resulted in lower yield reduction compared to sustained deficit irrigation treatments, with a 6% yield reduction when 50% ETc was applied at the booting stage. Wheat yield loss was reduced to 4 or 6% when 95 or 90% of ETc were applied, respectively. The CropSyst model accurately simulated wheat grain and total dry matter under deficit irrigation with low RMSE value. In conclusion, the CropSyst model can be reliably used for evaluating the strategy of planned deficit irrigation management in terms of wheat production under the arid environment.

Influence of Regulated Deficit Irrigation and Environmental Conditions on Reproductive Response of Sweet Cherry Trees.

The reproductive response of fifteen year old sweet cherry trees (Prunus avium L.) combination ‘Prime Giant’/SL64 under Mediterranean climate to deficit irrigation was studied in a commercial orchard in south-eastern Spain for four seasons. Three irrigation treatments were assayed: (i) control treatment, irrigated without restrictions at 110% of seasonal crop evapotranspiration; (ii) sustained deficit irrigation treatment, irrigated at 85% ETc during pre-harvest and post-harvest periods, and at 100% ETc during floral differentiation, and (iii) regulated deficit irrigation treatment, irrigated at 100% ETc during pre-harvest and floral differentiation and at 55% ETc during post-harvest. The duration and intensity of the phenological phases of sweet cherry trees, including cold accumulation, flowering, fruit set or fruit and vegetative growth, were assessed to ascertain whether the different irrigation strategies imposed affect the trees’ reproductive response (fruit yield, fruit size, leaf area, fruit physiological disturbances, and starch and soluble carbohydrates stock) in the same season or have a negative effect in the next season. Deficit irrigation did not advance, enhance or penalize flowering, fruit set or fruit growth. Neither did it diminish carbohydrate concentration in roots or cause an increase in the number of double fruits, which was more linked to high temperatures after harvest. However, deficit irrigation decreased vegetative growth and consequently the leaf area/fruit ratio, which, when it fell below 180 cm2 fruit−1, affected cherry size.

Quality Attributes and Fatty Acid, Volatile and Sensory Profiles of "Arbequina" hydroSOStainable Olive Oil.

The use of deficit irrigation techniques on olive orchards is the main trend aiming to optimize water savings while improving functional and sensory characteristics of oils from trees under deficit irrigation techniques. The brand hydroSOStainable has been defined for crops produced under water restriction conditions. HydroSOStainable olive oils obtained under two new regulated deficit irrigation and one sustained deficit irrigation treatments in “Arbequina” olive trees were evaluated by analyzing quality parameters, antioxidant activity, total phenol content, fatty acid profile, volatile compounds, and sensory descriptors. Results showed that some of these irrigation strategies improved the phenol content at “moderate” stress levels, slightly enriched the fatty acid profile (~3.5% increased oleic acid and simultaneously decreased saturated fatty acids), and increased some key volatile compounds and also several key sensory attributes. Therefore, hydroSOStainable olive oil may be more attractive to consumers as it is environmentally friendly, has a higher content of several bioactive compounds, and has improved sensory characteristics as compared to control (fully irrigated) oils.

Water Management of Irrigated Cabernet Sauvignon Grapevines in Semi-Arid Areas

The effect of four years of deficit irrigation on water savings, yield, crop load, plant growth, and juice composition was determined on Cabernet Sauvignon grapes grown on the Central Coast of California. The growing season was divided into three periods. The first was from budburst to fruit set, during which there was no irrigation. The second was from fruit set to three weeks post-fruit set, during which 75% of calculated crop water use (ETc) was applied for all treatments. The third began three weeks post-fruit set and continued to harvest, during which irrigation resumed whenever the leaf water potential (LWP) reached −1.2 MPa in one of three sustained deficit irrigation treatments equal to 25/35% (LOW), 50% (MED), and 75/65% (HIGH) of ETc. The sum of rainfall and irrigation applied during the growing season ranged from 91 to 196 mm, from 145 to 234 mm, and from 198 to 273 mm for the LOW, MED, and HIGH treatments, respectively. Total water use, including soil water during the growing season, ranged from 250 to 359 mm, 288 to 418 mm, and 313 to 378 mm for the LOW, MED, and HIGH treatments, respectively. Yield was linearly related to the sum of irrigation and rain and to the total available water (rain, irrigation, and stored soil water) during the growing season. Yield was consistently lower in the LOW treatment across all years than in the MED and HIGH treatments; while yields in the MED and HIGH treatments were not different. Average pruning weight and cane weight declined in all treatments over the four years of the study, as did average berry size. Berry and wine composition was not affected by irrigation treatment within a given year, but were different across years due to climate, irrigation schedules, and harvest dates. Our results illustrate potential applied water savings during the growing season with moderate deficit irrigation (i.e., MED), with minimal or no significant effect on fruit yield and juice composition, while severe reduction of applied water (i.e., LOW) led to loss of yield without changing juice composition and would not be considered economically sustainable.

