The response of Evapotranspiration to osmotic potential in small-scale lab lysimeters

2021 ◽  
Author(s):  
Adil Salman ◽  
Wolfgang Durner ◽  
Deep C. Joshi ◽  
Mahyar Naseri
Keyword(s):  
Water Potential ◽  
Soil Water ◽  
Osmotic Potential ◽  
Soil Water Potential ◽  
Matric Potential ◽  
Soil Material ◽  
Total Soil ◽  
Evapotranspiration Rate ◽  
Soil Osmotic Potential ◽  
Total Soil Water Potential

<p>Drought and climatic change are among the main environmental stressors for the water and soil qualities. Soil water potential is the major soil-related factor controlling water availability to plants and their evapotranspiration. It consists of two main components: matric and osmotic potential. Although the effect of matric potential on plant evapotranspiration has been extensively studied under various conditions, there is still a lack of quantitative studies on the effects of osmotic potential on evapotranspiration.</p><p>In our study, we investigated the influence of soil osmotic potential on the evapotranspiration rate and cumulative evapotranspiration of grass planted in small laboratory lysimeters. A sandy loam soil material was packed in four lysimeters with a volume of 6000 cm<sup>3</sup> and equal bulk density. The soil material was air dried, freed from roots and passed through a 2 mm sieve. Each lysimeter was equipped with soil sensors at two different depths to monitor soil moisture, bulk electrical conductivity, temperature, and matric potential. To obtain continuous mass balance measurements, each lysimeter was placed on a balance connected to the computer. Grass seeds were planted in each lysimeter at the same density and irrigated with distilled water until plant height was 12 cm. Irrigation water of two different qualities (EC= 0 and 4.79 dS/m) was then applied to produce different levels (0 and -0.17 MPa) of osmotic potential. The volumetric water content was adjusted to a value between 15 and 20 % in each lysimeter during the grass growth period. When the volumetric water content reached 15 %, irrigation water was added to the lysimeters to increase it to 20 %. Data were collected to calculate changes in osmotic potential relative to changes in total soil water potential. In addition, the relationship between osmotic potential and evapotranspiration rate during the growing season was determined.</p><p>Our results indicate a controlling role of soil osmotic potential on total soil water potential. This role results a significant reductions in evapotranspiration in response to increases in osmotic potential, in addition to effects on plant health. Osmotic potential has a significant function on total soil water potential when the soil becomes dry and poor water qualities are used in irrigation.</p>

Soil water matric potential rather than water content determines drought responses in field-grown lupin (Lupinus angustifolius)

1998 ◽  
Vol 25 (3) ◽  
pp. 353 ◽  
Author(s):  
C.R. Jensen ◽  
V.O. Mogensen ◽  
H.-H. Poulsen ◽  
I.E. Henson ◽  
S. Aagot ◽  
...  
Keyword(s):  
Water Potential ◽  
Water Content ◽  
Soil Water ◽  
Stomatal Closure ◽  
Soil Water Potential ◽  
Root Surface ◽  
Lupinus Angustifolius ◽  
Soil Drying ◽  
Matric Potential ◽  
Aba Content

Drought responses in leaves of lupin (Lupinus angustifolius L., cv. Polonez) were investigated in plants grown in lysimeters either in a sand or in a loam soil in the field. Abscisic acid (ABA) content, water potential (ψl) and conductance to water vapour (gH2O) were determined in leaves of both irrigated plants and in plants exposed to gradual soil drying. Amorning-peak of leaf ABA content was found in both fully watered and droughted plants. During soil drying which, on both soils types, only decreased soil water potential of the upper soil layers, mid-day leaf ABA content increased relative to that in fully irrigated plants before any appreciable decreases occurred in ψl. In the part of the soil profile from which water was taken up (0–60 cm depth), gH2O decreased when the relative available soil water content (RASW) on sand was below 12% and RASW on loam, below 30%. At this point the average soil water matric potential (ψsoil) on sand was less than –0.13 MPa and the fraction of roots in ‘wet’ soil was 0.12, while on loam, the fraction of roots in ‘wet’ soil was 0.44 while y soil was similar to that on sand. A critical leaf ABA content of 300–400 ng/g FW was associated with the onset of stomatal closure on both soil types. We suggest that the initial stomatal closure is controlled by ABA which originates from the roots where its production is closely related to ψsoiland the water potential of the root surface and that ψsoil is a more important parameter than RASW or the fraction of roots in ‘wet’ soil for affecting leaf gas exchange. Further drying on both soils led to further increases in leaf ABA and declines in ψl and gH2O. In order to gain further insight, experiments should be designed which combine signalling studies with simulation studies, which take account of soil water potential, root contact area and water flux when calculating the water status at the root surface in the soil-plant-atmosphere-continuum.

