Root dynamics of peach trees submitted to partial rootzone drying and continuous deficit irrigation

The root dynamics of young early-season peach trees (Prunus persica L. Batsch, cv. Flordastar) were studied during one growing season. The trees were submitted to three drip irrigation treatments: T1 (control) irrigated at 100% of the estimated crop evapotranspiration (ETc) requirements, T2 (continuous deficit) irrigated at 50% ETc and T3 (partial rootzone drying, PRD, treatment), alternating irrigation from one half to the other every 2–3 weeks. Root length was measured frequently using minirhizotrons and a circular-vision scanner. Overall, root length density was reduced by ≈73% in the continuous deficit irrigated treatment and by ≈42% in the T3 treatment with respect to the well irrigated treatment. A roughly similar amount of water was applied in both deficit irrigated treatments (44 and 56% of T1, for T2 and T3, respectively), but the continuous deficit irrigation applied to both sides of the root system in T2 resulted in a greater reduction in root growth than in T3. The dynamics of the root growth were similar in the three treatments. In general, root growth declined during the fruit growth period and increased after harvest, reaching its peak in mid July. By late July, root growth had declined again, and an alternating pattern of growth between the aerial and root parts of the tree was observed. Roots were mostly located in the upper 0.55 m of soil and were particularly concentrated at 0.40–0.55 m. More than 88% of these roots were very thin, with diameters of <0.5 mm. The study looks at the impact of deficit irrigation on the phenological processes related with root growth, and will help in making decisions concerning fertigation in areas with scarce water resources where deficit irrigation strategies are considered desirable.     

温室番茄节水调质灌水方案评价

为寻求日光温室番茄优质高效的灌溉制度,采用设置于温室番茄冠层齐平位置的水面蒸发测定装置,设计3种基于水面蒸发量的灌水间隔水平和4种灌水量水平组合处理,依据小区试验观测结果,分析确定了以番茄产量、水分利用率、单果重、可溶性固形物质量分数及果实硬度等5项指标为主的节水调质灌溉制度评价体系;在采用变异系数法确定出各指标权重的基础上,借鉴TOPSIS综合评价方法,建立了温室番茄节水、优质、高产相统一的综合评价模型,应用该模型确定基于水面蒸发量的温室番茄节水调质灌溉制度,即当累积水面蒸发量Epan达到10mm±2mm时进行灌溉,灌水量为0.9Epan,在产量不降低的情况下,提高了水分利用率,并在一定程度上提高了果实的营养品质和储运品质.     

Crop root system response to irrigation

Summary In the field, root systems develop in response to both endogenous plant design and soil environment. Downward penetration of root systems results primarily from the growth of monocot axes or of dicot taproots; root proliferation at a given depth results from the growth of laterals at that depth. Root length densities generally decline exponentially with depth under well-watered conditions. Root growth rates are partially controlled by soil conditions. Under irrigation, the most critical soil properties for root growth are oxygen diffusion rate, water content and soil strength and all of these properties are inter-related. Under excess irrigation, especially in heavy soils, root growth may be limited by oxygen diffusion rate. Under limited irrigation, root growth may be limited by lack of water or high soil strength. When irrigation maintains wet surface soils, most of the root system is found in the upper part of the profile where the majority of the water is also taken up.     

温室番茄滴灌灌水指标试验研究

研究了日光温室中番茄的需水量、需水规律、产量与耗水量的关系。对日光温室番茄进行了滴灌灌水制度的研究。根据番茄不同生育期的生理特性及其需水特性确定其相应适宜的土壤含水率范围（占田间持水量的百分比）为：苗期45％～55％，开花坐果期55～75％，坐果期65-85％。不同生育期的灌水定额为：苗期10～15mm，开花坐果期15-25mm，结果期20-30mm。     

