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1.
This study assesses the long-term suitability of regulated (RDI) and sustained deficit irrigation (SDI) implemented over the first six growing seasons of an almond [Prunus dulcis (Mill.) D.A. Webb] orchard grown in a semiarid area in SE Spain. Four irrigation treatments were assessed: (i) full irrigation (FI), irrigated to satisfy maximum crop evapotranspiration (100% ETc); (ii) RDI, as FI but receiving 40% ETc during kernel-filling; (iii) mild-to-moderate SDI (SDImm), irrigated at 75–60% ETc over the entire growing season; and (iv) moderate-to-severe SDI (SDIms), irrigated at 60–30% ETc over the whole season. Application of water stress from orchard establishment did not amplify the negative effects of deficit irrigation on almond yield. Irrigation water productivity (IWP) increased proportionally to the mean relative water shortage. SDIms increased IWP by 92.5%, reduced yield by 29% and applied 63% less irrigation water. RDI and SDImm showed similar productive performances, but RDI was more efficient than SDImm to increase fruiting density and production efficiency (PE). We conclude that SDIms appears to be a promising DI option for arid regions with severe water scarcity, whereas for less water-scarce areas RDI and SDImm behaved similarly, except for the ability of RDI to more severely restrict vegetative development while increasing PE.  相似文献   

2.
The aim of this study was to quantify and compare the effects of two different deficit irrigation (DI) strategies (regulated deficit irrigation, or RDI, and partial rootzone drying, PRD) on almond (Prunus dulcis (Mill.) D.A. Webb) fruit growth and quality. Five irrigation treatments, ranging from moderate to severe water restriction, were applied: (i) full irrigation (FI), irrigated to satisfy the maximum crop water requirements (ETc); (ii) regulated deficit irrigation (RDI), receiving 50% of ETc during the kernel-filling stage and at 100% ETc throughout the remaining periods; and three PRD treatments – PRD70, PRD50 and PRD30 – irrigated at 70%, 50% and 30% ETc, respectively, during the whole growth season. The DI treatments did not affect the overall fruit growth pattern compared to the FI treatment, but they had a negative impact on the final kernel dry weight for the most stressed treatments. The allocation of water to the different components of the fruit, characterized by the fresh weight ratio of kernel to fruit, appeared to be the process most clearly affected by DI. Attributes of the kernel chemical composition (lipid, protein, sugar and organic acid contents) were not negatively affected by the intensity of water deprivation. Overall, our results indicated that PRD did not present a clear advantage (or disadvantage) over RDI with regard to almond fruit growth and quality.  相似文献   

3.
During four growing seasons, 10-year-old apricot trees (Prunus armeniaca L., cv. ‘Búlida’) were submitted to three different drip irrigation regimes: (1) a control treatment, irrigated at 100% of seasonal crop evapotranspiration (ETc), (2) a continuous deficit irrigation (DI) treatment, irrigated at 50% of the control treatment, and (3) a regulated deficit irrigation (RDI) treatment, irrigated at 100% of ETc during the critical periods, which correspond to stage III of fruit growth and 2 months after harvest (early postharvest), and at 25% of ETc during the rest of the non-critical periods in the first two growing seasons and at 40% of ETc in the third and fourth. Soil–plant–water relation parameters were sensitive to the water deficits applied, which caused reductions in leaf and soil water potentials. The longer and severer deficits of the RDI treatment decreased fruit yield in the first two seasons. The RDI treatment pointed to two threshold values that defined the level at which both plant growth and yield were negatively affected with respect to the control treatment: (1) a predawn leaf water potential of around −0.5 MPa during the critical periods, and (2) a 22% drop in irrigation water. The total yield obtained in the DI treatment was significantly reduced in all the years studied due to the lower number of fruits per tree. No changes in the physical characteristics of fruits were observed at harvest. RDI can be considered a useful strategy in semiarid areas with limited water resources.  相似文献   

