scholarly journals Hydraulic Traits Performances of Three Pine Species in Tunisia

2019 ◽  
Vol 11 (13) ◽  
pp. 20
Author(s):  
Sameh Cherif ◽  
Olfa Ezzine ◽  
Mohamed Larbi Khouja ◽  
Zouhaier Nasr
Keyword(s):  
Hydraulic Conductivity ◽  
Water Potential ◽  
Mediterranean Forests ◽  
Stem Water Potential ◽  
Humid Climate ◽  
Safety Margins ◽  
Hydraulic Safety ◽  
The Impact ◽  
Semi Arid ◽  
Pine Species

Mediterranean forests including Tunisian pine species are threatened by the rising of temperature and decreasing of precipitation. The impact of the increase of aridity differs across species depending on their stomatal and hydraulic responses. In this paper, three pine species: P. halepensis, P. brutia and P. canariensis growing in three different climatic zones: humid, sub-humid and semi-arid, were studied to detect their different responses to drought and guide their selection for reforestation program. Measurements carried out are hydraulic conductivity at point P50, specific conductivity (Ks), midday stem water potential and hydraulic safety margins. Results showed that during summer, vulnerability to embolism, estimated by water potential inducing 50% loss of xylem hydraulic conductivity (P50), is strongly associated with the capacity for drought resistance. Pinus halepensis (P50 = -4.19 MPa) was found to be more resistant to drought than P. brutia and P. canariensis in the semi-arid climate, whereas P. brutia tolerated the humid climate (P50 = -3.7 MPa) and P. canariensis seems more adapted to the sub-humid climate (P50 = -4.08 MPa). Hydraulic safety margins confirmed the conservative behavior of pine species to avoid drought and for maintaining relatively high water potential in dry conditions. These findings help to assess the impact of mid-summer water deficit on pine species in the context of climate change and to select among these species the most resistant for future reforestation programs.

The decline in xylem flow to mango fruit at the end of its development is related to the appearance of embolism in the fruit pedicel

2015 ◽  
Vol 42 (7) ◽  
pp. 668 ◽  
Author(s):  
Thibault Nordey ◽  
Mathieu Léchaudel ◽  
Michel Génard
Keyword(s):  
Hydraulic Conductivity ◽  
Water Potential ◽  
Fruit Development ◽  
Hydraulic Properties ◽  
Potential Gradient ◽  
Mango Fruit ◽  
Xylem Flow ◽  
Water Potential Gradient ◽  
The Impact ◽  
Late Growth

The decline in xylem flow during the late growth stage in most fruits may be due either to a decrease in the water potential gradient between the stem bearing the fruit and the fruit tissues or to a decrease in the hydraulic conductivity of xylem vessels, or both. In this study, we analysed changes in xylem flows to the mango Mangifera indica L. fruit during its development to identify the sources of variation by measuring changes in the water potential gradient and in the hydraulic properties of the fruit pedicel. The variations in xylem and transpiration flows were estimated at several stages of mango fruit development from the daily changes in the fresh mass of detached and girdled fruits on branches. The water potential gradient was estimated by monitoring the diurnal water potential in the stem and fruit. The hydraulic properties of the fruit pedicel were estimated using a flow meter. The results indicated that xylem flow increased in the early stages of fruit development and decreased in the late stage. Variations in xylem flow were related to the decrease in the hydraulic conductivity of xylem vessels but not to a decrease in the water potential gradient. The hydraulic conductivity of the fruit pedicel decreased during late growth due to embolism caused by a decrease in the fruit water potential. Further studies should establish the impact of the decrease in the hydraulic conductivity of the fruit pedicel on mango growth.