Effect of stage-specific saline irrigation on greenhouse tomato production

In many water scarce areas, saline water has been included as an important substitutable resource in agricultural irrigation. It would be of practical use to investigate the effect of stage-specific saline irrigation on yield, fruit quality, and other growth responses of greenhouse tomato, to establish a proper irrigation management strategy for tomato production in these regions. Here, saline irrigations (3.33, 8.33, and 16.67 dS m⁻¹ NaCl solution) were applied during four growth stages of greenhouse tomato (L. esculentum Mill. cv. Zhongza No. 9) grown in the North China Plain, respectively. These include flowering and fruit-bearing stage (stage 1), first cluster fruit expanding stage (stage 2), second cluster fruit expanding stage (stage 3), and harvesting stage (stage 4). Compared with the following three stages, yield loss was most remarkable in stage 1 under all three salinity levels. Under irrigation practices using 3.33 dS m⁻¹ saline water in all four stages, 8.33 dS m⁻¹ saline water in latter three stages, and 16.67 dS m⁻¹ saline water in stage 4, yield reduction was not significant while fruit quality was improved. In conclusion, it is feasible to use stage-specific saline irrigation for tomato production in water scarce areas like North China Plain.     

Cotton response to non-uniformity of conventional sprinkler irrigation

Sprinkler irrigation systems are characterized by some degree of non-uniformity. The effect of non-uniformity on crop yield has been modelled in different ways but experimental studies are scarce. An experiment was conducted comparing the effects of two levels of uniformity (mean Wilkox and Swailes' uniformity coefficients of 80% and 52%) at two levels of water supply (about 400 and 260 mm for the whole irrigation season) on cotton production. Final yield was not affected either by uniformity or by the amount of water supplied. Vegetative growth was higher in the full irrigation treatments. Maximum leaf area index did not differ statistically between uniformity treatments. The lack of differences was attributed to the curvilinear shape of the yield function and to the dampening of the variations in applied water in the soil, as the coefficient of variation in applied water was more than twice the coefficient of variation of infiltrated water. These results suggest that non-uniformity of conventional sprinkler irrigation has a lower impact on cotton crop performance than expected from previous simulation studies. Received: 1 March 1996     

循环曝气地下滴灌的温室番茄生长与品质

循环曝气滴灌可以大幅度提高灌溉水掺气比例,有效改善普通地下滴灌引起的黏质型土壤根区间歇性缺氧环境,提高作物生产力.以河南省中牟县黄河淤积黄黏土为供试土壤,以温室番茄为供试对象,研究循环曝气地下滴灌对番茄生理及品质的影响.结果表明,与普通地下滴灌(对照处理)相比,相同灌溉定额条件下曝气处理番茄果实前5次产量提高了29.15%;番茄的水分利用效率提高了20.72%.曝气处理气孔导度提高了30.51%,植物的生长活力得到增强.番茄果实维生素C含量提高了13.25%,可溶性固形物含量提高了8.62%,糖酸比提高了22.05%,而总酸含量和硬度分别下降了15.50%和11.19%.曝气处理最大根长增加了16.75%,根冠质量之比提高了25.81%.综合分析表明,曝气滴灌可显著促进黄黏土中番茄的生长,促进番茄果实成熟,有效提高作物产量,改善番茄品质.     

A partial root zone drying irrigation strategy for citrus—Effects on water use efficiency and fruit characteristics