4.
We investigated the long-term effects of different deficit irrigation (DI) options on tree growth, shoot and leaf attributes, yield determinants and water productivity of almond trees (Prunus dulcis, cv. Marta) grown in a semiarid climate in SE Spain. Three partial root-zone drying (PRD) irrigation treatments encompassing a wide range of water restriction (30%, 50% and 70% of full crop requirements, ETc) and a regulated deficit irrigation treatment (RDI, at 50% ETc during kernel-filling) were compared over three consecutive growth seasons (2004–2006) to full irrigation (FI). The results showed that all deficit irrigation treatments have a negative impact on trunk growth parameters. The magnitude of the reduction in trunk growth rate was strongly correlated through a linear relationship with the annual volume of water applied (WA) per tree. Similarly, a significant relationship was found between WA and the increase in crown volume. In contrast, leaf-related attributes and some yield-related parameters (e.g., kernel fraction) were not significantly affected by the irrigation treatments. Except in PRD70, individual kernel weight was significantly reduced in the deficit irrigated treatments. Kernel yield, expressed in percent of the maximum yield observed in the FI treatment, showed a linear decrease with decreasing WA and a slope of 0.43, which implies that a 1% decrease in water application would lead to a reduction of 0.43% in yield. Water productivity increased drastically with the reduction of water application, reaching 123% in the case of PRD30. Overall, our results demonstrate the prevalence of direct and strong links between the intensity of the water restriction under PRD – i.e., the total water supply during the growing season – and the main parameters related to tree growth, yield and water productivity. Noteworthy, the treatments that received similar annual water volumes under contrasted deficit irrigation strategies (i.e., PRD70 and RDI) presented a similar tree performance.  相似文献   

5.
The reduction in agricultural water use in areas of scarce supplies can release significant amounts of water for other uses. As improvements in irrigation systems and management have been widely adopted by fruit tree growers already, there is a need to explore the potential for reducing irrigation requirements via deficit irrigation (DI). It is also important to quantify to what extent the reduction in applied water through DI is translated into net water savings via tree evapotranspiration (ET) reduction. An experiment was conducted in a commercial pistachio orchard in Madera, CA, where a regulated deficit irrigation (RDI) program was applied to a 32.3-ha block, while another block of the same size was fully irrigated (FI). Four trees were instrumented with six neutron probe access tubes each, in the two treatments and the soil water balance method was used to determine tree ET. Seasonal irrigation water in FI, applied through a full-coverage microsprinkler system, amounted to 842 mm, while only 669 mm were applied in RDI. Seasonal ET in FI was 1024 mm, of which 308 mm were computed as evaporation from soil (Es). In RDI, seasonal ET was reduced to 784 mm with 288 mm as Es. The reduction in applied water during the deficit period amounted to 147 mm. The ET of RDI during the deficit period was also reduced relative to that of FI by 133 mm, which represented 33% of the ET of FI during the deficit irrigation period. There was an additional ET reduction in RDI of about 100 mm that occurred in the post-deficit period.  相似文献   

6.
The effects of mid-summer regulated deficit irrigation (RDI) treatments were investigated on Navel Lane Late citrus trees over four seasons. Water restrictions applied from July until mid-September were compared with irrigation at full crop evapotranspiration (ETc). Two degrees of water restrictions were imposed: (1) RDI-1, irrigated at around 50% ETc and, (2) RDI-2, irrigated at 30–40% ETc. In addition, threshold values of midday stem water potential (Ψs) of ?1.3 to ?1.5 MPa for RDI-1 and of ?1.5 to ?1.7 MPa for RDI-2 were also taken into account. Results showed that Navel Lane Late is a citrus cultivar sensitive to water deficit since both RDI strategies reduced fruit size every year and water use efficiency in RDI trees was similar to control trees. However, the RDI-1 strategy allowed water savings up to 19% without reduction in yield when the water stress integral did not surpass 70 MPa day. RDI improved fruit quality, increasing total soluble solids and titratable acidity, while the fruit maturity was delayed. In conclusion, we suggest that RDI-1 strategy since it did not significantly impair the economic return can be applied in commercial orchards in case of water scarcity. Nevertheless, Navel Lane Late fruit is sensitive to water deficit and the fruit weight can be detrimentally affected.  相似文献   

