Search Results (22)

The coupling of partial root-zone drying (PRD) with nitrogen forms exerts an interactive “water-promoted fertilization” effect, which enhances rice (Oryza sativa L.) growth and development, improves water use efficiency (WUE), mediates the expression of aquaporins (AQPs), and alters root water conductivity. In this study, gene cloning and CRISPR-Cas9 technologies were employed to construct overexpression and knockout vectors of the OsPIP2;1 gene, which were then transformed into rice (cv. Meixiangzhan 2). Three water treatments were set: normal irrigation (CK); partial root-zone drying (PRD); and 10% PEG-simulated water stress (PEG), combined with a nitrogen form ratio of ammonium nitrogen (NH₄⁺) to nitrate nitrogen (NO₃⁻) at 50:50 (A50/N50) for the coupled treatment of rice seedlings. The results showed that under the coupled treatment of PRD and the aforementioned nitrogen form, the expression level of the OsPIP2;1 gene in roots was upregulated by 0.62-fold on the seventh day, while its expression level in leaves was downregulated by 1.84-fold. Overexpression of OsPIP2;1 enabled Meixiangzhan 2 to maintain a higher abscisic acid (ABA) level under different water conditions, which helped rice reduce water potential and enhance water absorption. Compared with the CK treatment, overexpression of OsPIP2;1 increased the superoxide dismutase (SOD) activity of rice under PRD by 26.98%, effectively alleviating tissue damage caused by excessive accumulation of O₂⁻. The physiological and biochemical characteristics of OsPIP2;1-overexpressing rice showed correlations under PRD and A50/N50 nitrogen form conditions, with WUE exhibiting a significant positive correlation with transpiration rate, chlorophyll content, nitrogen content, and Rubisco enzyme activity. Overexpression of OsPIP2;1 could promote root growth and increase the total biomass of rice plants. The application of the OsPIP2;1 gene in rice genetic engineering modification holds great potential for improving important agricultural traits of crops. This study provides new insights into the mechanism by which the AQP family regulates water use in rice and has certain significance for exploring the role of AQP genes in rice growth and development as well as in response to water stress. Full article

The effects of stomatal factors of plant leaves under partial root-zone drying (PRD) have been widely studied. However, the non-stomatal factors and the relationship between photosynthesis with soil moisture have not been explored. In this study, four treatments over-irrigation, full irrigation, moderate water deficit, and severe water deficit were investigated, aiming to evaluate the effects on the diurnal variation of alfalfa leaf photosynthesis under PRD and its relationship with stomatal and non-stomatal limitations, as well as soil moisture. The results showed that any levels of water deficit led to a decrease in the photosynthetic rate (P_n) of alfalfa leaves. Leaves under moderate and severe water deficit displayed a pronounced midday “photosynthetic lunch break,” while those under over- and full irrigation did not display this phenomenon. Before 11:30 a.m., the reduction in P_n was primarily due to stomatal limitations, as evidenced by reduced stomatal conductance (G_s) and decreased intercellular CO₂ concentration (C_i). After 11:30 a.m., non-stomatal limitations became the dominant factor, with both G_s and transpiration rate (T_r) continuing to decrease, while C_i increased, indicating a shift in the limiting factors. Under PRD with moderate water deficit, alfalfa experienced both stomatal and non-stomatal limitations within a single day, leading to a hay yield reduction of 18.6%. Additionally, over-irrigation helped to maintain higher P_n and T_r, increasing alfalfa yield and thus improving water productivity by 33.1%. The correlation coefficients between soil moisture content at 10 cm depths with alfalfa leaf P_n, T_r, and G_s on the photosynthetic measurement day were 0.9864, 0.8571, and 0.8462, respectively. At 20 cm, the correlation coefficients were 0.8820, 0.6943, and 0.6951, respectively. The study concluded that both stomatal and non-stomatal mechanisms contributed to reduced alfalfa P_n in water deficit of PRD. Furthermore, shallow soil moisture also played a crucial role in influencing photosynthetic performance. Full article