The hydraulic architecture of Eucalyptus trees growing across a gradient of depth-to-groundwater

2015 ◽  
Vol 42 (9) ◽  
pp. 888 ◽  
Author(s):  
Sepideh Zolfaghar ◽  
Randol Villalobos-Vega ◽  
Melanie Zeppel ◽  
Derek Eamus
Keyword(s):  
Hydraulic Conductivity ◽  
Leaf Area ◽  
Water Availability ◽  
Safety Margin ◽  
Hydraulic Architecture ◽  
Sapwood Area ◽  
Huber Value ◽  
Xylem Vulnerability ◽  
Safety Margins ◽  
Hydraulic Safety

Heterogeneity in water availability acts as an important driver of variation in plant structure and function. Changes in hydraulic architecture represent a key mechanism by which adaptation to changes in water availability can be expressed in plants. The aim of this study was to investigate whether differences in depth-to-groundwater influence the hydraulic architecture of Eucalyptus trees in remnant woodlands within mesic environments. Hydraulic architecture of trees was examined in winter and summer by measuring the following traits: Huber value (HV: the ratio between sapwood area and leaf area), branch hydraulic conductivity (leaf and sapwood area specific), sapwood density, xylem vulnerability (P50 and Pe) and hydraulic safety margins across four sites where depth-to-groundwater ranged from 2.4 to 37.5 m. Huber value increased significantly as depth-to-groundwater increased. Neither sapwood density nor branch hydraulic conductivity (sapwood and leaf area specific) varied significantly across sites. Xylem vulnerability to embolism (represented by P50 and Pe) in both seasons was significantly and negatively correlated with depth-to-groundwater. Hydraulic safety margins increased with increasing depth-to-groundwater and therefore trees growing at sites with deeper water tables were less sensitive to drought induced embolism. These results showed plasticity in some, but not all, hydraulic traits (as reflected in HV, P50, Pe and hydraulic safety margin) in response to increase in depth-to-groundwater in a mesic environment.

scholarly journals Impact of Root Growth on the Physical Properties of Peat Substrate under a Constant Water Regimen

HortScience ◽  
2011 ◽  
Vol 46 (10) ◽  
pp. 1394-1399 ◽  
Author(s):  
Patrice Cannavo ◽  
Houda Hafdhi ◽  
Jean-Charles Michel
Keyword(s):  
Hydraulic Conductivity ◽  
Root Growth ◽  
Water Potential ◽  
Water Retention ◽  
Total Porosity ◽  
Unsaturated Hydraulic Conductivity ◽  
Shoot Weight ◽  
The Impact ◽  
New Guinea Impatiens ◽  
Water Holding

The impact of root growth on the hydraulic properties of peat substrate was investigated under optimal water retention, i.e., at a constant water potential of –1 kPa. ‘New Guinea’ impatiens was grown in 1.1-L cylindrical containers for 196 d in a greenhouse under controlled climate and fertilization conditions. Water retention and hydraulic conductivity curves, root biomass and volume, and shoot weight were measured. Results indicated a maximal root volumetric content of 0.065 m3·m−3 that was as high as the peat content in containers (0.068 m3·m−3). From Day 0 to Day 196, the total porosity of the growing media decreased from 0.931 m3·m−3 to 0.874 m3·m−3. Moreover, considering the water-holding capacity at a water potential of –1 kPa, it increased from 0.58 to 0.75 m3·m−3 (i.e., by 29.3%) without changes in water availability but with a large decrease in air-filled porosity from 0.35 to 0.14 m3·m−3. The unsaturated hydraulic conductivity K(θ) decreased as a result of root growth. Root growth also modified pore size distribution and pore structure. Hydraulic conductivity curves indicated a better pore connectivity reflected by a decrease in tortuosity.