Precipitation before bud break and irrigation affect the response of grapevine ‘Zinfandel’ yields and berry skin phenolic composition to training systems

A 3-year trial was conducted in the hot climate of central California to assess the effect of training systems, irrigation treatments and their integration on canopy architecture, yield and flavonoid composition of ‘Zinfandel’grapevine. Training systems were spur-pruned (SP, 22 two-node spurs; 44 buds), split-canopy cane-pruned (CP, six-canes with 8-nodes; 48 buds), and mechanically-pruned (MP, 100mm hedge; 116 buds). Irrigation treatments were; sustained deficit irrigation (SDI), receiving 80% of crop evapotranspiration (ETc) from bud-break to leaf fall; and regulated deficit irrigation (RDI) receiving 80%, 50%, and 80% of ETc between bud-break and fruit set, fruit set to veraison and veraison to leaf fall, respectively. The vineyard received 87%, 30% and 23% of the ten-year average of winter precipitation in years 2013, 2014 and 2015, respectively. In year 2013, combination of CP and RDI performed better based on yields and grape skin flavan-3-ols, flavonols and total tannin concentration. However, CP under SDI treatment yielded the greatest total anthocyanin concentration in 2013. In 2014 and 2015, combination of MP and SDI had the greatest yield and anthocyanin concentration whereas MP under RDI tended to produce higher concentration of flavan-3-ol monomers, total flavonols and total tannins. Yields and grape composition were improved by high water availability. In lower precipitation years, yields and grape composition were ameliorated by MP. The regulated deficit irrigation treatment did not consistently improve grape composition in an arid region. The study provides information to identify combinations of training systems and irrigation treatments that can optimize reproductive and vegetative development while maintaining commercially acceptable flavonol, flavan-3-ol monomers and anthocyanin concentration in berry skin in a hot and arid climate.

Effect of deficit irrigation on vine performance and grape composition ofVitis viniferaL. cv. Muscat of Alexandria

Background and Aims Previous research has investigated widely the effects of irrigation application in red winegrape cultivars; however, white grape cultivars have been the subject of a lesser number of field trials. An experiment was undertaken for three seasons in a drip-irrigated, cv. Muscat of Alexandria/161-49C vineyard to define the most sustainable irrigation strategy for white winegrapes in eastern Spain. Methods and Results The treatments were as follows: (i) Control, irrigated at 100% of estimated crop evapotranspiration (ETc) for the entire season; (ii) sustained deficit irrigation (SDI), irrigated at 50% of Control; (iii) early deficit (ED), where pre-veraison irrigation was withheld, followed by 100% ETc; and (iv) late deficit (LD), irrigated as for the Control until veraison and thereafter at 25% ETc until harvest. Yield in ED and LD was reduced 25 and 15%, respectively, compared with that of Control. Yield under SDI did not differ significantly from that of the Control and was similar to that of the ED and LD treatments. All the deficit irrigation treatments had some carry-over effects because of a significant decrease in shoot fruitfulness and in bunch mass due to smaller berries. The ED treatment, however, led to a greater reduction in berry growth compared with that of LD. Full irrigation increased pruning mass and leaf area mainly due to larger secondary shoots, and besides delayed grape ripening. Conclusions The SDI treatment resulted in the greatest water use efficiency, ensuring the high yield potential of the cultivar, providing that a threshold value of water stress integral of 35 MPa day during the periods from anthesis to veraison and from veraison to harvest was not surpassed. In addition, it favoured an improved grape composition, particularly in terms of grape sugar accumulation. Significance of the Study Sustained deficit irrigation at 50% of ETc should be applied where water is scarce or expensive, paying attention to possible carry-over effects if water withholding has to be continued for more than three seasons.