Several countries around the world are facing the issue of freshwater availability, where agriculture is highly dependent on irrigation, consuming 70% of this vital resource. Water availability is the most limiting factor for the crop production sector and one of the main regulators of the spatial distribution of plants. It is noted that in recent years, the methods of irrigation water application have been improved. Currently, research is directed towards irrigation strategies that reduce water applications. A partial root drying (PRD) technique involves irrigating one-half of the root zone while leaving the other half in relatively dry soil. This method is used in the production of various crops, such as potatoes and cotton. However, the mechanism of PRD, including the physiological and molecular biological processes involved, is not fully understood. In this study, tomato plants were treated with PRD and nitrogen (N) top-dressing. The results showed that PRD could significantly increase the fruit yield, photosynthetic activities, nitrate reductase activity, and fruit quality in the tomato plants, and PRD could also promote the concentrations of oxygen species (O₂⁻), malondialdehyde (MDA) and proline contents, and activities of antioxidant enzymes. In addition, PRD could enhance stress resistance by increasing disease resistance and NP1 and DRED3 antioxidant enzyme activity. Tomato plants treated with PRD compared to the control showed high photosynthetic activity, high yield, better quality of production, and low leaf blight incidence. Overall, the results indicate that PRD is a feasible approach that could be effectively utilized in tomato fields to improve plant growth and production compared with the control. Full article

Considering the uncertainty of rainfall and prolonged droughts in semiarid regions, optimizing water management through techniques like partial root-zone drying (PRD) is crucial for sustainable banana production. This study aimed to evaluate the ‘Prata-Anã Gorutuba’ banana under irrigation by PRD. The experimental design was randomized blocks with five irrigation strategies (PRD7 50%–50% ETc and 7-day frequency of alternation of the irrigated side—FA, PRD14 50%–50% ETc and 14-day FA, PRD21 50%–50% ETc and 21-day FA, FX 50%–50% ETc and fixed irrigation, and irrigation with 100% ETc on both sides of the plant—FULL) with five replicates. Soil water content, physiological, vegetative, yield characteristics, and water productivity were assessed over two production cycles. PRD on the dry side lowered soil water content below optimal levels for banana cultivation, increased transpiration, and decreased photosynthesis and instantaneous water use efficiency with rising temperatures, while photosynthesis increased with stomatal conductance. PRD reduced plant vigor and delayed flowering in the first cycle. Compared to full and fixed irrigation, PRD conserves water while maintaining crop yields. Water productivity was higher under PRD, with PRD14 (50% ETc and 14-day alternation) offering the best water use efficiency while maintaining yield, making it suitable for ‘Prata-Anã Gorutuba’ banana cultivation. The study recommends PRD for sustainable banana farming in regions with limited water resources, contributing to sustainable agricultural practices and better water management. Full article

Citrus is a subtropical fruit tree with high water requirements. This study aimed to determine the effects of water deficit on an orange orchard subjected to different water-saving strategies. The study was realised in an orange orchard in a semiarid area by adopting four different water management techniques: 100% crop evapotranspiration (control); SSDI—subsurface sustained deficit irrigation; RDI—regulated deficit irrigation; PRD—partial rootzone drying treatment during five growing seasons. The experimental design foresaw a randomised block design with six replicates per treatment (24 index plants). The results of the study showed that the water-saving strategies reduced irrigation water consumption by 25% (SSDI), 33% (RDI), and 49% (PRD) compared to the fully irrigated treatment without yield reduction, thus increasing water use efficiency. Mineral nutrition of the trees was slightly affected by irrigation treatments; element concentration in leaves was generally in the optimal range; only potassium showed values below the recommended leaf concentrations. Regarding fruit quality parameters, the vitamin C concentration in RDI showed significant differences with a value of 62.7 mg 100 mL⁻¹ compared to 58.5 mg 100 mL⁻¹ in the control. Plants subjected to SSDI and PRD strategies showed increased levels of pulp colour index with significant values of 10 and 9.90, respectively, compared to the control (8.44). By implementing targeted water management, citrus growers could save water and increase the ascorbic acid and sugar concentration in the fruits; anthocyanins also increased but not significantly. These findings open new market opportunities for citrus growers in marginal areas, where they cannot rely solely on producing citrus fruits to remain competitive. Full article