scholarly journals Relationship between Soil and Plant Water Status in Wine Grapes under Various Water Deficit Regimes

2010 ◽  
Vol 20 (3) ◽  
pp. 585-593 ◽  
Author(s):  
Ana Centeno ◽  
Pilar Baeza ◽  
José Ramón Lissarrague
Keyword(s):  
Water Potential ◽  
Soil Water ◽  
Leaf Water Potential ◽  
Water Status ◽  
Soil Water Potential ◽  
Threshold Value ◽  
Leaf Water ◽  
Wine Grape ◽  
Soil Matric Potential ◽  
Matric Potential

Limited water supply in arid and semiarid Mediterranean environments demands improving irrigation efficiency. The purpose of this study was to determine a functional relationship between soil water availability and wine grape (Vitis vinifera) water status to determine a threshold value of soil matric potential to trigger irrigation. Seasonal trends of soil water potential, leaf water potential, and stomatal conductance (gS) of ‘Tempranillo’ wine grape were determined in two deficit irrigation treatments replenishing 45% and 30% of the reference evapotranspiration, and in a third non-irrigated treatment during 2001 and 2002. Soil water potential was measured with granular matrix soil moisture sensors placed at 0.3 m (Ψ0.3), 0.6 m (Ψ0.6), and 1.2 m (Ψ1.2) depths. The sensors at 0.3 m depth quickly responded to irrigation by increasing Ψ0.3 levels. At the 0.6 m depth, Ψ0.6 progressively decreased, showing significant differences between T1 and the rest of the treatments, while no significant differences in Ψ1.2 were found. All relationships between profile soil matric potential and leaf water potential and gS were highly correlated. After integrating our data with previous studies, we suggest a whole profile soil water potential value of –0.12 MPa as threshold to trigger irrigation and avoid severe water stress during berry growth.

Response of the components of sugar beet leaf water potential to a drying soil profile

1987 ◽  
Vol 109 (3) ◽  
pp. 437-444 ◽  
Author(s):  
Kay F. Brown ◽  
M. McGowan ◽  
M. J. Armstrong
Keyword(s):  
Sugar Beet ◽  
Water Potential ◽  
Soil Water ◽  
Leaf Water Potential ◽  
Osmotic Potential ◽  
Seasonal Changes ◽  
Water Movement ◽  
Soil Water Potential ◽  
Leaf Water ◽  
Leaf Osmotic Potential

SummaryFor many field-grown crops, including sugar beet, there is little information on the seasonal changes in leaf water potential and its components as the soil dries. Therefore, seasonal changes in leaf water, osmotic and turgor potentials of sugar beet were measured in two seasons, in crops that experienced differing degrees of soil moisture stress. In 1983 potentials of crops exposed to early and late droughts were compared with those of irrigated crops, and in 1984 measurements were made in a non-irrigated crop. In the irrigated crop the midday leaf water potential changed little during the season, except in response to fluctuating evaporative demand. In the drought and non-irrigated treatments there was a sharp fall in leaf water potential as soon as the soil water potential decreased. The size of the midday leaf water potential was primarily determined by soil dryness. However, the leaf water potential did not decrease below about — 1·5 MPa in either year. The leaf osmotic potential declined at the same time as the leaf water potential, but the extent to which this happened differed in the two years. Only in the 1984 non-irrigated crop did the osmotic potential continue to decrease as the soil dried, suggesting that osmotic adjustment had taken place in 1984 but not in 1983. Thus higher turgor was maintained in the 1984 crop than in the 1983 drought-affected crops. Some turgors were recorded as apparently negative in 1983.Since the leaf water potential declined to a minimum of about — 1·5 MPa, the soil water potential minima were also about — 1·5 MPa. However, deeper soil was not dried to this extent, suggesting that the extra resistance for water uptake from deep soil was limiting or the rooting density was too low.The pattern of recovery of leaf water potential overnight suggested that the rhizosphere resistance to water movement was small, even as the soil dried. However, measurement of stem water potentials in 1984 indicated that a significant resistance to water flow existed within the aerial part of sugar beet plants. This shows that the use of the water potential in leaves as an estimate of that in stems or roots can be misleading.

scholarly journals Water Relations of Two Adjacently Growing Tree Species Shorea Robusta Gaertn-and Pinus Roxburbhii Sarg-in the Lower Himalayan Region

2020 ◽  
Vol 15 (3) ◽  
pp. 446-453
Author(s):  
Ashish Tewari
Keyword(s):  
Water Potential ◽  
Soil Water ◽  
Tree Species ◽  
Osmotic Potential ◽  
Soil Water Potential ◽  
Winter Season ◽  
Early Summer ◽  
Summer Season ◽  
Pinus Roxburghii ◽  
Shorea Robusta