7.
The effects of different deficit-irrigation strategies on plant-water status and yield were studied for 5 years in early-maturing peach trees (cv. Flordastar) growing under Mediterranean climatic conditions. The deficit-irrigation (DI) treatments were continuous, regulated (RDI), partial root-zone drying and a soil water content-based treatment. Peach fruit yield was more affected by post-harvest irrigation than by pre-harvest irrigation. Deficit irrigation for this cultivar produced significant water savings but caused a yield penalty, with the RDI treatment showing the clearest manifestation of this. Deficit irrigation in general affected the number of fruits per tree more than fruit size. Average stem water potential threshold values for summer (July–August–September) should be maintained above ?0.9 MPa if yields are not to decrease by more than 10 %. The marginal water use efficiency value of 0.07 for the irrigation range studied indicates that the maximum benefit, derived from a linear production function, will always occur at the limit of the water constraint prior to maximum yield values. Decision-makers should apply the minimal amount of irrigation water that allows maximum yields. Since DI treatments decrease yield due to smaller tree sizes, it is advisable that thinning practices be adapted when deficit irrigation is imposed.  相似文献   

8.
A cost–benefit analysis was performed for a mature, commercial almond plantation [Prunus dulcis (Mill.) D.A. Webb] cv. Cartagenera in Southeastern Spain to determine the profitability of several regulated-deficit irrigation (RDI) strategies under subsurface drip irrigation conditions (SDI), compared to an irrigation regime covering 100% crop evapotranspiration (ETc). The plantation was subjected to three drip irrigation treatments for 4 years: T1 (control, surface drip irrigation)—irrigated at 100% ETc throughout the growth cycle, T2 (RDI treatment under SDI)—an irrigation strategy that provided 100% ETc except during the kernel-filling period, when only 20% ETc was provided and T3 (RDI treatment under SDI)—an irrigation strategy that provided 100% ETc except during the kernel-filling period (20% ETc) and post-harvest (50% ETc). A 45% water saving was achieved with strategy SDI T3, while almond production was reduced by only 17%, increasing water use efficiency compared to the control irrigation regime. SDI T3 had fixed overhead costs 9% higher than T1, however, the operating costs were 21% lower for SDI T3 compared to T1. This reduction in costs was basically due to the 45% saving in the cost of water and the corresponding saving in electricity. The break-even point was lower in SDI T3; each kilogram of almonds cost 0.03€ less to produce than in the control conditions. Related to this, the maximum price of water for obtaining profit 0 was 0.21€ m−3 for SDI T3 compared to 0.18€ m−3 for T1, indicating that higher water costs can be borne in SDI T3 (up to 0.03€ m−3 more expensive). Finally the profit/total costs ratio (used as an expression of the overall profitability of the orchard) indicated a greater profitability for the treatment SDI T3 compared to T1 (10.46 and 9.27%, respectively). The RDI strategy SDI T2 did not show economic indices or water use efficiency as much as those of SDI T3. From these results we conclude that RDI applied during kernel-filling and post-harvest under SDI conditions, and specifically the irrigation strategy SDI T3, may be considered economically appropriate in semiarid conditions in order to save water and improve water use efficiency.  相似文献   

9.
Yield and water productivity of potatoes grown in 4.32 m2 lysimeters were measured in coarse sand, loamy sand, and sandy loam and imposed to full (FI), deficit (DI), and partial root-zone drying (PRD) irrigation strategies. PRD and DI as water-saving irrigation treatments received 65% of FI after tuber bulking and lasted for 6 weeks until final harvest. Analysis across the soil textures showed that fresh yields were not significant between the irrigation treatments. However, the same analysis across the irrigation treatments revealed that the effect of soil texture was significant on the fresh yield and loamy sand produced significantly higher fresh yield than the other two soils, probably because of higher leaf area index, higher photosynthesis rates, and “stay-green” effect late in the growing season. More analysis showed that there was a significant interaction between the irrigation treatments and soil textures that the highest fresh yield was obtained under FI in loamy sand. Furthermore, analysis across the soil textures showed that water productivities, WP (kg ha−1 fresh tuber yield mm−1 ET) were not significantly different between the irrigation treatments. However, across the irrigation treatments, the soil textures were significantly different. This showed that the interaction between irrigation treatments and soil textures was significant that the highest significant WP was obtained under DI in sandy loam. While PRD and DI treatments increased WP by, respectively, 11 and 5% in coarse sand and 28 and 36% in sandy loam relative to FI, they decreased WP in loamy sand by 15 and 13%. The reduced WP in loamy sand was due to nearly 28% fresh tuber yield loss in PRD and DI relative to FI even though ET was reduced by 9 and 11% in these irrigation treatments. This study showed that different soils will affect water-saving irrigation strategies that are worth knowing for suitable agricultural water management. So, under non-limited water resources conditions, loamy sand produces the highest yield under full irrigation but water-saving irrigations (PRD and DI) are not recommended due to considerable loss (28%) in yield. However, under restricted water resources, it is recommended to apply water-saving irrigations in sandy loam and coarse sand to achieve the highest water productivity.  相似文献   

