Regulated deficit irrigation in table olive trees during a sensitive period

Olive tree is one of the most important irrigated fruit at Spain (around 400.000 ha). The water needs in olive orchard are greater than the water availability. Therefore, deficit conditions are common at the field. The aim of this work is to study a regulated deficit irrigation (RDI) scheduling based on midday stem water potential (Y) that limits irrigation before harvest. The experiment was performed at La Hampa experimental farm (Coria del río, Seville, Spain) in 45 years-old olive (cv Manzanillo). Three irrigation treatments in a complete randomized block design were performed during 2014.This research was supported by the Spanish Ministerio de Economía y Competitividad (MINECO), (AGL2013-45922-C2-1-R).Peer Reviewe

Limitations and usefulness of maximum daily shrinkage (MDS) and trunk growth rate (TGR) indicators in the irrigation scheduling of table olive trees

8 páginas.-- 7 figuras.-- 2 tablas.-- 32 referenciasMaximum daily trunk shrinkage (MDS) is the most popular indicator derived from trunk diameter fluctuations in most fruit trees and has been reported to be one of the earliest signs in the detection of water stress. However, in some species such as olive trees (. Olea europaea L.), MDS does not usually change in water stress conditions and trunk growth rate (TGR) has been suggested as better indicator. Most of this lack of sensitivity to drought conditions has been related to the relationship between the MDS and the water potential. This curvilinear relationship produces an uncertain zone were great variations of water potential do not imply any changes of MDS. The MDS signal, the ratio between measured MDS and estimated MDS with full irrigation, has been thought to be a better indicator than MDS, as it reduces the effect of the environment. On the other hand, though literature results suggest an effect of environment in TGR values, there are not clear relationship between this indicator and meteorological data. The aims of this work are, on one hand, to study the improvements of the baseline approach in the MDS signal and, on the other, study the influence of several meteorological variables in TGR. Three years' data from an irrigation experiment were used in to carry out the MDS analysis and six years' data for full irrigated trees during pit hardening period were used for TGR study. The comparison between MDS vs. water potential and MDS signal vs. water potential presented a great scattering in both relationships. Values of MDS signal between 1.1 and 1.4 were always identified with moderate water stress conditions (-1.4 to -2. MPa of water potential). However, since this MDS signal values are around the maximum in the curvilineal relationship with water potential, greater values of MDS signal (in the range of 1.1-1.4) were not necessary lower values of water potential. In addition, during low fruit load seasons MDS signal was not an accurate indicator. On the other hand, absolute values of several climatological measurements were not significantly related with TGR. Only daily increments explain part of the variations of TGR in full irrigated trees. In all the data analysed, the daily increment of average vapour pressure deficit was the best indicator related with TGR. The increase of this indicator decreased TGR values. In addition, the agreement between this indicator and TGR was affected for fruit load. Great yield seasons decrease the influence of VPD increment in TGR.This research was supported by the Spanish Ministerio de Ciencia e Innovación (MICINN), (AGL2010-19201-CO4-03). Thanks are due to J. Rodriguez and A. Montero for help with field measurements.Peer reviewe

Fruit water relations as a tool to reduce fruit physiopathies incidence and to increase fruit quality

5 páginas.-- 24 referencias.-- Comunicación presentado en el XIV Simposio Internacional Hispano-Portugués de Relaciones Hídricas en Plantas de la Sociedad Española y Portuguesa de Fisiología Vegetal.“La fisiología como valor añadido para la comercialización”Galindo Egea, A. et al....In this communication the effect of water deficit on fruits is discussed. The incidence of some pre- and post-harvest fruit physiological disorders related to water stress are also considered. Current knowledge of water flow in developing fruits, fruit water relations under drought and the effect of water deficit on fruit quality characteristics, mainly those related to human health are also discussed.Peer Reviewe

Feasibility of trunk diameter fluctuations in the scheduling of regulated deficit irrigation for table olive trees without reference trees