In Australian irrigated citriculture, fruit yield and quality outcomes are not tightly related to levels of plant available water, which raises the possibility of using mild water stress applied to part of the root zone, i.e. partial root zone drying, to stimulate physiological mechanisms that reduce tree water use by changing the relationship between stomatal conductance and ambient evaporative conditions.The PRD technique alternates irrigation such that one side of the tree root zone is allowed to dry whilst the other side is irrigated. This significantly reduces the wetted soil volume at any point in time, whilst always maintaining a readily available water supply to part of the root zone. By adopting this irrigation strategy water use of mature Navel orange trees C. sinensis (L.) Osbeck was reduced and water use efficiency was increased. The technique did not induce excessive fruitlet drop and crop yield was unaffected. Both fruit size and juice percentage slightly decreased whereas total soluble solids percentage (TSS) and juice acid percentage increased. As water use was reduced and juice quality attributes were increased, this technique has obvious benefits for juice fruit production.PRD offers an advantage over conventional deficit irrigation strategies because it helps reduce water use by separating the biochemical signaling responses to water deficit in the dry part of the root zone from the physical effects of reduced stomatal conductance due to lower water availability, allowing developmental processes associated with plant growth to remain unperturbed. Irrigating a reduced root zone volume in this way reduces crop water requirement. However, it is also important to understand that this technique pushes the crop to its limits and should only be applied to well established healthy trees.When applying PRD irrigation, it is important that water is supplied with sufficient frequency and depth of wetting to meet the water needs of the whole plant.     

Evapotranspiration and seed yield of field grown soybean under deficit irrigation conditions

Evapotranspiration was measured for a reference crop, rye grass (Lolium prerenne) and soybean (Glycine max L. Merril) grown over two seasons in 2000 and 2001 at Tal Amara Research Station, Lebanon, using drainage and weighing lysimeters. Climatic data from the field weather station were recorded daily. Within the experimental plots, irrigation was withheld at full bloom, R2 stage (S1 treatment), at seed enlargement, R5 stage (S2 treatment) and at mature seeds, R7 stage (S3 treatment). Further, a control (C) was fully-irrigated throughout the growing period.Average crop evapotranspiration (ETc) as measured by the drainage lysimeters in 2000 totaled 800 mm for a total growing period of 140 days. However, when ETc was measured by the weighing lysimeter in 2001, it was 725 mm during a growing period of 138 days. Average crop coefficients (K_c) were computed for different growth stages for the two growing periods by dividing the measured crop evapotranspiration (ETc) by the corresponding measured reference evapotranspiration (ETo-rye grass). K_c values ranged from 0.62 at V10 stage (10th node on the main stem beginning with the unifoliolate node) to 1.0 at pod initiation, then to 0.81 at mature pods.Growth parameters, leaf area index (LAI) and dry matter accumulation, have been shown to be sensitive to water stress caused by the deficit irrigations. However, growth parameters were found to compensate for water stress at early stages, while at seed maturity the compensation ability was decreased.Plants of the lysimeters produced average aboveground biomass and seed yield of 8.1 and 3.5 t ha⁻¹, respectively. However, in the well-irrigated field treatment, aboveground biomass and seed yield averaged 7.3 and 3.2 t ha⁻¹, respectively. Deficit irrigation at R2 stage reduced aboveground biomass and seed yield by 16 and 4%, respectively, while deficit irrigation at R5 stage reduced these two parameters by 6 and 28%, respectively, with comparison to the control. The significant decrease in biomass at R2 stage due to water deficit may be attributed to a pronounced reduction in the number of vegetative nodes. However, limited irrigation at this stage did not reduce significantly (P < 0.01) neither seed number nor seed weight, while at R5 stage these two parameters were reduced by 20 and 10%, respectively, with comparison to the control. Results showed also that deficit irrigation at R7 stage (S3) was more profitable than irrigation deficit at any other crop phenology and did not cause significant reductions either in seed number or seed weight.     