10.
The use of Regulated deficit irrigation (RDI) in almond, applied during the kernel-filling phase, was evaluated over four consecutive years. To determine the reference optimal irrigation rate, three treatments were applied: T-100, which was irrigated by replacing crop evapotranspiration; T-130, which was irrigated by applying 30% more water than in T-100 and T-70, which received 30% less water than T-100. The RDI treatment received the same irrigation rate as T-100, but during the kernel-filling period irrigation was reduced to 20% of T-100. The optimum yield response was observed in treatment T-100, while T-130 trees never improved on T-100 kernel production over the 4 years of the study. During the first two experimental years, kernel dry matter accumulation did not decrease with drought in the RDI treatment. However, both cropping and kernel growth were reduced during the third and fourth years of the experiment. A possible explanation for this decrease could be found in a hypothetical depletion of the carbohydrate reservoir in RDI trees and also to the negative soil water balance that was evident in the T-70 and RDI treatments during winter and spring of the last 2 years. Although yield reductions for RDI trees were significant (20% with respect to T-100), the water savings obtained (about 60% of that applied with respect to T-100), may help to promote the adoption of RDI in areas, where water availability has been reduced. Bearing in mind the water conservation aspect in almond, RDI, as applied in this case, seemed more interesting than a seasonal sustained deficit irrigation strategy like T-70.  相似文献   

11.
Precision irrigation management and scheduling, as well as developing site- and cultivar-specific crop coefficient (Kc), and yield response factor to water deficit (ky) are very important parameters for efficient use of limited water resources. This study investigated the effect of deficit irrigation, applied at different growth stages of peanut with sprinkler irrigation in sandy soil, on field peanut evapotranspiration (ETc), yield and yield components, and water use efficiencies (IWUE and WUE). Also, yield response factor to water deficit (ky), and site- and cultivar-specific Kc were developed. Four treatments were imposed to deficit irrigation during late vegetative and early flowering, late flowering and early pegging, pegging, and pod formation growth stages of peanut, and compared with full irrigation in the course of the season (control). A soil water balance equation was used to estimate crop evapotranspiration (ETc). The results revealed that maximum seasonal ETc was 488 mm recorded with full irrigation treatment. The maximum value of Kc (0.96) occurred at the fifth week after sowing, this value was less than the generic values listed in FAO-33 and -56 (1.03 and 1.15), respectively. Dry kernels yield among treatments differed by 41.4%. Deficit irrigation significantly affected yields, where kernels yield decreased by 28, 39, 36, and 41% in deficit-irrigated late vegetative and early flowering, late flowering and early pegging, pegging, and pod formation growth stages, respectively, compared with full irrigation treatment. Peanut yields increased linearly with seasonal ETc (R2 = 0.94) and ETc/ETp (R2 = 0.92) (ETp = ETc with no water stress). The yield response factor (ky), which indicates the relative reduction in yield to relative reduction in ETc, averaged 2.9, was higher than the 0.7 value reported by Doorenbos and Kassam [Doorenbos, J., Kassam, A.H., 1979. Yield response to water. FAO Irrigation and Drainage Paper 33, Rome, Italy, 193 pp.], the high ky value reflects the great sensitivity of peanut (cv. Giza 5) to water deficit. WUE values varied considerably with deficit irrigation treatments, averaging 6.1 and 4.5 kg ha−1 mm−1 (dry-mass basis) for pods and kernels, respectively. Differences in WUE between the driest and wettest treatment were 31.3 and 31.3% for pods and kernels, respectively. Deficit irrigation treatments, however, impacted IWUE much more than WUE. Differences in IWUE between the driest and wettest treatment were 33.9 and 33.9% for pods and kernels, respectively. The results revealed that better management of available soil water in the root zone in the course of the season, as well as daily and seasonal accurate estimation of ETc can be an effective way for best irrigation scheduling and water allocation, maximizing yield, and optimizing economic return.  相似文献   

