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 Influence of Drought on Foliar Water Uptake Capacity of Temperate Tree Species

Forests ◽  
2019 ◽  
Vol 10 (7) ◽  
pp. 562 ◽  
Author(s):  
Jeroen D.M. Schreel ◽  
Jonas S. von der Crone ◽  
Ott Kangur ◽  
Kathy Steppe
Keyword(s):  
Water Potential ◽  
Soil Water ◽  
Water Uptake ◽  
Tree Species ◽  
Soil Water Potential ◽  
Future Research ◽  
General Increase ◽  
Foliar Water Uptake ◽  
The Impact ◽  
Key Tree

Foliar water uptake (FWU) has been investigated in an increasing number of species from a variety of areas but has remained largely understudied in deciduous, temperate tree species from non-foggy regions. As leaf wetting events frequently occur in temperate regions, FWU might be more important than previously thought and should be investigated. As climate change progresses, the number of drought events is expected to increase, basically resulting in a decreasing number of leaf wetting events, which might make FWU a seemingly less important mechanism. However, the impact of drought on FWU might not be that unidirectional because drought will also cause a more negative tree water potential, which is expected to result in more FWU. It yet remains unclear whether drought results in a general increase or decrease in the amount of water absorbed by leaves. The main objectives of this study are, therefore: (i) to assess FWU-capacity in nine widely distributed key tree species from temperate regions, and (ii) to investigate the effect of drought on FWU in these species. Based on measurements of leaf and soil water potential and FWU-capacity, the effect of drought on FWU in temperate tree species was assessed. Eight out of nine temperate tree species were able to absorb water via their leaves. The amount of water absorbed by leaves and the response of this plant trait to drought were species-dependent, with a general increase in the amount of water absorbed as leaf water potential decreased. This relationship was less pronounced when using soil water potential as an independent variable. We were able to classify species according to their response in FWU to drought at the leaf level, but this classification changed when using drought at the soil level, and was driven by iso- and anisohydric behavior. FWU hence occurred in several key tree species from temperate regions, be it with some variability, which potentially allows these species to partly reduce the effects of drought stress. We recommend including this mechanism in future research regarding plant–water relations and to investigate the impact of different pathways used for FWU.

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.

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>

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

scholarly journals A Data-Driven Method for the Temporal Estimation of Soil Water Potential and Its Application for Shallow Landslides Prediction

Water ◽  
2021 ◽  
Vol 13 (9) ◽  
pp. 1208
Author(s):  
Massimiliano Bordoni ◽  
Fabrizio Inzaghi ◽  
Valerio Vivaldi ◽  
Roberto Valentino ◽  
Marco Bittelli ◽  
...  
Keyword(s):  
Machine Learning ◽  
Water Potential ◽  
Soil Water ◽  
Temporal Trends ◽  
Soil Water Potential ◽  
Shallow Landslides ◽  
Water Dynamics ◽  
Data Driven ◽  
Machine Learning Techniques ◽  
Physically Based

Soil water potential is a key factor to study water dynamics in soil and for estimating the occurrence of natural hazards, as landslides. This parameter can be measured in field or estimated through physically-based models, limited by the availability of effective input soil properties and preliminary calibrations. Data-driven models, based on machine learning techniques, could overcome these gaps. The aim of this paper is then to develop an innovative machine learning methodology to assess soil water potential trends and to implement them in models to predict shallow landslides. Monitoring data since 2012 from test-sites slopes in Oltrepò Pavese (northern Italy) were used to build the models. Within the tested techniques, Random Forest models allowed an outstanding reconstruction of measured soil water potential temporal trends. Each model is sensitive to meteorological and hydrological characteristics according to soil depths and features. Reliability of the proposed models was confirmed by correct estimation of days when shallow landslides were triggered in the study areas in December 2020, after implementing the modeled trends on a slope stability model, and by the correct choice of physically-based rainfall thresholds. These results confirm the potential application of the developed methodology to estimate hydrological scenarios that could be used for decision-making purposes.

NITROGEN TRANSFORMATIONS NEAR UREA IN SOIL WITH DIFFERENT WATER POTENTIALS

1988 ◽  
Vol 68 (3) ◽  
pp. 569-576 ◽  
Author(s):  
YADVINDER SINGH ◽  
E. G. BEAUCHAMP
Keyword(s):  
Water Potential ◽  
Soil Water ◽  
Incubation Period ◽  
Relative Rate ◽  
Soil Water Potential ◽  
Nitrification Inhibitor ◽  
Silt Loam ◽  
Nitrogen Transformations ◽  
Water Potentials ◽  
Initial Soil

Two laboratory incubation experiments were conducted to determine the effect of initial soil water potential on the transformation of urea in large granules to nitrite and nitrate. In the first experiment two soils varying in initial soil water potentials (− 70 and − 140 kPa) were incubated with 2 g urea granules with and without a nitrification inhibitor (dicyandiamide) at 15 °C for 35 d. Only a trace of [Formula: see text] accumulated in a Brookston clay (pH 6.0) during the transformation of urea in 2 g granules. Accumulation of [Formula: see text] was also small (4–6 μg N g−1) in Conestogo silt loam (pH 7.6). Incorporation of dicyandiamide (DCD) into the urea granule at 50 g kg−1 urea significantly reduced the accumulation of [Formula: see text] in this soil. The relative rate of nitrification in the absence of DCD at −140 kPa water potential was 63.5% of that at −70 kPa (average of two soils). DCD reduced the nitrification of urea in 2 g granules by 85% during the 35-d period. In the second experiment a uniform layer of 2 g urea was placed in the center of 20-cm-long cores of Conestogo silt loam with three initial water potentials (−35, −60 and −120 kPa) and the soil was incubated at 15 °C for 45 d. The rate of urea hydrolysis was lowest at −120 kPa and greatest at −35 kPa. Soil pH in the vicinity of the urea layer increased from 7.6 to 9.1 and [Formula: see text] concentration was greater than 3000 μg g−1 soil. There were no significant differences in pH or [Formula: see text] concentration with the three soil water potential treatments at the 10th day of the incubation period. But, in the latter part of the incubation period, pH and [Formula: see text] concentration decreased with increasing soil water potential due to a higher rate of nitrification. Diffusion of various N species including [Formula: see text] was probably greater with the highest water potential treatment. Only small quantities of [Formula: see text] accumulated during nitrification of urea – N. Nitrification of urea increased with increasing water potential. After 35 d of incubation, 19.3, 15.4 and 8.9% of the applied urea had apparently nitrified at −35, −60 and −120 kPa, respectively. Nitrifier activity was completely inhibited in the 0- to 2-cm zone near the urea layer for 35 days. Nitrifier activity increased from an initial level of 8.5 to 73 μg [Formula: see text] in the 3- to 7-cm zone over the 35-d period. Nitrifier activity also increased with increasing soil water potential. Key words: Urea transformation, nitrification, water potential, large granules, nitrifier activity, [Formula: see text] production

Sign in / Sign up

Export Citation Format

Share Document