调亏灌溉对大棚滴灌甜瓜生长发育的影响

在大棚滴灌条件下对厚皮甜瓜伊丽莎白不同生育期进行不同程度的亏缺灌溉,研究调亏灌溉对其植株生长、产量、品质及水分利用效率的影响.以土壤相对含水量为标准,在营养生长期和生殖生长期分别设置不同的土壤水分灌溉下限处理,分别是T1(75%~75%),T2(75%~55%),T3(65%~65%),T4(55%~75%),T5(55%~55%)5个试验处理.结果表明:在营养生长期,随着水分亏缺程度的加大,株高、茎粗、叶面积均呈减小趋势.在果实发育阶段,营养生长期及生殖生长期的水分亏缺对果实的生长、产量都有影响,均随亏缺程度的加大而降低,产量以处理T1和T2的最高,T5的最低,T3的大于T4的,各处理间差异具有统计学意义.水分利用效率为处理T2的最高,T1和T4的较低,T2与T4相比,在灌水基本相同的条件下,产量增加了26.2%,水分利用效率提高了27.7%.品质方面,水分亏缺提高了TSS含量;在营养生长期充分灌溉、生殖生长期亏水灌溉可以提高可溶性蛋白、游离氨基酸、维生素C的含量;而营养生长期亏水灌溉、生殖生长期充分灌溉有利于可滴定酸的合成.经综合分析,认为处理T2的灌溉下限设置可以作为武汉地区大棚滴灌条件下的甜瓜灌溉制度.     

Genotypic differences of maize in grain yield response to deficit irrigation

This study was undertaken to investigate genotypic differences of five maize cultivars in grain yield response to two different modes of deficit irrigation, conventional deficit irrigation and partial root zone irrigation. Three irrigation treatments were implemented: (1) FULL irrigation, the control treatment where plant water requirement, 100% Class-A pan evaporation, was fully met and the furrows on both sides of the plant rows were irrigated; (2) partial root zone irrigation (PRI), 35% deficit irrigation, compared to FULL treatment, was applied in every other furrow thus irrigating only one side of the plant rows. The furrows irrigated were alternated every irrigation; (3) conventional deficit irrigation (CDI), the same amount of water as PRI was applied in furrows on both sides of the plant rows, similar to FULL irrigation treatment. Five maize cultivars (P.31.G.98, P.3394, Rx:9292, Tector and Tietar) showing extreme growth response to water stress were selected out of ten cultivars tested with earlier completed greenhouse-pot experiment. A split-plot experimental design, comprising three irrigation treatments and five maize cultivars with four replicates, was used during two years of work, in 2005 and 2006. Total of nine irrigations, with one-week irrigation interval, were annually applied using a drip-irrigation system. Soil water status was monitored using a neutron moisture gauge, in addition to measuring leaf water potential and above-ground biomass production throughout the growing season. Grain yield and other yield attributes were measured at harvest as well as assessing differences in plant root distributions. Decrease in grain yield and harvest index of the tested cultivars, compared to FULL treatment, was proportionally less under PRI than CDI. Whether or not a significant yield advantage can be obtained under PRI compared to CDI showed significant (P < 0.05) genotypic variability. Tector and Tietar among the tested cultivars of maize showed significantly higher grain yield (P < 0.05) under PRI than CDI. The yield advantage of the genotypes (P.3394 and Tector) under PRI compared to CDI seems related to their enhanced root biomass developed under PRI.     

Evaluation of partial root-zone drying for potential field use as a deficit irrigation technique in commercial vineyards according to two different pipeline layouts