Sustainable fruit orchard development in arid areas is severely affected by the scarcity of fresh water. To mitigate the lack of fresh water, the use of low-quality water for irrigation is becoming a common practice in several margin areas. However, salinity is considered one of the most important environmental constraints limiting the successful crop production. Therefore, the effects of deficit irrigation strategies using saline water (3.1 dS m⁻¹) on soil water content, soil salinity, and yield of commercial peach orchard were investigated. Three irrigation treatments were considered: a Control, full irrigated (FI); and partial root-zone drying (PRD₅₀); and deficit irrigation (DI) strategies irrigated at 50% ETc. These levels of water supply allowed for contrasting watering conditions with clear distinction between irrigation treatments. The differential pattern in soil moisture was accompanied by that of soil salinity with an increase in all FI treatments (16–25%). The results indicated that soil salinity increased with increasing water supply and evaporative demand during the growing season from January (3.2 dS m⁻¹) to August (6.6 dS m⁻¹). Deficit irrigation strategies (DI, PRD₅₀) induced more soil salinity along the row emitter compared to the Control due to insufficient leaching fractions. By the end of the growing season, the soil salinity under long-term saline drip irrigation remained stable (5.3–5.7 dS m⁻¹). An efficient leaching action seemed to be guaranteed by rainfall and facilitated by sandy soil texture, as well as the high evaporative demand and the important salt quantity supplied, which maintain the deficit irrigation strategies as valuable tools for water saving and improving water productivity. The significant water saving of 50% of water requirements induced a fruit yield loss of 20%. For this reason, DI and PRD₅₀ could be reasonable irrigation management tools for saving water and controlling soil salinity in arid areas and on deep sandy soil. Full article

The impacts of regulated deficit irrigation (RDI) and partial root zone drying irrigation (PRD) on water productivity (WP), crop water response factor (Ky), and yield of tomato crop (Solanum lycopersicum) were explored in this study using fresh (0.9 dS m⁻¹) and saline (3.6 dS m⁻¹) water under greenhouse conditions. RDI had four ETc (crop evapotranspiration) levels, i.e., 40, 60, 80, and 100%. PRD adopted 100% ETc for all treatments with changes in its application time (first, second, third, and fourth growth stages). Biochar pyrolyzed at 450–500 °C and added at rate of 4%. The results revealed that the Ky ranged between 0.21 and 0.37, indicating that tomato can tolerate a shortage of irrigation water. The highest value of WP (191 kg m⁻³) was found in 40% ETc using fresh water with biochar. The highest yield (20.0 kg m⁻²) was obtained with the application of 100% ETc with fresh water and biochar. Biochar application did not result in favorable yields with saline water due to its high salinity (7.8 dS m⁻¹). The use of PRD in the fourth stage with biochar and fresh water led to the highest yield (20.6 kg m⁻²). Finally, this study recommends the application of biochar only when fresh irrigation water is available in adequate amounts. Full article

Many techniques have been and are being made to find alternatives to water-saving practices. Among them, Partial root drying (PRD), one effective approach, plays a major role in reducing the harmful effects of water deficit stress. Field experiments were carried out on mango trees for a private farm in Egypt over the course of two years, 2020/2021 to 2021/2022, in an area with sandy soil, hot summer conditions, and cold and rainy winter conditions. In the experiment that was carried out, the experimental design included using different irrigation strategies (I1, 100% full irrigation “FI”; I2, 75% FI; I3, 50% FI; and I4 (PRD), 50% FI) in the main plot and different amounts of organic mulch in the soil (L0, no layers of organic soil mulch, used as a control; L1, a single layer of organic soil mulch; L2, two layers of organic soil mulch; and L3, three layers of organic soil mulch) in subplots of the main plot in order to inspect the impact of the treatments on yield, water productivity, and energy usage under arid conditions. To meet the study’s objective, two field experiments were carried out at a private farm. Our results demonstrate a general decrease in water stress and salt accumulation inside the root-zone area with PRD and L3. During the 2020/2021 and 2021/2022 seasons the PRD strategy increased fruit yields by 3.7 and 7.3% and water productivity by 51.9 and 53.1%, respectively, compared with the control treatment (I1) while reducing the amount of applied irrigation water by 50%. The PRD strategy along with organic mulching showed superior results with respect to increasing mango yields and water productivity. In general, PRD can be used as a good technique to save water and energy by up to 50% while enhancing productivity, ultimately improving mango yields under arid climatic conditions. Thus, it may prove a good adaptation strategy for current and future water shortage scenarios involving climate change. Full article