Sustained and regulated deficit irrigation of field-grown Merlot grapevines

Background and Aims The aim of this research was to examine the effect of sustained and regulated deficit irrigation regimes on vegetative growth, physiological aspects and yield parameters of field-grown Merlot grapevines. Methods and Results The 4-year trial (2009–2012) in a 13-year-old commercial vineyard of Vitis vinifera cv. Merlot compared the following irrigation treatments: three sustained deficit irrigation treatments and two regulated deficit irrigation treatments. We measured leaf area index and pruning mass to assess vegetative growth, and we recorded stem water potential and gas exchange parameters to examine vine water status. At harvest, we measured yield parameters, crushed berries and analysed must. High water availability during early berry development enhanced vegetative growth and increased berry size and yield. Reducing water supply in order to create a certain level of drought stress during late berry development did not damage yield or berry maturation. Conclusions Regulated deficit irrigation treatment combining higher irrigation from flowering to bunch closure and lower irrigation from bunch closure to harvest has the potential to generate the best balance between vegetative growth, high yield and wine with enhanced colour and aroma compounds. Significance of the Study This study demonstrates the implications of skilled irrigation, in particular the specific effect of irrigation alternation at different phenological stages.

Changes in bioactive compounds and oxidative enzymes of fresh-cut pomegranate arils during storage as affected by deficit irrigation and postharvest vapor heat treatments.

The effect of postharvest vapor heat treatments at 95℃ (4, 7, and 10 s) regarding a conventional sanitizing treatment with 100 mg NaClOl-1 on enzyme activities (phenylalanine ammonia lyase, polyphenol oxidase, and peroxidase), phenolic content, and total antioxidant capacity of fresh-cut pomegranates arils throughout 18 days at 5℃ was studied. Furthermore, the effect of two sustained deficit irrigation (SDI) strategies, compared to a standardly irrigated control (CTRL), was also studied on such quality parameters throughout storage. Arils from CTRL-irrigated fruit registered phenylalanine ammonia lyase, peroxidase, and polyphenol oxidase initial activities of 60.6, 382, and 14.4Ug-1fw, respectively. Arils from sustained deficit irrigation fruit registered 46-58% lower phenylalanine ammonia lyase values while polyphenol oxidase and peroxidase activities did not register great variants (<9%) among both sustained deficit irrigation treatments. Postharvest vapor heat treatments enhanced phenylalanine ammonia lyase activity in those samples from sustained deficit irrigation fruit although no great peroxidase and polyphenol oxidase (<2-5%) increases were observed. Arils from SDI1 fruit registered higher phenolic content than those values reported for CTRL samples. However, phenolic compounds decreased during storage, in a greater extent for sustained deficit irrigation samples, although 7 s arils achieved better phenolic compounds retention in sustained deficit irrigation samples. Vapor heat treatments reduced up to twofold the total antioxidant capacity losses observed in samples sanitized by conventional NaOCl treatment during shelf life. Conclusively, postharvest vapor heat treatment for 7 and 10 s used to extend the shelf life of pomegranate arils up to 18 days at 5℃ reduced the losses of health-promoting compounds during storage compared to conventional NaOCl sanitizing treatment.

Sustained deficit irrigation affects the colour and phytochemical characteristics of pomegranate juice

No information exists on the consequences of water stress on the pomegranate (Punica granatum L.) tree in terms of the quality and health/nutritional properties of its juice. In this study the influence of two different sustained deficit irrigation treatments on the colour, antioxidant activity and total phenolic compound, total anthocyanin, punicalagin and ellagic acid contents of pomegranate juice was assessed. Control plants were irrigated at 75% ETo (crop reference evapotranspiration) in order to ensure non-limiting soil water conditions, while others were subjected to sustained deficit irrigation at 43 and 12% ETo throughout the experimental period. Both moderate (43%) and severe (12%) water stress treatments led to pomegranate juices with a more yellowish colour, lower antioxidant activity and lower total phenolic compound, punicalagin and total anthocyanin contents than those from control plants. Pomegranate juice from trees under sustained deficit irrigation was of lower quality and less healthful than that from trees without water stress. From a nutritional point of view, this means that a reduction in irrigation provides a dramatic decrease in bioactive phenolic compounds, especially anthocyanins and punicalagin, and consequently a lower visual attraction of the juice owing to the weak red colour of the fruit.