12.
Cost-benefit analysis was performed to determine the profitability of producing wine grapes under different irrigation regimes. Vines irrigated by regulated deficit irrigation (RDI) and partial root-zone drying (PRD) were compared with vines grown under full irrigation in a typical vineyard in a semiarid environment with scarce water resources (south-eastern Spain) during three consecutive years. Five irrigation treatments were applied. The Control treatment irrigated at 60% of the ETc (Crop evapotranspiration) throughout the orchard cycle. PRD-1 and RDI-1 provided deficit irrigation from fruit set to harvest (irrigated 30% ETc) and post-harvest (45% ETc). PRD-2 and RDI-2 provided deficit irrigation from fruit set to harvest (irrigated 15% ETc) and post-harvest (45% ETc). From an economic point of view, only the Control, PRD-1 and RDI-1 treatments were economically viable since their profitability indicators were positive, although low, especially PRD-1. The more severe deficit irrigated treatments (PRD-2 and RDI-2) were unviable. The most profitable treatment was the Control which had a Net Margin/total cost ratio (NM/C) (representing the overall profitability of the vineyard) of 25.37% compared with the 1.90% of RDI-1 and 0.57% of PRD-1. The threshold price of water indicates that only the Control remains profitable with higher water prices of up to 0.46 € m−3. When the cost-benefit analysis took into account the extra quality achieved in PRD-2 and RDI-2, it indicated that these treatments, which were otherwise economically unviable, achieved high returns (17 and 16%, respectively) and were close to the Control treatment. Thus, a low or moderate bonus that encourages extra berry quality for premium wine production would make deficit irrigation practices profitable. Moreover, the financial indices estimated suggest that in the present situation, and with our soil and climatic conditions, PRD is less economically profitable (higher installation cost, lower NM/C, and threshold price of water) than RDI under the same conditions.  相似文献   

13.
The level of irrigation restriction to apply in a deficit irrigation (DI) programme for sustainable peach (‘Baby gold 6’) production was investigated. The experiment involved four irrigation treatments over five consecutive seasons (2007–2011). They were full irrigation (control), reducing irrigation by 20 % during the first half of stage III (DI-80 %), withholding irrigation until reaching a light stress level (DI-L) and withholding irrigation until reaching a moderate stress level (DI-M). The withholding of irrigation in both DI-L and DI-M was applied only during stage II and postharvest periods and was based on midday stem water potential thresholds (Ψ stem). For the DI-L treatment ?1.5 MPa was used in both periods, and for DI-M ?1.8 and ?2.0 MPa were used during stage II and postharvest, respectively. Average Ψ stem values during DI periods were approximately ?1.4 and ?1.2 MPa for DI-M and DI-L, respectively. The pre-defined thresholds required to trigger irrigation were rarely reached. No significant differences between treatments were found in terms of yield in any experimental year. However, DI-M and to a lesser extent DI-L had lower final fruit fresh mass at harvest related to lower Ψ stem after three consecutive years of the experiment (during 2010 and 2011). Therefore, in terms of fruit size, DI was not sustainable. Rather than lowering Ψ stem thresholds, we recommend discontinuing DI after 3-year application.  相似文献   

14.
Deficit irrigation after harvest has been proven to be a more profitable strategy for producing loquats due to its effects on promoting earlier flowering and harvest date next season. To determine water savings which most advance flowering and harvest dates, an experiment was established to compare phenology, fruit quality and yield in ‘Algerie’ loquats over two consecutive seasons. In this experiment some trees were programmed to receive 50%, 25% or 0% of the water applied to controls (RDI50%, RDI25%, and RDI0%, respectively) from mid-June to the end of July (6 weeks). Fully irrigated trees acted as first controls while trees undergoing previously tested postharvest deficit irrigation (25% of water applied to controls; RDILong) from early June up to the end of August (13 weeks of RDI total) acted as second controls. All deficit irrigation treatments promoted earlier flowering when compared to fully irrigated trees; the greatest advancement in full bloom date (27 days) was achieved with severe short term RDI (RDI0% and RDI25%). The trees suffering an extended period of water stress advanced full bloom date but to a lesser extent (13 and 18 days; 2004/2005 and 2005/2006, respectively). Earlier bloom derived in an earlier harvest date without detrimental effects on fruit quality and productivity. In this regard, the most severe RDI (RDI0%) advanced mean harvest date the most (7 and 9 days, depending on the season), and increased the percentage of precocious yield to the highest extent. Productivity was not diminished by reduced irrigation in either season. Fruit size and grading was enhanced thanks to RDI in both seasons. Earliness and better fruit class distribution under RDI also improved fruit value and gross revenue enabling farmers both to increase earning and economize on water.  相似文献   