The production of olive oil in Portugal and other countries of the Mediterranean region has greatly increased in recent years. Intensification efforts have focused on the growth of the planted area, but also on the increase of the orchards density and the implementation of irrigation systems. Concerns about possible negative impacts of modern olive orchard production have arisen in the last years, questioning the trade-offs between the production benefits and the environmental costs. Therefore, it is of great importance to review the research progress made regarding agronomic options that preserve ecosystem services in high-density irrigated olive orchards. In this literature review, a keywords-based search of academic databases was performed using, as primary keywords, irrigated olive orchards, high density/intensive/hedgerow olive orchards/groves, irrigation strategies, and soil management. Aside from 42 general databases, disseminated research, and concept-framing publications, 112 specific studies were retrieved. The olive orchards were classified as either traditional (TD) (50–200 trees ha⁻¹), medium-density (MD) (201–400 trees ha⁻¹), high-density (HD) (401–1500 trees ha⁻¹), or super-high-density (SHD) orchards (1501–2500 trees ha⁻¹). For olive crops, the ETc ranged from 0.65 to 0.70, and could fall as low as 0.45 in the summer without a significant decrease in oil productivity. Several studies have reported that intermediate irrigation levels linked with the adoption of deficit irrigation strategies, like regulated deficit irrigation (RDI) or partial rootzone drying (PRD), can be effective options. With irrigation, it is possible to implement agroecosystems with cover crops, non-tillage, and recycling of pruning residues. These practices reduce the soil erosion and nutrient leaching and improve the soil organic carbon by 2 to 3 t C ha⁻¹ year⁻¹. In this situation, in general, the biodiversity of plants and animals also increases. We expect that this work will provide a reference for research works and resource planning focused on the improvement of the productive and environmental performance of dense irrigated olive orchards, thereby contributing to the overall enhancement of the sustainability of these expanding agroecosystems. Full article

The peach (Prunus persica L.) is one of Tunisia’s major commercial fruit crops and is considered one of the biggest water consumers of all crops. In warm and arid areas of southern Tunisia, irrigation is necessary to ensure orchard longevity and high yield and fruit quality. Nevertheless, under water-scarcity conditions and low water quality, water management should rely on efficient deficit irrigation strategies. In this study, sustained deficit irrigation (DI) and partial root-zone drying (PRD₅₀) at 50% of crop evapotranspiration (ETc) were evaluated for their impact on the primary and secondary metabolites of the peach fruit of early cultivar Flordastar grown in the Tataouine region. A full irrigation (FI) treatment at 100%, etc., was used as a control treatment. Color, dry-matter content, firmness, organic acids, sugars, phenolic compounds, vitamin C, β-carotene and minerals were assessed on harvested mature fruits. Dry-matter content and firmness increased significantly under DI and PRD₅₀ (13% and 15.5%). DI fruit had the highest soluble-solid content (SSC), reaching Brix values of 14.3°. Fruit sorbitol and sucrose contents were not affected by Di and PRD₅₀. Higher glucose in fruit juice was observed in PRD₅₀ (23%) and DI (21.5%) compared to FI, which had the highest malic acid content (33.5–37%). Quinic and citric acids decreased with DI and PRD₅₀, while almost all individual phenolic compounds increased with deficit irrigation. Hydroxycinnamates and anthocyanins were significantly higher in fruits harvested from DI and PRD₅₀ treatments. Proanthocyanidins (catechin and epicatechin) were only improved by DI, while flavone compounds and vitamin C were not affected by irrigation restrictions. β-carotene was higher in fruits yielded under FI (0.71 mg/100 g DM) than DI and PRD₅₀ (0.21–0.43 mg/100 g DM). Macro- and micronutrients significantly increased in DI and PRD₅₀ fruit. A significant difference between DI and PRD₅₀ fruits was observed for Zn and Fe concentrations. This research highlights the positive impact of reduced irrigation on bioactive-fruit quality attributes and the suitability of PRD₅₀ and DI as tools for irrigation management in arid areas of southern Tunisia, contributing to water-saving in orchards and the improvement of fruit commercial value. Full article