Water potential (predawn and mid day), water potential components (osmotic potential at full and zero turgor, relative water content), soil water potential and leaf conductance were measured for two adjacently growing tree species Shorea robusta Gaertn and Pinus roxburghii Sarg. at an elevation of 1370m. The stands were open and the density of S. robusta was 212 trees/ha and of P. roxburghii was 141trees/ha. Presence of high number of saplings indicates both the species were regenerating well in the site despite human disturbance. S. robusta maintained relatively high predawn water potential even in summers (above -0.50MPa) and P. roxburghii showed low predawn water potential in early summer and summer season (above-1.4 MPa). P. roxburghii maintained a relatively small daily change in water potential during early summer and summer season (0.33MPa and 0.27MPa) indicating greater ability of the species to close its stomata as drought intensifies. The values of osmotic potential at full and zero turgor remained more or less constant for S. robusta from monsoon to winter and then declined during early summer. P. roxburghii showed a gradual decline in osmotic potential values from monsoon to winter season. Chir-pine has the ability of invade and grow on sites that are water stressed which can be related to its capacity to show high osmotic adjustment.. The most negative values of soil water potential were in early summer in both years. The morning and afternoon conductance was lowest during early summer and highest in autumn season.

scholarly journals The influence of soil water potential and soil temperature on the seedling emergence of wheat and barley

1986 ◽  
Vol 58 (4) ◽  
pp. 185-190 ◽  
Author(s):  
Markku Tenhovuori
Keyword(s):  
Water Potential ◽  
Soil Water ◽  
Water Uptake ◽  
Seedling Emergence ◽  
Soil Water Potential ◽  
Matric Potential ◽  
Initial Water ◽  
Emergence Period ◽  
Increasing Temperature ◽  
Clear Increase

The time for 50 % emergence of wheat and barley increases linearly with decreasing matric potential. This increase actually begins at matric pressures above pF 2.7. The rise in temperature makes emergence faster with in the range of minimum temperature (3.1°C for wheat and 1.9°C for barley) and the temperature where growth begins to slow down(about 31°C for wheat and 27°C for barley).The optimum range for 50 % emergence was obtained at a matric pressure range of pF 1.3—2.7 or —5.0— —0.20 m (water column) at a temperature of 10°C, which quite well corresponds to the situation in Finland during the emergence period in spring. A clear increase can be observed in the required heat sum for wheat and barley when the soil water potential reaches a critical point which was pF 2.8 or—6.3m for wheat and pF 2.7 or —5.0 m for barley. The total emergence as a function of matric potential for wheat and barley was determined over a period of 30 days at 10°C. In the wet side, pF 1,0 can be considered a limit, the total emergence decreasing with lower values. In the dry side, a corresponding decrease can be noticed in total emergence at pF above 3.0. The water uptake by seeds speeded up with increasing temperature from 10 to 25°C. Radicles of wheat and barley began to appear when the water uptake by the seed was approximately 50—60 % of the initial weight of the seed. The initial water uptake caused by the moistening of the pericarp due to capillarity was about 3 % for wheat and 5 % for barley at a soil water potential of pF 1.2.

Response in Plant Water Status to Integrated Values of Soil Matric Potential Calculated From Soil Water Depletion by a Field Bean Crop

1980 ◽  
Vol 7 (1) ◽  
pp. 51 ◽  
Author(s):  
AJ Karamanos
Keyword(s):  
Water Potential ◽  
Soil Water ◽  
Soil Depth ◽  
Soil Water Potential ◽  
Field Bean ◽  
Soil Matric Potential ◽  
Matric Potential ◽  
Water Depletion ◽  
Soil Layers ◽  
Bean Crop

Water deficits were induced in a field bean crop using Polythene rainout shelters to study the crop response to changes in soil matric potential integrated over the zone of soil water extraction. Integrated values of soil matric potential (Ψm,s) were derived from the values of matric potential (Ψm,s) at four separate depths weighted according to the corresponding rates of water depletion at the time of measurement. Linear relationships existed between Ψm,s and variations in leaf water potential before sunrise (Ψd) and in the afternoon (Ψa). The total resistance to daily water flow in the soil-plant system was found to increase linearly with falling Ψm,s. The water flux from separate soil layers indicated that the deeper the layer, the greater the resistance to water uptake from soils at a given value of soil water potential. Such an increase in resistance with soil depth, which considerably reduced the availability of soil water in the deeper soil layers, was attributed mainly to plant factors.

Effect of Soil Water Potential of Two Soils on Soybean Emergence 1

1979 ◽  
Vol 71 (6) ◽  
pp. 980-982 ◽  
Author(s):  
L. G. Heatherly ◽  
W. J. Russell
Keyword(s):  
Water Potential ◽  
Soil Water ◽  
Soil Water Potential
Sign in / Sign up

Export Citation Format

Share Document