Search results for "Stem water potential"
showing 10 items of 18 documents
Agro-hydrological models and field measurements to assess the water status of a citrus orchard irrigated with micro-sprinkler and subsurface drip sys…
2021
Compared to the micro-sprinkler irrigation, traditionally used in citrus orchards, subsurface drip systems (SDS) allow increasing the water use efficiency (WUE); when coupled with water-saving strategies, like regulated deficit irrigation (RDI), further increase of WUE are possible. Combining measurements of soil water content (SWC) and weather data with measurements of midday stem water potential (MSWP) makes it possible to identify irrigation scheduling parameters for the RDI. However, measurements of MSWP are destructive and time-consuming, and also require skilled operators. For all these reasons, the use of the agro-hydrological models, such as the FAO-56 model, can be considered a sur…
Water status and gas exchange of pistachio trees under different irrigation levels
2017
The aim of this study was to investigate the physiological responses of pistachio trees to varying water supply in the attempt to identify reliable parameters to manage irrigation. Three different irrigation regimes were applied to 25-year-old pistachio trees of cultivar 'Bianca' on P. terebinthus rootstock. Midday stem water potential (ΨSWP), leaf relative water content (RWC), light-saturated net CO2assimilation (An), stomatal conductance (gs), and ambient conditions were monitored throughout the season, and light response curves of net photosynthesis were constructed. To reflect tree water status, trees were separated into three classes of ΨSWP, no deficit (ΨSWP> -1.5 MPa), mild defici…
Sustainability of pistachio production (Pistacia vera L.) under supplemental irrigation in a Mediterranean climate
2018
Abstract The objective of this study was to examine the effects of supplemental micro-irrigation, in a commercial rainfed orchard, on tree water status, gas exchange and productivity of Pistacia vera L. (cv Bianca) grafted on P. terebinthus. Irrigating with 10–15% of estimated full evaporative demand significantly increased average annual productivity by increasing yield in the on-crop year of this alternate bearing species. Irrigation increased yield by 30%, resulting in 1600 kg of in-shell product per ha. Irrigation delayed leaf senescence while flower bud abscission was not reduced until the third year of experiment. Irrigation did not improve gas exchange during Stage I (pericarp growth…
Water Deficit Affects the Growth and Leaf Metabolite Composition of Young Loquat Plants
2020
Water scarcity in the Mediterranean area is very common and understanding responses to drought is important for loquat management and production. The objective of this study was to evaluate the effect of drought on the growth and metabolism of loquat. Ninety two-year-old plants of &lsquo
GROWTH AND BIOMASS PARTITIONING OF YOUNG LOQUAT PLANTS UNDER WATER DEFICIT
2015
Water scarcity in the Mediterranean areas is very common and understanding responses to drought is important for loquat management and production. The objective of this study was to evaluate the effect of water deficit on growth and biomass partitioning of loquat. Ninety 1-year-old plants of 'Marchetto' loquat (Eriobotrya japonica Lindl.) grafted on quince were grown in the greenhouse in 12-liter pots and three water regimes were imposed starting on 11 May and until 27 July, 2013. One-third of the plants was irrigated to reintegrate 100% of the water consumed (CTR); a second group of plants was irrigated with 66% of the water consumed by CTR plants (MD); a third group was irrigated with 33%…
Improvement of FAO-56 Model to Estimate Transpiration Fluxes of Drought Tolerant Crops under Soil Water Deficit: Application for Olive Groves
2014
[EN] Agro-hydrological models are considered an economic and simple tool for quantifying crop water requirements. In the last two decades, agro-hydrological physically based models have been developed to simulate mass and energy exchange processes in the soil-plant-atmosphere system. Although very reliable, because of the high number of required variables, simplified models have been proposed to quantify crop water consumes. The main aim of this paper is to propose an amendment of the Food and Agricultural Organization (FAO) of the United Nations FAO-56 spreadsheet program to introduce a more realistic shape of the stress function, valid for mature olive orchards (Olea europaea L.). The mod…
Relationship between tree water status and physiology, yield, and fruit quality in the table olive (Olea europaea sativa L.) cultivar ‘Nocellara del …
2012
Although the olive (Olea europaea sativa l.) is considered a xerophytic species, long periods of water stress and high temperatures during summer months can greatly affect plant physiology and productivity. In recent years, the use of plant-based water status indicators have become popular in the study of plant-water relationships and in the design of irrigation programs, particularly midday stem water potential (ψstem). The current trend in the irrigation of olive trees is in the development of Deficit Irrigation (DI) systems whereby the water is applied at a rate which is lower than evapotranspiration needs, resulting in only very small reductions in yield. Rather than working towards min…
Modelling eco-physiological response of table olive trees (Olea europaea L.) to soil water deficit conditions
2013
Abstract The knowledge of crop response to water stress is crucial to predict transpiration reductions under limited soil water conditions and for a rational scheduling of irrigation. In order to assess whatever water stress model, it is necessary to estimate critical thresholds of soil water status, below which plant transpiration starts to decrease. The main objective of the work is to identify the shape and to determine the parameters of table olive orchards (Olea europaea, var. Nocellara del Belice) water stress function, assessed according to relative transpiration or leaf/stem water potential. In order to assess different water stress functions describing the eco-physiological field r…
Detecting Mild Water Stress in Olive with Multiple Plant-Based Continuous Sensors.
2021
A comprehensive characterization of water stress is needed for the development of automated irrigation protocols aiming to increase olive orchard environmental and economical sustainability. The main aim of this study is to determine whether a combination of continuous leaf turgor, fruit growth, and sap flow responses improves the detection of mild water stress in two olive cultivars characterized by different responses to water stress. The sensitivity of the tested indicators to mild stress depended on the main mechanisms that each cultivar uses to cope with water deficit. One cultivar showed pronounced day to day changes in leaf turgor and fruit relative growth rate in response to water w…
Growth and physiological responses of young olive trees affected by Olive leaf yellowing associated virus
2017
We studied the effect of Olive leaf yellowing associated virus (OLYaV) on biometric and physiological changes in olive. The trial was carried out on 32 two-yearold virus-free trees of 'Frantoio' grafted on virus-free olive seedlings and grown in 32-L pots. Half of the trees were inoculated with OLYaV in the fall of 2007. At 6, 18, and 24 months after inoculation, tree height, basal trunk diameter and total leaf number were determined, and leaf area tree-1 was estimated from a 50-leaf subsample. Twigs of various order were also counted and measured. At the end of the experiment, dry matter partitioning, leaf gas exchange and water potential were also measured. Total twig length and number, t…