This work assessed the effects of the sustained (during the whole berry growth) and regulated (at post-veraison) practices of deficit irrigation on water relations, yield components and berry quality in a commercial vineyard of ‘Crimson Seedless’ table grapes. For this, five irrigation treatments were established during a complete irrigation season (from April to October): (i) Control (CTL) irrigated to 110% crop evapotranspiration (ET_c); (ii) Regulated Deficit Irrigation (RDI) irrigated at 50% of CTL during the non-critical period of post-veraison; (iii) Sustained Deficit Irrigation (SDI), irrigated at 50% of CTL throughout the entire berry growing season; (iv) Partial Root-Zone Drying (PRD), irrigated similar to RDI but alternating the irrigation applied on the dry side every 10–14 days; (v) Sustained Partial Root-Zone Drying (SPRD), irrigated as SDI but alternating the irrigation on the dry side every 10–14 days. RDI and PRD received 24% and 28% less water than CTL, respectively. These reductions were higher in SDI and SPRD (65% and 53%, respectively). Total yield was not affected by any DI strategy. Only significantly lower productive values were observed in the weight and height of the berries as compared to CTL. However, the color parameters evaluated increased in all the DI treatments, being slightly higher in SDI and SPRD as compared with RDI and PRD. In addition, total soluble solids (TSS) were significantly higher in SDI, compared to other irrigated counterparts. Our findings showed that the application of water deficit during the entire period of berry growth using SDI and SPRD can be considered for irrigation scheduling in ‘Crimson Seedless’ table grapes when the aim is to solve the trouble of insufficient reddish color of the berries. Full article

For three consecutive years (2015–2017), two deficit irrigation (DI) strategies were used in a 12-year old vineyard (cv. ‘Crimson Seedless’) to implement a sustainable irrigation protocol according to the available water for the farmer. Four different irrigation treatments were assessed: (i) Control (CTL), irrigated to satisfy the maximum crop water requirements throughout the entire growing season; two DI treatments irrigated as CTL except during post-veraison, when the vines were irrigated at 50% CTL: (ii) Regulated Deficit Irrigation (RDI); and (iii) Partial Root Drying (PRD), alternating the wet and dry sides of the root zone, and (iv) irrigated according to the criteria followed by the farmer (FARM), and conditioned by the availability of water each season. The DI strategies resulted in a 50% increase in water use efficiency in the first two years and 81% during the third year. Weekly deficit irrigation protocols are proposed, which specify a maximum difference of 0.22 MPa of midday stem water potential with respect to well-watered vines for a range of irrigation water availabilities between 4000 and 7000 m³ ha⁻¹. An applied water prediction model based on the Gaussian regression using day of the year and maximum temperature of the day is also proposed. Full article

This study aims to evaluate the Partial Root Zone Drying Irrigation System (PRD) as one of the modern technologies that provide irrigation water and increase the efficiency of its use on potato crop. The effect of applying the PRD conventional deficit irrigation (CDI) on the efficiency and water saving in potato crops using the drip surface (S) and subsurface (SS) irrigation methods were investigated. SALTMED model used to predict soil moisture and salinity distribution, soil nitrogen dynamics, and yield of potato crop using the different irrigation levels (150%, 100%, and 50% of Crop evapotranspiration (ETc)). The study showed that the water use efficiency (WUE) decreases with increasing levels of irrigation water, as it ranged between 2.96 and 8.38 kgm⁻³, 2.77 and 7.01 kgm⁻³ for surface irrigation PRD and CDI, respectively, when the amounts of irrigation water varied from 308 mm to 1174 mm, respectively. The study showed that the irrigation efficiencies were the highest when using PRD system in all treatments when irrigating the potato crop during the spring season, and it was more efficient in the case of using subsurface irrigation method. The results show that the soil moisture (SM) was high in 25–45 cm at 150% of ETc was 0.166 and 0.263 m³m⁻³ for the first and last stages of growth, respectively. 100% of ETc, (SM) was 0.296 m³m⁻³ at 0–25 cm, 0.195 m³m⁻³ at 25–45 cm, 0.179 m³m⁻³ at 45–62 cm, depths, respectively. whereas 50% of ETc, (SM) was 0.162 m³m⁻³ at 0–25 cm, 0.195 m³m⁻³ at 25–85 cm, depths. At 100% of ETc, soil salinity was 5.15, 4.37, 3.3, and 4.5 dSm⁻¹, whereas at 50%, ETc, these values were 5.64, 9.6, 3.3, and 4.2 dSm⁻¹. Statistical indicators showed that the model underestimated yield, for 150%, 100%, and 50% of ETc. Therefore, it can be concluded that yield and WUE using PRD systems were the highest in the potato crop compare to CDI surface and sub-surface, and SALTMED model can predict the moisture distribution, salinity, and yield of potatoes after accurate adjustment. Full article