12 páginas.-- 10 figuras.-- 4 tablas.-- 43 referencias.--Regulated deficit irrigation (RDI) results are affected by the actual water stress level reached during the treatments. The irrigation scheduling based on water status measurements, such as trunk diameter fluctuations, can control in an accurate way the water restrictions. However, the number of works that use these indicators as isolate parameter to control the schedule is scarce in general, and very scarce in olive trees. Building on previous works, the aim of this article is to schedule an RDI strategy in olive trees based on threshold values of maximum daily shrinkage (MDS) and trunk growth rate (TGR) without reference trees. The experiment was performed in a 40 years-old table olive orchard (cv Manzanillo) in Seville (Spain) for 3 years (seasons from 2011 to 2013). Three different irrigation treatments were considered in a completely randomized block design. Control trees were over-irrigated (125% crop evapotranspiration, ETc) in order to obtain fully irrigated conditions. Water stress conditions were applied during Phase II (pit hardening) in the RDI-2 treatment or during Phase II and Phase I (full bloom) in RDI-12. In both RDIs, a treatment recovery (Phase III) was performed before harvest. The trunk diameter fluctuation indicator was selected according to the phenological stage. TGR was used in conditions of full irrigation or moderate water stress level, such as Phase I and Phase III. TGR threshold values based on previous works were selected: 20 mday−1, RDI-2; 10 mday−1, RDI-12 (Phase I) and −5 mday−1, both treatments, Phase III. Only in one season RDI-2 was scheduled with TGR values (−10 mday−1) during Phase II. MDS threshold values were determined as the ratio between measured MDS and fully irrigated MDS (the so called MDS signal). The latter was estimated from a baseline. During Phase II, RDI-2 was irrigated with a threshold value of 0.9, while RDI-12 was irrigated with a threshold value of 0.75. MDS signal was not useful for most of the period considered and it did not agree well with fruit drop or fruit size. Conversely, the average of TGR during Phase II was significantly linked to fruit drop and fruit size, and so were the midday stem water potential and stress integral. Recommendations about the management of TGR are discussed. The water stress level in the experiments was moderate and no significant differences in yield were found. However, the trend of yield reduction in RDI-12 was likely related with a fruit drop and a reduction in crown volume. The yield quality did not decrease in the RDIs treatments, on the contrary, pulp:stone ratio improved significantly in some of the seasons.This research was supported by the Spanish Ministerio de Ciencia e Innovación (MICINN), (AGL2010-19201-CO4-03 and AGL2013-45922-C2-1-R). Thanks are due to J. Rodriguez and A. Montero for help with field measurements.Peer reviewe

Comparison of the water potential baseline in different locations. Usefulness for irrigation scheduling of olive orchards

9 páginas.-- 5 figuras.-- 8 tablas.-- 31 referencias.-- Corell, M. et al. (2016) Comparison of the water potential baseline in different locations. Usefulness for irrigation scheduling of olive orchards. Agricultural Water Management (177) 308-316Deficit irrigation scheduling needs accurate indicators and in recent decades, continuous plant indicators have been developed. However, threshold values that could be useful in commercial orchards are not commonly reported. The water potential is a discontinuous measurement commonly used as a reference in the description of water stress level. In some fruit trees, such as olive trees, there are several works suggesting threshold values in fully irrigated conditions, but the influence of the evaporative demand is not taken into account. The aim of this work is to compare the values of the fully irrigated water potential in different locations in order to study the estimation of a common baseline. Three mature olive orchards were selected, two in Seville (South Spain) and one in Ciudad Real (Central Spain). There were clear differences between the three orchards during the 2015 season. Orchards in Seville (S-1 and S-2) were close (10 km apart) and had the same cultivar (table olive, cv Manzanilla) but they were different in terms of the fruit load (almost no fruit in S-1, medium fruit load in S-2) and distribution of water (single drip line in S-1, double drip line in S-2). The orchard in Ciudad Real (CR) was very different with regards to the olive cultivar (cv Cornicabra) and the location, as it was in a borderline zone for olives growing with very low temperatures that delay the phenological development. In all the orchards, the best baseline was obtained with different climatic measurements, even in S-1 and S-2. When all the data were considered, the best fit was obtained with the average vapour pressure deficit (VPDav). Influence of the location was significant in the interception term of the equations when Temperature was used but not with VPD. This source of variation was reltade with the level of fruit load. Slope of the equations was not affected for the location. The equation obtained was validated with water potential data from previous seasons of S-1 and CR orchards. Maximum temperature presented the best validation results. The usefulness of this baseline is discussedThis research was supported by the Spanish Ministerio de Ciencia e Innovación (MICINN), (AGL2013-45922-C2-1-R).Peer reviewe