Impact of sustained-deficit irrigation on tree growth, mineral nutrition, fruit yield and quality of mango in Spain

Introduction. Mango (Mangifera indica L.) is a crop of major economic impor- tance in the provinces of Malaga and Granada (SE Spain). A field experiment on mango trees was designed to determine the optimum irrigation scheduling over three seasons. The aim was to evaluate the impact of sustained-deficit irrigation (SDI) strategies on fruit yield and quality, tree growth, and mineral status under a Mediterranean subtropical climate. Materials and methods. Three sustained-deficit irrigation treatments were applied to mango trees: SDI-1 (33% ETc), SDI-2 (50% ETc) and SDI-3 (75% ETc). The stress treatments were compared with a control (C-100) irrigated at 100% ET C. The response of fruit yield, number of fruits, fruit size and quality, and macro- and micronutrients in leaves was determined. Results. The SDI-2 treatment proved to be the most appropriate SDI treatment, since it allowed the trees to reach the highest yield (18.4 t·ha -1 ) and the best water-use efficiency (7.14 kg·m -3 ). However, fruit size was higher for trees of the SDI-3 and C-100 treatments, since they reached significantly higher length and width. The total soluble solids were affected by the SDI treatments only for one year, being highest in fruits from trees of the SDI-1 and SDI-2 treatments. Macro- and micronutrients in the leaves were affected by the SDI treatment only for the P, Mg and Mn contents. Conclusion. The SDI treatment providing 50% of ETC is recommended for mango orchards in order to attain the highest yields and the best water-use efficiency under a Mediterranean subtropical climate. Spain / Mangifera indica / irrigation / water use / soil water deficit / irrigation rates / fruits / growth / plant nutrition / yields / quality

PRELIMINARY RESULTS ON THE EFFECTS OF PARTIAL ROOTZONE DRYING, REGULATED DEFICIT IRRIGATION AND SUSTAINED DEFICIT IRRIGATION ON 'VERMENTINO' GRAPEVINE IN SARDINIA (ITALY)

In a two-year trial (2006-2007), Sardinian 'Vermentino' native grapevines were irrigated according to different irrigation strategies: Full Irrigation (FI, control), Partial Root-zone Drying (PRD), Regulated Deficit Irrigation (RDI), Sustained Deficit Irrigation (SDI) and Farmer's aid-irrigation management (FIM). A randomized block design was carried out using irrigation treatments (FI, RDI, SDI, FIM and PRD) as controlled variability factor. Qualitative and quantitative production parameters were determined and plant water stress indicators, i.e. Maximum Daily Shrinkage (MDS) and midday Stem Water Potential (mSWP), were monitored. The main results showed that RDI and SDI water-saving irrigation strategies significantly improved must quality, without the expected sensible reduction of plant productivity, in comparison with FI. The PRD treatment reduced yield in the first year, but increased it in the second year, compared to control (FI). The severe water reduction of the FIM treatment induced a strong yield reduction and must quality worsening, especially in the first year. The MDS was a more powerful plant water stress indicator than the mSWP. The SDI treatment gave the highest water-use efficiency in both years.

Effects of partial rootzone drying on yield, ripening and berry ABA in potted Tempranillo grapevines with split roots

Our objective was to investigate whether grape berry growth and colour development is associated with variation in abscisic acid (ABA) levels during ripening under an irrigation regime of partial rootzone drying (PRD). The study was carried out using container-grown Tempranillo grapevines (established as fruit-bearing cuttings) with a split root system (occupying two contiguous pots) and grown under controlled conditions. Three irrigation treatments were imposed - a control (well watered), and two forms of deficit irrigation, viz. partial rootzone drying (PRD), and sustained deficit irrigation (SDI). Under SDI, a given volume of irrigation water was applied uniformly and simultaneously to both sides of the split roots of each vine. Under the PRD regime, the same total volume of irrigation was applied, but as separate allocations to each side of the split root system in turn, and alternating on a 10-day cycle. Because both deficit treatments received the same total amount of irrigation water (about 50% of the volume applied to controls), we were able to distinguish between the effects of deficit irrigation per se, versus any specific impact PRD might be having on vine performance. Outcomes were as follows. Compared to well-watered control vines, yield per plant, and weight per bunch were both reduced significantly under SDI, but were sustained close to control values under the PRD regime. SDI and PRD thus differed significantly in their respective impacts on vine performance, and comparing just these two forms of deficit irrigation, PRD resulted in greater yield, higher bunch weight, bigger leaf area and increased berry weight compared with the SDI treatment. Moreover, PRD also induced greater accumulation of skin anthocyanins at harvest, compared to SDI. Berry ABA concentration increased continuously throughout veraison, achieving a maximum at the end of this period. The increase of berry ABA concentration was earlier and faster in PRD than in SDI, which exhibited only a slight increase in berry ABA by the end of veraison. These distinctive responses to PRD compared to SDI imply that the alternating wet-dry cycles of PRD, rather than simply a deficit irrigation, as in SDI, had a distinctive effect on growth, ripening and berry composition. Our data imply that these different responses might be related to ABA physiology, and especially to ABA levels in berries during ripening.