The use of partial root-drying (PRD) irrigation implies doubling pipelines instead of using a conventional single pipeline. However, pipelines can be spaced a short distance apart (e.g. 1 m) along the vine row (“D” layout) or joined with cable ties and laid as a single pipeline (“S” layout). Pipelines in “S” configuration are laid under the vine row, and in “D” at both sides of the vine row. These two different layouts can change the wetted soil zone and affect grapevine response to irrigation. The focus of this study was therefore on establishing the role of pipeline layout in vine-grape (cv. ‘Tempranillo’) response under semi-arid conditions in which PRD is managed as a deficit irrigation technique. Six irrigation treatments were applied, which resulted from the combination of Control (C, full irrigation), PRD and seasonal sustained deficit irrigation (SSDI), and “S” and “D” pipeline layouts. SSDI and PRD were irrigated to 50% C throughout the irrigation season, and C irrigation was scheduled according to a crop water balance technique. Midday stem water potential (Ψ_stem) and leaf conductance (g_l) indicated that, on the whole, PRD treatments had a slightly higher water status than SSDI treatments, but a substantially lower status than C treatments. Use of the “D” pipeline layout significantly reduced Ψ_stem in both PRD and SSDI treatments and in some instances for Control conditions, too. Berry yield, vine intercepted radiation, leaf abscisic acid (ABA) and g_l were highly correlated with Ψ_stem. Differences in water status between PRD-S and SSDI-S, according to a sub-surface irrigation test, seemed to be more related to changes in soil evaporation losses and irrigation efficiency than to any intrinsic PRD effect. PRD-S accounted for water savings equivalent to 10% according to the ratio between applied water and grape production for the SSDI-S treatment, whereas PRD-D berry yield was not significantly different from that associated with the SSDI-S treatment. In conclusion, under the growing conditions of this experiment, PRD-S offered the possibility of slightly improving water conservation when irrigation was applied to the soil surface.     

Almond agronomic response to long-term deficit irrigation applied since orchard establishment

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% ET_c); (ii) RDI, as FI but receiving 40% ET_c during kernel-filling; (iii) mild-to-moderate SDI (SDI_mm), irrigated at 75–60% ET_c over the entire growing season; and (iv) moderate-to-severe SDI (SDI_ms), irrigated at 60–30% ET_c 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. SDI_ms increased IWP by 92.5%, reduced yield by 29% and applied 63% less irrigation water. RDI and SDI_mm showed similar productive performances, but RDI was more efficient than SDI_mm to increase fruiting density and production efficiency (PE). We conclude that SDI_ms appears to be a promising DI option for arid regions with severe water scarcity, whereas for less water-scarce areas RDI and SDI_mm behaved similarly, except for the ability of RDI to more severely restrict vegetative development while increasing PE.     

Peach tree response to single and combined deficit irrigation regimes in deep soils

The response of mature ‘Andross’ cling peach (Prunus persica L. Batch) trees to regulated deficit irrigation in deep soils was studied for 3 years. Trees were either fully irrigated or subjected to deficit irrigation during Stage II of fruit development and/or during post-harvest. Single regulated deficit irrigation regimes reduced irrigation by 13–24%, while combined regime reduced it by 23–35%. Deficit irrigation during Stage II and/or post-harvest significantly reduced vegetative growth of the trees. Fruit production was not affected by any irrigation regime until the fourth year when fruit set decreased slightly with combined deficit irrigation. Overall, the results indicate that regulated deficit irrigation can be used successfully on peach trees grown in deep soils.     

Yield and quality of melon grown under different irrigation and nitrogen rates

During 2 years, a melon crop (Cucumis melo L. cv. Sancho) was grown under field conditions to investigate the effects of different nitrogen (N) and irrigation (I) levels on fruit yield, fruit quality, irrigation water use efficiency (IWUE) and nitrogen applied efficiency (NAE). The statistical design was a split-plot with four replications, where irrigation was the main factor of variation and N was the secondary factor. In 2005, irrigation treatments consisted of applying daily a moderate water stress equivalent to 75% of ETc (crop evapotranspiration), a 100% ETc control and an excess irrigation of 125% ETc (designated as I₇₅, I₁₀₀ and I₁₂₅), while the N treatments were 30, 85, 112 and 139 kg N ha⁻¹ (designated as N₃₀, N₈₅, N₁₁₂ and N₁₃₉). In 2006, both the irrigation and N treatments applied were: 60, 100 and 140% ETc (I₆₀, I₁₀₀ and I₁₄₀) and 93, 243 and 393 kg N ha⁻¹ (N₉₃, N₂₄₃ and N₃₉₃). Moderate water stress did not reduce melon yield and high IWUE was obtained. Under severe deficit irrigation, the yield was reduced by 22% mainly due to decrease fruit weight. The relative yield (yield/maximum yield) was higher than 95% when the irrigation depth applied was in the range of 87-136% ETc. In 2006, the interaction between irrigation and N was significant for yield, fruit weight and IWUE. The best yield, 41.3 Mg ha⁻¹, was obtained with 100% ETc at N₉₃. The flesh firmness and the placenta and seeds weight increased when the irrigation level was reduced by 60% ETc. The highest NAE was obtained with quantities of water close to 100% ETc and increased as the N level was reduced. The highest IWUE was obtained with applications close to 90 kg N ha⁻¹. The I₂₄₃ and I₃₉₃ treatments produced inferior fruits due to higher skin ratios and lower flesh ratios. These results suggest that it is possible to apply moderate deficit irrigation, around 90% ETc, and reduce nitrogen input to 90 kg ha⁻¹ without lessening quality and yields.     