Response of ungrafted and grafted grapevine cultivans and rootstocks (Vitis sp.) to water stress

OENO One ◽  
2007 ◽  
Vol 41 (2) ◽  
pp. 85 ◽  
Author(s):  
Imene Toumi ◽  
Wissal M'Sehli ◽  
Soumaya Bourgou ◽  
Neila Jallouli ◽  
Asma Bensalem-Fnayou ◽  
...  
Keyword(s):  
Water Stress ◽  
Water Potential ◽  
Dry Matter ◽  
Soluble Sugars ◽  
Water Shortage ◽  
Stem Water Potential ◽  
Matter Production ◽  
Stem Water ◽  
The Impact ◽  
Progressive Water Stress

<p style="text-align: justify;"><strong>Aims</strong>: The responses of two Vitis vinifera cultivars (Cardinal and Superior Seedless) and two rootstocks (110R and SO4) to drought, the effect of grafting and the interactions of scion/rootstock were investigated.</p><p style="text-align: justify;"><strong>Methods and results</strong>: The vines were subjected to a progressive water stress in greenhouse controlled conditions. At the end of the water stress treatments, physiological analyses were carried out (stem water potential, dry matter production, soluble sugars, proline as well as ions Na+ and K+). Drought was expressed by the drop of the stem water potential in the stressed vines as compared to their controls. Furthermore, tolerance and sensitivity were linked to the accumulation of soluble sugars and proline as well as the equilibrium of K+ and Na+ in the leaves.</p><p style="text-align: justify;"><strong>Conclusion</strong>: When ungrafted, Cardinal was more tolerant to water stress than Superior Seedless. The grafted vines exhibited more vigour, moreover, the combination of Cardinal with SO4 and Superior Seedless with 110R revealed to be the advantageous associations under water stress.</p><p style="text-align: justify;"><strong>Significance and impact of study</strong>: This work has been carried out to investigate the differential responses of grapevine cultivars to drought stress and the impact of grafting under water shortage conditions.</p>

scholarly journals Regulated deficit irrigation and tommy atkins mango orchard productivity under microsprinkling in brazilian semi arid

2011 ◽  
Vol 31 (6) ◽  
pp. 1052-1063 ◽  
Author(s):  
Carlos E Cotrim ◽  
Maurício A Coelho Filho ◽  
Eugênio F Coelho ◽  
Márcio M Ramos ◽  
Paulo R Cecon
Keyword(s):  
Water Potential ◽  
Deficit Irrigation ◽  
Soil Water Potential ◽  
Field Capacity ◽  
Stem Water Potential ◽  
Regulated Deficit Irrigation ◽  
Mango Tree ◽  
Arid Conditions ◽  
Stem Water ◽  
Semi Arid

This study aimed to test controlled levels of water deficiency in soil in mango trees, under microsprinkling irrigation, in semi-arid conditions, and to evaluate its effect in the productivity and fruits quality. The deficits were applied in the phases I, II and III of growth of the fruit, during the productive cycles of the mango tree in 2006 and 2007. The experiment in both cases was arranged in an entirely random design with 10 treatments and 3 repetitions, in the year I, and with 8 treatments and 3 repetitions in the year II. The values of soil water potential, of the treatments submitted to regulated deficit irrigation (RDI), were placed in the range of 0 to -0.011 MPa, showing that the soil humidity varied between the saturation and the field capacity, not characterizing deficit water condition. The average values of stem water potential (Ψstem) varied between -0.90 and -1.74 MPa, evidencing significant effect (p <0.05) just for T1 (without irrigation), T7 and T8 (RDI with 30% of the ETc in the phases II and III, respectively). Through the variance analysis, significant differences were not verified among productivity, number of fruits per plant and size of the fruit, in none of the experiments, what indicates the possibility of reduction of the water use in the irrigation of the mango tree without significant losses of productivity and fruit quality.

A dynamic simulation approach to soil salinity and sodicity control

2021 ◽  
Author(s):  
Mehmet Can Tunca ◽  
Ali Kerem Saysel ◽  
Masoud Babaei ◽  
Günay Erpul
Keyword(s):  
Hydraulic Conductivity ◽  
System Dynamics ◽  
Soil Fertility ◽  
Solute Transport ◽  
Dynamic Simulation ◽  
Soil Salinity ◽  
And Control ◽  
The Impact ◽  
Semi Arid ◽  
Irrigation Practices