15.
Irrigation techniques that reduce water applications are increasingly applied in areas with scarce water resources. In this study, the effect of two regulated deficit irrigation (RDI) strategies on peach [Prunus persica (L.) Batsch cv. “Catherine”] performance was studied over three growing seasons. The experimental site was located in Murcia (SE Spain), a Mediterranean region. Two RDI strategies (restricting water applications at stage II of fruit development and postharvest) based on stem water potential (Ψs) thresholds (?1.5 and ?1.8 MPa during fruit growth and ?1.5 and ?2.0 MPa during postharvest) were compared to a fully irrigated control. Soil water content (θv), Ψs, gas exchange parameters, vegetative growth, crop load, yield and fruit quality were determined. RDI treatments showed significantly lower values of θv and Ψs than control trees when irrigation water was restricted, causing reductions in stomatal conductance and photosynthesis rates. Vegetative growth was reduced by RDI, as lower shoot lengths and pruning weights were observed under those treatments when compared to control. However, fruit size and yield were unaffected, and fruit quality was slightly improved by RDI. Water savings from 43 to 65 % were achieved depending on the year and the RDI strategy, and no negative carryover effect was detected during the study period. In conclusion, RDI strategies using Ψs thresholds for scheduling irrigation in mid–late maturing peach trees under Mediterranean conditions are viable options to save water without compromising yield and even improving fruit quality.  相似文献   

16.
The effects of sustained and regulated deficit irrigation (SDI and RDI) on “Mollar de Elche” pomegranate tree performance were investigated in a field trial conducted over three consecutive seasons. In the RDI regimes, severe water restrictions were applied during one of three phases: flowering and fruit set, fruit growth, or the final phase of fruit growth and ripening. In another approach, SDI was applied by watering trees at 50 % of the estimated crop water needs (ETc) during the entire season. Results showed that even after three consecutive seasons of water restrictions, similar yield levels were obtained in SDI and Control trees watered at 100 % ETc. This was because a 22 % reduction in average fresh fruit weight recorded in the SDI treatment was compensated by an increase in 28 % in the quantity of fruit collected per tree. This was most likely due to a reduction in the fall of the reproductive organs. However, the SDI strategy led to a reduction in 28 % in the yield value when fruits are sold for fresh fruit markets. Water restrictions applied only during flowering and fruit set also resulted in an increase in the quantity of fruit collected per tree, with only a slight reduction in fruit weight and without affecting the yield value. On the other hand, severe water restrictions applied during the summer (i.e., mid-phase of fruit growth) led to 24 % water savings with only a 7 % reduction in fruit weight. Fruit cracking was very low in all treatments and seasons (2–6 % over the total quantity fruit collected per tree). Only the RDI regime with restrictions during the summer increased cracking in one out of the three seasons. It is concluded that RDI can be used as a measure to cope with water scarcity and high water prices. Among all the RDI explored, the one with restrictions applied early in the season (during flowering and fruit set) was the most convenient strategy.  相似文献   