Responses of ‘Petopride’ processing tomato to partial rootzone drying at different phenological stages

Partial rootzone drying (PRD) is a water-saving irrigation practice which involves watering only part of the rhizosphere at each irrigation with the complement left to dry to a pre-determined level. The effect of PRD, applied at different phenological stages, on yield, fruit growth, and quality of the processing tomato cv. ‘Petopride’ was studied in this experiment. The treatments were: daily full irrigation (FI) on both sides of the root system considered as the control, and PRD treatments applied at three phenological stages. These were: during the vegetative stage until the first truss was observed (PRD_VS–FT), from the first truss to fruit set (PRD_FT–FS), and from fruit set to harvest (PRD_FS–H). In some occasions, leaf xylem water potential was lower in each PRD period than in FI. Number of fruits, total fresh and dry weight of fruit per plant, harvest index, and fruit growth were lower in PRD_FT–FS and PRD_FS–H plants than in FI and PRD_VS–FT plants. However, irrigation water use efficiency, on a dry weight basis, was the same among the treatments. For PRD_FT–FS and PRD_FS–H treatments, mean fresh weight of fruit and fruit water content were reduced and dry matter concentration of cortex and total soluble solids concentration of fruit increased compared with FI and PRD_VS–FT treatments. Incidence of blossom-end rot was the same among PRD_VS–FT, PRD_FS–FH, and FI fruit, but it was higher in PRD_FT–FS fruit. Fruit skin colour was the same among treatments. Total dry weight of fruit per plant decreased by 23% for PRD_FT–FS and by 20% for PRD_FS–H relative to FI. Fruit quality improvement in PRD_FS–H could compensate for the reduction in total dry weight of fruit where water is expensive for tomato production. But an economical analysis would be needed to substantiate this. PRD from the first truss to fruit set is not recommended because of the high incidence of blossom-end rot. An erratum to this article can be found at     

温室滴灌条件下番茄植株茎流变化规律试验

为探明滴灌条件下温室番茄植株茎流速率变化规律及其影响因素,本文采用Dynamax公司开发的包裹式茎流计观测日光温室番茄植株的茎流变化,研究茎流速率的变化规律及茎流速率监测结果的标准化处理技术,探索植株茎流与气象因子的相互关系,分析水分胁迫对番茄植株茎流速率的影响。研究表明,采用单位叶面积上的茎流速率表征茎流变化规律可在一定程度上降低因探头安装位置不同对监测结果的影响;在充分供水条件下,影响番茄植株茎流速率的主要因子是太阳辐射和饱和水气压差,番茄植株的日茎流速率与太阳辐射呈线性关系,与饱和差呈对数关系（R2＞0.90,P＜0.01）;土壤水分状况会明显影响番茄植株茎流状况,茎流速率随水分胁迫加剧而骤减。研究结果证明番茄植株茎流速率经标准化处理后可以真实的反映植株蒸腾规律。     

Oxyfertigation of a greenhouse tomato crop grown on rockwool slabs and irrigated with treated wastewater: Oxygen content dynamics and crop response