Effect of deficit irrigation and elaboration process of spanish-style green table olives on phytoprostanes content in Manzanilla de Sevilla olive flesh

5 páginas.-- 4 tablas.-- 6 referencias.-- Comunicación oral presentada en el XII Luso-Spanish Symposium on Plant Water Relations – Water to Feed the World. 30th of September – 3rd of October (Evora) PortugalManzanilla de Sevilla olive trees were summited to three different irrigation treatments. Control (T0) trees were over-irrigated (125 % ETc) and T1 and T2 trees were submitted to regulated deficit irrigation (RDI) according to trunk diameter fluctuations data with a pronounced irrigation water restriction during pit hardening. Seasonal water amounts received by each treatment, without considering precipitation, were 412, 130 and 111 mm in 2012 and 369, 207 and 106 mm in 2013 for T0, T1 and T2 treatments, respectively. Olive yield and fruit size were not affected by deficit irrigation during olive pit hardening. However, this phenological period was critical for olive flesh composition in just harvested and processed olives. Stress integral was better indicator than minimum midday stem water potential for predicting the PhytoPs content, pointing to the idea that the increase in PhytoPs depends in a greater extension of the length of water stress instead of maximum stress achieved. The results suggested that the olive fruit processing enhance the accumulation of total PhytoPs, but decrease the number of these chemical compounds. Consequently, olive table tree culture under deficit irrigation conditions during pit hardening and the processing of its fruits to obtain Spanish-style olives can be considered as complementary actions to enhancing the PhytoP content and hence their potential beneficial effects on human health.To R. Pleites and Global Olive and Cooperativa Nuestra Señora de las Virtudes for the management of the industrial processing. This research was supported by MICINN (CICYT/FEDER AGL2013-45922-C2-1-R and AGL2013-45922-C2-2-R) CSIC 201170E041, Fundación Séneca (04486/GERM/06) and CYTED, Action 112RT0460 CORNUCOPIA grants to the authors. JCG and AG were funded by a grant of the FPI and FPU fellowship program, respectively, and SM was appointed under a CSIC research contract.Peer Reviewe

Water stress at the end of the pomegranate fruit ripening stage produces earlier harvest and improves fruit quality

páginas.-- figuras.-- tablas.-- 47 referencias.- Galindo, A. et al... Scientia Horticulturae, 226: 68-74 (2017) DOI: 10.1016/j.scienta.2017.08.029Pomegranate (Punica granatum L.) is a drought tolerant crop, which thrives in the face of scarce water resources, this fact underlines the importance of determining the optimum harvest time to improve the quality of pomegranate fruits. This research was focused on the crop responses to drought stress during the phenological period of fruit ripening. Special attention was paid to the effects on plant productivity of water restrictions during fruit ripening and whether such restrictions have secondary effects on fruit characteristics and composition. Control plants were irrigated above crop water requirements while deficit irrigation treatments were irrigated as control plants except for 6 days (fruit late ripening), 15 days (second half fruit ripening), 25 days (fruit ripening), and 36 days (end fruit growth and late ripening) before harvest, when irrigation was withheld. The results indicated that the water stress integral, calculated from leaf conductance, leaf water potential, stem water potential and fruit water potential data, differed in their assessment of the cumulative water deficit reached by the plants. Also, pomegranate fruit ripening was confirmed as a critical period because irrigation is clearly essential during most of this phenological period to achieve maximum yield. Moreover, a very short period of irrigation restriction (around 6 days) at the end of ripening period comes early harvest time, saves irrigation water, enhances the bioactive compounds content (anthocyanins, phenolic compounds, punicalagin and ellagic acid) and increases the price of the fruit without affecting marketable yield and fruit size. This suggests that the sensitivity to water stress during such a critical phenological period is not constant and/or that for productivity to be adversely affected it is necessary to exceed a threshold level of water stressThis research was supported by Ministerio de Economía y Competitividad (MINECO) (CICYT/FEDERAGL2013-45922-C2-1-R and AGL2013-45922-C2-2-R) grants to the authors. Also, this work is a result of the PR internship (19925/IV/15) funded by the Fundación Séneca − Agencia de Ciencia y Tecnología de la Región de Murcia (Seneca Foundation − Agency for Science and Technology in the Region of Murcia) under the Jiménez de la Espada Program for Mobility, Cooperation and Internationalization. AG and ZNC were funded by a postdoctoral financial support received from the Ramón Areces Foundation program and AECID grant from the Spanish Government, respectively.Peer reviewe