Water scarcity and the increasing demand for irrigation in olive orchards lead to the adoption of deficit irrigation approaches to save water. A partial rootzone drying (PRD) irrigation technique has been proposed for woody crops as an agronomic practice to improve water productivity. This study was conducted to evaluate the effects of this irrigation strategy on water relations and transpiration of olive trees (cv. Cobrançosa) under climate conditions in the northeast of Portugal during the summer season of 2014. Two irrigation treatments were used: control (FI), irrigated with 100% of the estimated crop evapotranspiration (ET) and PRD₅₀, irrigated with 50% of the control (FI) on one side and switching every two weeks. Whole tree transpiration (T) was quantified by sap flow, which was monitored within the trunks of both the control (FI) and deficit irrigated (PRD₅₀) trees using the compensation heath-pulse technique. Foliage gas exchange and water potentials were determined throughout the experimental period. During the summer, daily transpiration reached roughly 27 and 43 L d⁻¹ for PRD₅₀ and FI olive trees, respectively, with a clear reduction of 37% in PRD₅₀ olive trees. PRD₅₀ showed statistically comparable values of water potentials to the control, which appeared to prevent an excessive drop in tree water status by modulating stomatal closure. Full article

The tomato is an important horticultural crop, the cultivation of which is often under influence of abiotic and biotic stressors. Grafting is a technique used to alleviate these problems. Shortage of water has stimulated the introduction of new irrigation methods: deficit irrigation (DI) and partial root-zone drying (PRD). This study was conducted in two spring–summer season experiments to evaluate the effects of three irrigation regimes: full irrigation (FI), PRD and DI on vegetative growth, leaf gas-exchange parameters, yield, water-use efficiency (WUE), nutrients profile and fruit quality of grafted tomatoes. In both years, the commercial rootstocks Emperador and Maxifort were used. In the first year, the scion cultivar Clarabella was grown on one stem and in the second year the cultivar Attiya was grown on two stems. Self-grafted cultivars were grown as a control. In both experiments, higher vegetative traits (leaf area and number, height, shoot biomass) were recorded in tthe plants grafted on commercial rootstocks. The stomatal conductance and transpiration rate were higher under FI. Under DI, transpiration was lowest and photosynthetic WUE was highest. Photosynthetic rate changed between irrigation treatments depending on plant type. In both years, the total yield was highest in grafted plants as result of more and bigger fruits per plant. In the 2nd year, grafted plants under FI had higher yield compared to PRD, but not to DI, while self-grafted plants did not differ between irrigation treatments. WUE was highest in DI and PRD treatments and in grafted plants. Leaf N, P, K and Ca was highest in tthe plants grafted on Emperador and Maxifort, while more Mg was measured in self-grafted plants. More Ca and Mg were recorded in tthe plants under DI and PRD. Fruit mineral concentrations were higher in tthe plants grafted on commercial rootstocks. Total soluble solids differed between irrigation regarding plant types, while fruit total acidity was higher in Emperador and Maxifort. In conclusion, our study showed that grafted plants could be grown under DI with minor yield reduction with 30–40% less water used for irrigation. Moderate DI could be used before PRD for cultivation of grafted tomato and double stemmed plants did not show negative effect on tomato yield so it can be used as standard under reduced irrigation. Full article