Apricot tree response to withholding irrigation at different phenological periods (original) (raw)
Related papers
Agricultural Water Management, 2014
The effect of different deficit irrigation strategies were studied over a four year period in mature apricot trees (Prunus armeniaca L., cv. Búlida) to ascertain how the intensity and duration of water deficit affects the growth of the root and aerial (shoot, trunk and fruit) parts of the tree, and hence future tree productivity. The irrigation treatments consisted of: a control, irrigated at 100% of seasonal crop evapotranspiration (ETc); continuous deficit irrigation (CDI) at 50% of ETc; two regulated deficit irrigation (RDI), at 100% of ETc only during the critical periods, and reduced to various percentages of ETc during the rest of the season. Soil and plant water status, yield, vegetative and fruit growth were measured in the different treatments. Vegetative growth decreased according to the intensity and duration of the water deficit applied, and depending on the phenological period when the water deficit occurred. Deficit irrigation promoted a decrease in trunk and shoot growth by a 33% on average, although root length density increased nearly double in the 0-0.25 m drip-line band compared with the Control trees. In the RDI treatments, trunk growth and pruning were significantly reduced only under severe water deficit conditions. While CDI proved to be detrimental for maintaining fruit yield due to the significant reduction in vegetative growth, which led to a decrease in the number of fruits per tree, the RDI treatments only led to reduced yields when the water deficits during the non-critical periods were severe, tree trunk growth being significantly reduced as a consequence. Also, fruit size and total yield decreased when deficit irrigation relief was delayed until after the onset of stage III. Overall, water saving up to 22% affected negatively to the total yield and the number of fruits per tree, by reducing the tree growth.
Effects of regulated deficit irrigation on physiology and fruit quality in apricot trees
2010
The effects of regulated deficit irrigation (RDI) were studied on 9 year-old apricot-trees (Prunus armeniaca L. cv. 'Búlida') grafted on 'Real Fino' rootstock. Two irrigation treatments were established. The first, a control treatment, was irrigated to fully satisfy the crop water requirements (100% ETc) and the second, a RDI treatment, was subject to water shortage during the non-critical periods of crop development, by reducing the amount of applied irrigation water to: a) 40% of ETc from flowering until the end of the first stage of fruit growth; b) 60% of ETc during the second stage of fruit growth and c) 50% and 25% of ETc during the late postharvest period (that starts 60 days after harvesting), for the first 30 days and until the end of tree defoliation, respectively. The results indicated that the apricot tree is an appropriate species to apply RDI thanks to the clear separation between their vegetative and reproductive growths and its ability to recover the fruit diameter reduction suffered during RDI application. Furthermore, some qualitative characteristics such as the level of soluble solids, fruit taste and the colour of the fruit are enhanced. These two reasons, together with irrigation water savings of 39%, emphasize the RDI strategies as a possible solution in areas with water shortages, like the southeastern region of Spain.
Irrigation of ‘Hass’ avocado: effects of constant vs. temporary water stress
Irrigation Science, 2019
The main objectives of the present study were to assess the water demand for heavy fruit load of 'Hass' avocado throughout the growth periods and to investigate the effects of deficit irrigation during sensitive phenological phases on yield. The experimental setup allowed the comparison between trees responses to three irrigation strategies during the entire growth period (no water stress; excessive irrigation; constant water stress) as well as the comparison between regulated deficit irrigation (RDI) managements applied during the early or the late growth period. The yield of no water stress treatments during three experimental years was very high (25-31 t ha −1) while the yields of water-stressed trees were significantly lower (16-21 t ha −1). More importantly, the yield of no water stress trees was not susceptible to alternate bearing while the yield of water-stressed trees was considerably reduced during off-crop years. Irrigation rates and the actual evapotranspiration coefficient K L = ET/ET 0 for the no water stress treatment may serve as a reasonable guide for irrigation management. Fruit load should be taken into account while planning irrigation and fertilization management and plant-based methods should be used for controlling the irrigation management (scheduling and quantities). Analyses of trunk diameter variation data that lead to evaluation of trunk growth rate and maximum daily shrinkage reflect phenological stages and periodicity of shoot, fruit and root growth, and also may provide an integrative, "holistic viewpoint" of overall tree status.