17.
The effects of regulated deficit irrigation (RDI) and partial root-zone irrigation (PRI) strategies that apply the same irrigation volumes on vegetative and reproductive development were analyzed during a 3-year-period in field-grown Monastrell grapevines under semiarid conditions. Five treatments were applied: control irrigated at 60?% ETc (crop evapotranspiration) for the whole season (308?mm?year?1); RDI-1 and PRI-1 that received the same irrigation as the control before fruit set, 30?% ETc from fruit set to harvest and 45?% ETc post-harvest (192?mm?year?1); and RDI-2 and PRI-2 that were the same, except with 15?% ETc from fruit set to harvest (142?mm?year?1). Distinctive PRI effects on vegetative and reproductive development were observed depending on the total soil water content and the vine water stress level. PRI-1 vines showed less restriction of vegetative growth, lower leaf abscission, and higher leaf area during post-veraison than RDI-1 vines. Higher supply of water (close to field capacity) via half of the root system in PRI-1 vines maintained better water supply and more favorable phloem sap flow (water and carbohydrates) into the fruit during post-veraison and showed a positive differential effect on fruit growth compared with RDI-1 vines. This was reflected in a higher solute content per berry (12?% higher) and higher fresh berry weight (8?% higher) at harvest in PRI-1 compared to RDI-1 berries. However, this positive effect in fruit growth was not reflected in either an improved final yield or the water use efficiency of PRI-1 vines. In PRI-2, the soil water in the wet half was insufficient to maintain more favorable shoot water supply and phloem sap flow into the berry, and no substantial changes were observed in vine vigor, leaf and fruit growth between PRI-2 and RDI-2. Higher irrigation amount in the wet root zone and higher depth of irrigation under PRI seem to be more effective for 1103P–Mourvedre combination to produce a favorable effect in berry growth and development.  相似文献   

18.
The effect of two deficit irrigation (DI) strategies on fruit and oil production and quality in a 12-year-old ‘Arbequina’ olive orchard with 238 trees ha?1 was evaluated. The T1 treatment was a sustained DI regime (65% ETc, 2–3 irrigation events per week). The T2 treatment was a low-frequency DI (increasing stress/rewatering cycles, which consisted in withholding irrigation until fruit shrivelling and then applying a recovery irrigation providing the same amount of water that supplied in T1 for that period). As compared to full irrigation, both strategies reduced fruit production and increased the variability of fruit ripening, but favoured oil extraction. Free acidity, peroxide value, K232, K270 and sensory quality of oil were not affected by DI. Furthermore, carotenoid, chlorophyll, phenol, and oleic contents increased. The greatest phenol content and bitterness index were found in oil from T2 trees. Later harvesting caused sensory quality and tocopherol losses, although the oil synthesized in DI olives increased.  相似文献   

19.
The effect on productive and vegetative behavior and on the quality of oil from Olea europaea L. when applying two distinct irrigation techniques, full irrigation (FI) and regulated deficit irrigation (RDI), was studied. A total of five wet soil volumes (WSVs, 12, 24, 35, 47 and 59%) expressed in terms of the potential root exploration volume were established for each strategy. The experiment was performed on cv. ‘Arbequina’ in an olive grove in Tarragona (Spain). Results obtained suggest that a 20% reduction in the irrigation dose (RDI) had no significant effect either on olive fruit and oil production or on oil content. Likewise, no significant increase in irrigation water-use efficiency was observed for FI with respect to RDI. A tendency for olive and oil production per hectare to increase with increased WSV percentage was observed, although there were no significant differences between FI and RDI except for 59% WSV in the RDI strategy, producing the best response.  相似文献   

20.
Regulated deficit irrigation (RDI) was applied on field-grown pear-jujube trees in 2005 and 2006 and its effects on crop water-consumption, yield and fruit quality were investigated. Treatments included severe, moderate and low water deficit treatments at bud burst to leafing, flowering to fruit set, fruit growth and fruit maturation stages. Different deficit irrigation levels at different growth stages had significant effects on the fruit yield and quality. Moderate and severe water deficits at bud burst to leafing and fruit maturation stages increased fruit yield by 13.2-31.9% and 9.7-17.5%, respectively. Fruit yield under low water deficit at fruit growth and fruit maturation stages was similar to that of full irrigation (FI) treatment. All water deficit treatments reduced water consumption by 5-18% and saved irrigation water by 13-25% when compared to the FI treatment. During the bud burst to leafing stage, moderate and severe water deficits did not have effect on the fruit quality, but significantly saved irrigation water and increased fruit yield. Low water deficit during the fruit growth stage and low, moderate and severe water deficits during the fruit maturation stage had no significant effect on the fruit weight and fruit volume but reduced fruit water content slightly, which led to much reduced rotten fruit percentage during the post-harvest storage period. Such water deficit treatments also shortened the fruit maturation period by 10-15 d and raised the market price of the fruit. Fruit quality shown as fruit firmness, soluble solid content, sugar/acid ratio and vitamin C (VC) content were all enhanced as a result of deficit irrigation. Our results suggest that RDI should be adopted as a beneficial agricultural practice in the production of pear-jujube fruit.  相似文献   

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