Search results for " Stem Water Potential"
showing 10 items of 10 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…
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…
Plant-based water stress sensing in two olive cultivars with different physiological responses to drought
2022
A large portion of modern olive plantings is dominated by one main cultivar (‘Arbequina’) planted at super high density (SHD, 1,500 tree ha‑1), leading to a dangerous reduction in olive biodiversity. Very few cultivars have growth and productive patterns that suit the SHD system requirements. Partial intensification and mechanization with several cultivars may represent the safest and easiest alternative. The efficient use of limited natural resources, such as water, in SHD systems, requires precise management. Continuous plant-based sensing is a promising approach to managing water, mainly tested on the cultivar ‘Arbequina’. In this study, we evaluated the sensitivity of two promising indi…
Soil and Regulated Deficit Irrigation Affect Growth, Yield and Quality of ‘Nero d’Avola’ Grapes in a Semi-Arid Environment
2021
The present work studied the effect of two consecutive years of regulated deficit irrigation (RDI) compared to rain fed management on the vegetative growth, yield, and quality of ‘Nero d’Avola’ grapes. The trial was conducted separately in two soils (vertisol and entisol) located at the top and bottom hillside of the same vineyard. Vertisol was characterized by greater depth, organic matter, exchangeable K20, and total N than entisol. RDI was based on an irrigation volume at 25% of estimated crop evapotranspiration (ETc) up to end of veraison and 10% of estimated ETc up to 15 days before harvest. Predawn water potential (PDWP) was used as indicator of plant water status and irrigation timin…
Predicting soil and plant water status dynamic in olive orchards under different irrigation systems with Hydrus-2D: Model performance and scenario an…
2018
The paper analyzes the performance of Hydrus-2D model to simulate the dynamic of soil water contents and transpiration fluxes in an olive orchard in which two different irrigation systems were used in 2011 and 2012. The relationship between measured midday stem water potential, MSWP, and simulated relative transpiration (ratio between simulated actual and maximum crop transpiration), Ks, was also identified with the aim to use the model for crop water status predictions. Finally, a scenario analysis was carried out for irrigation management purposes, by considering the level of crop water stress achieved in the different phases of the vegetative growth. The results evidenced that active roo…
The Effect of Plant Water Status on the Chemical Composition of Pistachio Nuts (Pistacia vera L. Cultivar Bianca)
2020
Pistachio nuts are worldwide appreciated for their chemical and organoleptic profiles. There are several studies on the influence of irrigation on pistachio productivity, whereas there are little available data on the influence on nut quality. In this study we characterized some qualitative traits of pistachio nuts cultivar Bianca in Mediterranean environment and how plant water status affected them. Water status had a positive and significant influence on the chlorophylls content, nuts from less stressed trees showed higher values of chlorophyll a (14.7 mg/100 g) and b (21.1 mg/100 g) compared than more stressed trees (9.3 and 11.5 mg/100 g for a and b, respectively). Solid phase microextr…
Using field measurements and FAO-56 model to assess the eco-physiological response of citrus orchards under regulated deficit irrigation
2017
[EN] Micro-irrigation is considered one of the most efficient water distribution systems and allows increasing water use efficiency if coupled with effective water-saving irrigation management strategies as regulated deficit irrigation (RDI) or partial root-zone drying (PRD) techniques. However, application of these strategies makes it crucial the real-time monitoring of soil and crop water status, in order to identify appropriate irrigation scheduling parameters (irrigation timing and doses) and to prevent irreversible damage of plant system and/or crop yield reductions. Even if midday stem water potential (MSWP) is considered one of the most affordable indicator for direct determinations …
Recurrent deficit irrigation and fruit harvest affect tree water relations and fruitlet growth in ‘valencia’ orange
2019
Background – Partial rootzone drying is an irrigation strategy known for increasing water use efficiency without significantly affecting tree water status. ‘Valencia’ oranges have a very long development period and nearly mature fruit and new fruitlets may be present at the same time on the tree, competing for water and assimilates. Objectives – The present study investigates the effect of recurrent deficit irrigation and fruit harvest on tree water status and fruitlet growth of ‘Valencia’ orange. Methods – Forty-eight adult trees were exposed to three irrigation treatments for seven years (2007–2013): irrigation with 100% of ETc (CI), continuous deficit irrigation (DI, 50% of CI) and parti…