Regulated deficit irrigation on table olive based on midday stem water potential during a sensitive phenological stage

Peer Reviewe

Using band dendrometers in irrigation scheduling. Influence of the location inside the tree and comparison with point dendrometer

8 páginas.-- 8 figuras.-- 3 tablas.-- 47 referencias.-- 4 figuras en Supplementary material related to this article can be found,in the online version, at http://dx.doi.org/10.1016/j.agwat.2014.04.005Trunk diameter fluctuation parameters have been common indicators in water relations experiments. In most fruit trees, these parameters have been reported as very sensitive to drought conditions. However, the great variability of the measurements, amongst other factors, has limited their use in commercial orchards. One of the sources of error could be the location of the sensors on the tree, which has been poorly studied. In addition, almost all the studies in horticultural science have been performed with point dendrometers, while in forest research band and point dendrometers have been used. The aims of this work were (i) evaluate the influence of band dendrometers location on mature olive trees (branch or trunk, experiment 2011, and (ii) compare the feasibility of them with point dendrometers (experiment 2012). Wireless Sensor Network band dendrometers were installed in 5 trees during 2011 in the main trunk and in branches. Trunk growth rate (TGR) and maximum daily shrinkage (MDS) were compared in both locations. Individual TGR data of these trees were all around the line 1:1 in the relationship between trunk and branch. Individual MDS data in stressed trees were significantly higher than the line 1:1 in the branch vs trunk relationship. The non-stressed MDS data, however, were not significantly different to this line. During 2012, band and point dendrometers were installed in the main trunk of 3 trees. The location did not affect the values of the indicators in non-stress conditions, but significant changes were found in MDS of stressed trees. The relationship between band and point dendrometer was probably affected by the variability of the trunk itself.AcknowledgementsThis research was supported by the Spanish Ministerio de Cien-cia e Innovación (MICINN), (AGL2010-19201-CO4 subprojects 01,03 and 04.)Peer reviewe

Deficit irrigation and emerging fruit crops as a strategy to save water in Mediterranean semiarid agrosystems

14 páginas.-- 4 figuras.-- 3 tablas.-- 147 referencias.-- : Galindo,A., et al...Water scarcity in Mediterranean climate areas will be progressively aggravated by climate change, population increase and urban, tourism and industrial activities. To protect water resources and their integrity for future use and to improve biodiversity, besides following advanced deficit irrigation strategies in fruit cultivation, attention could well be directed towards what are at present underused plant materials able to withstand deficit irrigation with minimum impact on yield and fruit quality. To this end, the state of the art as regards deficit irrigation strategies and the response of some very interesting emerging fruit crops [jujube (Zizyphus jujuba Mill.), loquat (Eriobotrya japonica Lindl.), pistachio (Pistacia vera L.) and pomegranate (Punica granatum L.)] are reviewed. The strengths and weaknesses of deficit irrigation strategies and the mechanisms developed by these emerging fruit crops in the face of water stress are discussed. The response of these crops to deficit irrigation, with special attention paid to the effect on yield but also on fruit quality and health-related chemical compounds, was analysed in order to assess their suitability for saving water in Mediterranean semiarid agrosystems and to analyze their potential role as alternatives to currently cultivated fruit crops with higher water requirements. Finally, the factors involved in establishing an identity brand (hydroSOS) to protect fruits obtained under specific DI conditions are discussed.We are also grateful to the Ministerio de Economía y Competitividad de España (MINECO) (CICYT/FEDER AGL2013-45922-C2-1-R, AGL2013-45922-C2-2-R, AGL2016-75794-C4-1-R and AGL2016-75794-C4-4-R) for grants to the authors. AG and JC-G acknowledge the postdoctoral financial support received from the Ramón Areces Fondation and the Juan de la Cierva program, respectively. Also, this work is a result of the PR internship (19925/IV/15) funded by the Fundación Séneca – Agencia de Ciencia y Tecnología de la Región de Murcia (Seneca Foundation – Agency for Science and Technology in the Region of Murcia) under the Jiménez de la Espada Program for Mobility, Cooperation and Internationalization.Peer reviewe