This work assesses the seasonal dynamics of the substrate oxygen content and the response to nutrient solution oxygen enrichment (oxyfertigation) of an autumn-spring tomato crop grown on rockwool slabs and irrigated with treated wastewater of very low dissolved oxygen (DO) content under Mediterranean greenhouse conditions. DO values in the nutrient solution were clearly higher for the oxygen-enriched (14.6 mg L⁻¹) tomato crop than for the non-enriched one (4.5 mg L⁻¹). However, DO values in the substrate solution were similar for both oxygen treatments (mean seasonal values of 5.1 and 4.8 mg L⁻¹ for the enriched and the non-enriched one, respectively), except for a short crop period at the end of the cycle when they were significantly higher for the oxygen-enriched crop. For both treatments, substrate DO values were highest for the winter period and decreased progressively during the spring period, reaching minimum values of around or below 3 mg L⁻¹ at the end of the spring. The oxygen enrichment of the nutrient solution did not affect any of the irrigation and fertigation parameters evaluated in the tomato crop: water uptake, volumetric water content of the substrate, electrical conductivity (EC) or nutrient concentration in the leached nutrient solution. Moreover, the oxygen enrichment of the nutrient solution did not affect the aboveground biomass and the biomass partitioning, the fresh weight of total and marketable tomato fruits or the tomato fruit quality parameters. Overall, it appears that oxygen deficiency conditions did not occur as the substrate DO values were higher than, or about, 3 mg L⁻¹ throughout most of the tomato crop cycle for both treatments and the rockwool slabs maintained good aeration conditions throughout the whole cycle.     

Partial rootzone drying and deficit irrigation of ‘Fuji’ apples in a semi-arid climate

The effects of deficit irrigation (DI) and partial rootzone drying (PRD) on apple (Malus domestica Borkh. Cv. ‘Fuji’) yield, fruit size, and quality were evaluated from 2001 to 2003 in the semi-arid climate of Washington State. PRD and DI were applied from about 40 days after full bloom until just before (2001, 2002) or after (2003) harvest and compared to a control irrigation (CI). Irrigation was applied once a week using two micro-sprinklers per tree. Soil-water content in CI was maintained above 80% of field capacity using micro-sprinklers on both sides of a tree. The DI and PRD were irrigated at about 50% (2001–2002) and 60% (2003) of the CI, but differed in placement of irrigation. For DI both micro-sprinklers were operated whereas PRD was irrigated using only one micro-sprinkler wetting half the rootzone compared to CI and DI. Wetting/drying sides of PRD trees were alternated every 2–4 weeks (2001, 2002) or when soil-water content on the drying side had reached a threshold value (2003). Seasonal (1 May–31 October) potential evapotranspiration (ET₀) was 967, 1002, and 1005 mm for 2001, 2002, and 2003, and rainfall totaled 58, 39, and 21 mm, respectively. Irrigation amounts applied were 596, 839, and 685 mm in the CI; 374, 763, and 575 mm in the DI; and 337, 684, and 513 mm in the PRD for the 2001, 2002, and 2003 seasons. Higher irrigation volumes in 2002 were due to excessive (177–324 mm) irrigations after harvest. No significant differences were found in yield and fruit size among treatments in 2001 and 2003. In 2002, DI had significantly lower yield than CI, while the yield of PRD did not differ from CI and DI. Fruit from DI and PRD were firmer and had higher concentrations of soluble solids than fruit from CI, both at harvest and following short-term storage at 20°C, but differences to CI were significant in 2002 only. Treatment effects on fruit titratable acidity were inconsistent. Additional water was preserved in the soil profile under PRD compared to DI in 2001 and 2003, but no statistical differences were found between PRD and DI in 2002. Approximately 45–50% of irrigation water was saved by implementing newly developed DI and PRD irrigation strategies without any significant impact on fruit yield and size with PRD. However, apple yield was reduced by DI compared to CI in the second year.