&lt;p&gt;Soil salinity and sodicity are twin problems potentially affecting soil fertility, farmers&amp;#8217; livelihoods and food security. Management and control of these problems, particularly on irrigated farmlands require knowledge and expertise crafted through appropriate models and experiments. The accumulation of salts on the soil profiles may occur through natural processes (of weathering of soil minerals, saline groundwater intrusion), as well as by human actions, that are mostly related to poor agricultural and irrigation practices. While accumulation of salt in soil water impedes crop evapotranspiration, sodicity (abundance of sodium cations among others) threatens the soil structure and degrades its hydraulic qualities. These problems are more pervasive in arid and semi-arid regions, where inadequate precipitation rates compared to evapotranspiration limit leaching of salts and facilitates their accumulation in productive topsoil. Therefore, irrigation and agricultural practices are crucial in controlling these problems to avoid their undesired consequences.&lt;br&gt;We build a dynamic simulation model of salinization and sodification in soil layers so as to test the impact of alternative irrigation practices with respect to water quality, quantity and schedule, on soil fertility and farm yields. The model is developed based on the system dynamics methodology, providing a feedback rich understanding of hydraulic, solute, and crop processes. While the hydraulic flow is the driver of solute transport, salinity and sodicity influences the hydraulic flows through their impact on evapotranspiration and hydraulic conductivity. The crop growth and its demand for evapotranspiration at various stages of development is modeled, considering available moisture and the accumulation of salts in the rootzone. Moreover, the model investigates farmers&amp;#8217; response to salinity and sodicity through adoption of different irrigation practices and crop choices, so as to observe the long-term development of the problem under the conditions of adaptive management.&lt;br&gt;The model has a generic theoretical structure that benefits from soil physics to formulate the complex processes of hydraulic flows and solute transport. Model parameter values are selected as representative of the field conditions of Konya Plain in Turkey, which is a semi-arid region partially experiencing soil salinization problems. As a part of the research project entitled, &amp;#8220;Soil Salinity and Sodicity Management by Sustainable Irrigation Practices in Konya Plain&amp;#8221;, the Interdisciplinary Multi-Institutional Network, during model validation phase, we will utilize data from the soil experiments that are conducted by our research partners. These data will include, however will not be limited to the experimentally characterized porosity and hydraulic conductivity curves. Ultimately, the model will provide an experimental platform to manage and control soil salinity and sodicity under different environmental conditions and farmer responses.&lt;br&gt;&lt;br&gt;&lt;strong&gt;Keywords&lt;/strong&gt;: Soil Salinity, Soil Sodicity, System Dynamics, Irrigation, Agriculture&lt;br&gt;&lt;br&gt;&lt;strong&gt;Acknowledgement&lt;/strong&gt;: This work was supported by the Scientific and Technological Research Council of Turkey [Project Number: TUBITAK-118Y343]&lt;br&gt;&amp;#160;&lt;/p&gt;

scholarly journals Midday Stem Water Potential Values Needed to Maintain Photosynthesis and Leaf Gas Exchange Established for Pecan

2014 ◽  
Vol 139 (5) ◽  
pp. 537-546 ◽  
Author(s):  
Yahia Othman ◽  
Dawn VanLeeuwen ◽  
Richard Heerema ◽  
Rolston St. Hilaire
Keyword(s):  
Gas Exchange ◽  
Water Potential ◽  
Leaf Gas Exchange ◽  
Water Status ◽  
Irrigation Scheduling ◽  
Stem Water Potential ◽  
Flood Irrigation ◽  
Dry Down ◽  
Stem Water ◽  
The Impact