Fruits, 2005
Abstract --Introduction. Vegetative and fruit growth in fruit trees are differentially sensitive to water deficit during the season depending on the stage of fruit growth. Attempts have been made to evaluate the possibilities of using regulated deficit irrigation to control vegetative growth and save water in the fruit industry. Materials and methods. Effects of water stress (WS) and crop load (CL) on fruit growth and carbon assimilation rates were evaluated in a 7-year-old 'Elegant Lady' peach orchard. A completely randomized block design with 2 × 3 factors [irrigation with two levels (control and WS) and CL with three levels (light, commercial and heavy)] was used. Results and discussion. Both WS and CL affected fruit growth during the last stages but not early on. CL did not affect trunk water potential which was, however, significantly reduced by WS throughout the day and the season. Trunk water potential of water-stressed trees was lower than that of control trees throughout the day and the season regardless of CL. The magnitude of WS increased as the season progressed. Stomatal conductance, transpiration rate and CO 2 assimilation rate were not affected by CL but were reduced by WS. The trees responded (acclimated) to stress by progressively reducing their transpiration rate as the severity of stress increased. For each irrigation regime, assimilation rates were similar for all three crop levels. This indicated the existence of alternate sinks for assimilates when CL was low, which compensate for the reduction of fruit sink activity resulting from fruit thinning. Conclusion. Water deficit reduced trunk water potential, stomatal conductance, transpiration and photosynthesis in 'Elegant Lady' peach trees. However, CL had a limited effect on these functions. There were good correlations between trunk water potential and either stomatal conductance or assimilation rate in water-stressed trees but not in control trees. This indicates a poor coordination between leaf functions in peach trees under optimal conditions. However, these relationships were stronger under WS conditions. Thus, water use efficiency appeared to increase under water deficit conditions.
International Journal of Physical Sciences, 2011
This study was carried out to investigate effects of different irrigation regimes on fruit pomological properties of drip-irrigated young apricot trees in 2005 and 2008. Six different irrigation treatments were used: five of which (S1, S2, S3, S4, and S5) were based on adjustment coefficients of Class A pan evaporation (0.50, 0.75, 1.00, 1.25, and 1.50). The other treatment (S6) was regulated deficit irrigation treatment that was irrigated by applying 100% of Class A pan evaporation until harvest, but not irrigated after harvest in all the years of study. The effect of different water application levels on fruit weight, fruit diameter, fruit height, seed weight, and flesh / seed ratio was found statistically insignificant. Regression analysis showed that there were significant relations among fruit yield, some quality characteristics, vegetative growth, and evapotranspiration in both 2005 and 2008. Also, the yield per tree and evapotranspiration were related with high R 2 values of 0.97 and 0.76 in 2005 and 2008, respectively. The fruit yield values showed an increasing trend depending on an increase in the tree crown volume, and trunk cross-section area in the experimental years. Fruit quality relationships were different according to the years and quality properties. In 2008, fruit weight reduced while fruit yield increased with fruit diameter and fruit height of more than about 47 and 38 mm, respectively. Thus, it was understood that yield increased, depending on the number of fruit rather than the weight of fruit.
DIFFERENT IRRIGATION INTERVALS AND WATER AMOUNT STUDIES IN YOUNG APRICOT TREES (CV. NINFA
Water shortage studies aiming to provide enough fruit yield and quality by using less water in fruit culture is getting important day by day because of global water scarcity and its negative environmental effects. Hence, this experiment was carried out to investigate the effects of different irrigation intervals and amount treatments on yield and fruit quality of young apricot trees (Prunus armeniaca L. cv Ninfa) during the 2008 and 2009 growing seasons under Mediterranean conditions. Seven, fourteen and twenty-one days irrigation intervals and five irrigation water amounts based on reduction coefficients (Kcp) of class A pan evaporation (0.0, 0.25, 0.50, 0.75 and 1.00) were examined. Pomological variables, such as fruit and seed weights, fruit dimension, flesh firmness, flesh/seed ratio, total soluble solids (TSS), pH and acidity (%), were studied. The interaction between irrigation intervals and the irrigation water amount treatments had significant effects on cumulative yield of the trees. While irrigation water amount had significant effects on all pomological characteristics of fruits, irrigation intervals affected only few fruit quality properties such as fruit weight, flesh firmness, flesh/seed ratio, pH and acidity.