Demand for New Mexico’s limited water resources coupled with periodic drought has increased the necessity for tree water status monitoring to guide irrigation scheduling of pecan (Carya illinoinensis) orchards. The objectives of this study were to assess the impact of water status developed during the flood irrigation dry-down cycles on photosynthesis (Pn), and gas exchange [stomatal conductance (gS) to H2O (gH2O), transpiration (E), and intercellular CO2 (ci)] and to establish values of midday stem water potential (Ψsmd) that are needed to maintain Pn and gas exchange of pecan. We conducted the study simultaneously on two southern New Mexico mature pecan orchards from 2011 through 2013. Flood irrigation as determined by grower practice was used on both orchards and Pn, gH2O, E, and ci were assessed at Ψsmd of –0.4 to –2.0 MPa. Photosynthesis and gas exchange were higher in pecan trees shortly after irrigation than trees exhibiting water deficit near the end of a flood irrigation dry-down cycle. The decline in Pn was markedly noticeable when Ψsmd dropped below –0.9 MPa. We attributed the reduction in Pn mostly to stomatal limitation. The decline in Pn and gH2O exceeded 50% when Ψsmd ranged from –1.5 to –2.0 MPa. For those reasons, we recommended that pecan orchards be maintained at Ψsmd higher than –0.90 MPa to prevent significant reductions in carbon assimilation and gas exchange.

scholarly journals The Effect of Irrigation Rate on the Water Relations of Young Citrus Trees in High-Density Planting

2021 ◽  
Vol 13 (4) ◽  
pp. 1759
Author(s):  
Said A. Hamido ◽  
Kelly T. Morgan
Keyword(s):  
Water Potential ◽  
Soil Water ◽  
Soil Salinity ◽  
Planting Density ◽  
Stem Water Potential ◽  
Irrigation Rate ◽  
Biological Stress ◽  
Stem Water ◽  
Water Contents ◽  
Soil Water Contents

The availability and proper irrigation scheduling of water are some of the most significant limitations on citrus production in Florida. The proper volume of citrus water demand is vital in evaluating sustainable irrigation approaches. The current study aims to determine the amount of irrigation required to grow citrus trees at higher planting densities without detrimental impacts on trees’ water relation parameters. The study was conducted between November 2017 and September 2020 on young sweet orange (Citrus sinensis) trees budded on the ‘US-897’ (Cleopatra mandarin x Flying Dragon trifoliate orange) citrus rootstock transplanted in sandy soil at the Southwest Florida Research and Education Center (SWFREC) demonstration grove, near Immokalee, Florida. The experiment contained six planting densities, including 447, 598, and 745 trees per ha replicated four times, and 512, 717, and 897 trees per ha replicated six times. Each density treatment was irrigated at 62% or 100% during the first 15 months between 2017 and 2019 or one of the four irrigation rates (26.5, 40.5, 53, or 81%) based on the calculated crop water supplied (ETc) during the last 17 months of 2019–2020. Tree water relations, including soil moisture, stem water potential, and water supplied, were collected periodically. In addition, soil salinity was determined. During the first year (2018), a higher irrigation rate (100% ETc) represented higher soil water contents; however, the soil water content for the lower irrigation rate (62% ETc) did not represent biological stress. One emitter per tree regardless of planting density supported stem water potential (Ψstem) values between −0.80 and −0.79 MPa for lower and full irrigation rates, respectively. However, when treatments were adjusted from April 2019 through September 2020, the results substantially changed. The higher irrigation rate (81% ETc) represented higher soil water contents during the remainder of the study, the lower irrigation rate (26.5% ETc) represents biological stress as a result of stem water potential (Ψstem) values between −1.05 and −0.91 MPa for lower and higher irrigation rates, respectively. Besides this, increasing the irrigation rate from 26.5% to 81%ETc decreased the soil salinity by 33%. Although increasing the planting density from 717 to 897 trees per hectare reduced the water supplied on average by 37% when one irrigation emitter was used to irrigate two trees instead of one, applying an 81% ETc irrigation rate in citrus is more efficient and could be managed in commercial groves.

scholarly journals Effect of Organic Amendment Addition on Soil Properties, Greenhouse Gas Emissions and Grape Yield in Semi-Arid Vineyard Agroecosystems

Agronomy ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1477
Author(s):  
Antonio Marín-Martínez ◽  
Alberto Sanz-Cobeña ◽  
Mª Angeles Bustamante ◽  
Enrique Agulló ◽  
Concepción Paredes
Keyword(s):  
Soil Fertility ◽  
Soil Properties ◽  
Greenhouse Gas ◽  
Co2 Emissions ◽  
Organic Amendments ◽  
Organic N ◽  
N2o Emissions ◽  
The Impact ◽  
Semi Arid ◽  
Grape Yield

In semi-arid vineyard agroecosystems, highly vulnerable in the context of climate change, the soil organic matter (OM) content is crucial to the improvement of soil fertility and grape productivity. The impact of OM, from compost and animal manure, on soil properties (e.g., pH, oxidisable organic C, organic N, NH4+-N and NO3−-N), grape yield and direct greenhouse gas (GHG) emission in vineyards was assessed. For this purpose, two wine grape varieties were chosen and managed differently: with a rain-fed non-trellising vineyard of Monastrell, a drip-irrigated trellising vineyard of Monastrell and a drip-irrigated trellising vineyard of Cabernet Sauvignon. The studied fertiliser treatments were without organic amendments (C), sheep/goat manure (SGM) and distillery organic waste compost (DC). The SGM and DC treatments were applied at a rate of 4600 kg ha−1 (fresh weight, FW) and 5000 kg ha−1 FW, respectively. The use of organic amendments improved soil fertility and grape yield, especially in the drip-irrigated trellising vineyards. Increased CO2 emissions were coincident with higher grape yields and manure application (maximum CO2 emissions = 1518 mg C-CO2 m−2 d−1). In contrast, N2O emissions, mainly produced through nitrification, were decreased in the plots showing higher grape production (minimum N2O emissions = −0.090 mg N2O-N m−2 d−1). In all plots, the CH4 fluxes were negative during most of the experiment (−1.073−0.403 mg CH4-C m−2 d−1), indicating that these ecosystems can represent a significant sink for atmospheric CH4. According to our results, the optimal vineyard management, considering soil properties, yield and GHG mitigation together, was the use of compost in a drip-irrigated trellising vineyard with the grape variety Monastrell.

scholarly journals Evaluation of a Coupled Model to Predict the Impact of Adaptive Behaviour in the Thermal Sensation of Occupants of Naturally Ventilated Buildings in Warm-Humid Regions

2020 ◽  
Vol 13 (1) ◽  
pp. 255
Author(s):  
Luciano C. de Faria ◽  
Marcelo A. Romero ◽  
Lúcia F. S. Pirró
Keyword(s):  
Computational Models ◽  
Thermal Sensation ◽  
Coupled Model ◽  
Adaptive Behaviour ◽  
Humid Climate ◽  
Clothing Insulation ◽  
Tropical Regions ◽  
Naturally Ventilated Buildings ◽  
Adaptive Behaviours ◽  
The Impact

Improving indoor environment quality and making urban centres in tropical regions more sustainable has become a challenge for which computational models for the prediction of thermal sensation for naturally ventilated buildings (NVBs) have major role to play. This work performed analysis on thermal sensation for non-residential NVBs located in Brazilian tropical warm-humid climate and tested the effectiveness of suggested adaptive behaviours to mitigate warm thermal sensation. The research method utilized transient computational fluid dynamics models coupled with a dynamic model for human thermophysiology to predict thermal sensation. The calculated results were validated with comparison with benchmark values from questionnaires and from field measurements. The calculated results for dynamic thermal sensation (DTS) seven-point scale showed higher agreement with the thermal sensation vote than with the predicted mean vote. The test for the suggested adaptive behaviours considered reducing clothing insulation values from 0.18 to 0.32 clo (reducing DTS from 0.1 to 0.9), increasing the air speed in 0.9 m/s (reducing DTS from 0.1 to 0.9), and applying both suggestions together (reducing DTS from 0.1 to 1.3) for five scenarios with operative temperatures spanning 34.5–24.0 °C. Results quantified the tested adaptive behaviours’ efficiency showing applicability to improve thermal sensation from slightly-warm to neutral.

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