Pear fruit growth under regulated deficit irrigation in container-grown trees
Scientia Horticulturae, 2000
The effect of regulated de®cit irrigation (RDI) on fruit growth was studied for pear trees (Pyrus communis L.`Barlett') grown in 120 l isolated containers. Two irrigation treatments were applied in consecutive seasons (1996 and 1997) but on different trees each year. The Control treatment was watered to non-stress conditions using stem water potential (C stem ) and Penman ETo as a guide for the application of water. The RDI treatment received an average of 15% of the Control applied water from 32 to 60 DAFB (days after full bloom), the latter part of pear fruit development Stage I. Before 32 DAFB and after 60 DAFB, RDI was irrigated as the Control. Tree water status (leaf and stem water potential, leaf conductance and net assimilation rate at midday) and fruit growth parameters were measured periodically during both years. Additionally, in 1997, anatomical measurements of fruit growth (radial distance along fruit cortex tissue, cell number per radial distance and cross-sectional area) were made at the end of the de®cit period and at harvest. Minimal C stem values during the RDI de®cit period were about À1.4 MPa, indicative of moderate stress, and fruit growth was less in RDI than in the Control. The integral of water stress during the de®cit period was linearly correlated with smaller cell size in the fruit cortex, whereas cell number was unaffected. When full irrigation was resumed and during Stage II fruit development, the fruit growth rate remained higher in the Control than in RDI, despite fruit osmotic adjustment and slightly higher tree water status of RDI. At harvest, RDI fruit size was smaller than the Control. The apparent contradiction between these results and studies which report a recovery of fruit growth Scientia Horticulturae 85 (2000) 243±259 : S 0 3 0 4 -4 2 3 8 ( 9 9 ) 0 0 1 5 1 -X after de®cit irrigated period may be caused by differences in growth conditions. #
Response of apricot trees to deficit irrigation strategies
Irrigation Science, 2009
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.
Agricultural Water Management, 2014
Grapefruit (Citrus paradisi Macf.) has increased in importance as a crop species in the southeast of Spain in recent years. In spite of the fact that grapefruit is well adapted to semi-arid conditions, the irrigation necessities for fresh fruit production continue to be very high. The scarcity of water resources forces citrus growers to optimise their water use by using deficit irrigation (DI) strategies. The aim of this work was to evaluate the sensitivity to DI applied during different fruit growth stages of 14-year-old 'Star Ruby' grapefruit grafted on 'Cleopatra' mandarin (Citrus reshni Hort.), regarding water relations, trunk growth, yield and fruit quality. The experiment was carried out over two years in an experimental orchard located in Torre Pacheco (Murcia, southeastern Spain). There were four irrigation treatments; Control (100% crop evapotranspiration-ETc) and three DI treatments (50% ETc) applied only during different fruit growth stages; DI Ph-I (Phase I-cell division), DI Ph-II (Phase II-cell elongation) and DI Ph-III (Phase III-final fruit-growth period, ripening and harvest). The midday stem water potential (« md) values of DI Ph-I and DI Ph-III were influenced by the rainfall regime in both years, whereas the « md of DI Ph-II was decreased and remained lower throughout the study period. Annual trunk growth was reduced only by the DI Ph-I treatment; although the DI Ph-II treatment decreased trunk growth during phase II it was relieved after the recovery period (during phase III). The main effects of both the DI Ph-I and DI Ph-III treatments were related with changes in fruit quality parameters; DI Ph-I reduced the percentage of juice and DI Ph-III affected negatively the peel colour when the water stress was moderate. However, the effects of DI Ph-II were more drastic, decreasing yield due to smaller fruits, altering fruit composition, increasing the titratable acidity much more than the total soluble solids and affecting peel colour, therefore delaying fruit maturation.