scholarly journals Community-specific hydraulic conductance potential of soil water decomposed for two Alpine grasslands by small-scale lysimetry

2018 ◽  
Vol 15 (4) ◽  
pp. 1065-1078 ◽  
Author(s):  
Georg Frenck ◽  
Georg Leitinger ◽  
Nikolaus Obojes ◽  
Magdalena Hofmann ◽  
Christian Newesely ◽  
...  
Keyword(s):  
Water Supply ◽  
Soil Water ◽  
Plant Community ◽  
Potential Evapotranspiration ◽  
Vegetation Type ◽  
Strong Increase ◽  
Small Scale ◽  
Alpine Grasslands ◽  
Water Conductance ◽  
Extreme Precipitation Events

Abstract. For central Europe in addition to rising temperatures an increasing variability in precipitation is predicted. This will increase the probability of drought periods in the Alps, where water supply has been sufficient in most areas so far. For Alpine grasslands, community-specific imprints on drought responses are poorly analyzed so far due to the sufficient natural water supply. In a replicated mesocosm experiment we compared evapotranspiration (ET) and biomass productivity of two differently drought-adapted Alpine grassland communities during two artificial drought periods divided by extreme precipitation events using high-precision small lysimeters. The drought-adapted vegetation type showed a high potential to utilize even scarce water resources. This is combined with a low potential to translate atmospheric deficits into higher water conductance and a lower biomass production as those measured for the non-drought-adapted type. The non-drought-adapted type, in contrast, showed high water conductance potential and a strong increase in ET rates when environmental conditions became less constraining. With high rates even at dry conditions, this community appears not to be optimized to save water and might experience drought effects earlier and probably more strongly. As a result, the water use efficiency of the drought-adapted plant community is with 2.6 gDW kg−1 of water much higher than that of the non-drought-adapted plant community (0.16 gDW kg−1). In summary, the vegetation's reaction to two covarying gradients of potential evapotranspiration and soil water content revealed a clear difference in vegetation development and between water-saving and water-spending strategies regarding evapotranspiration.

scholarly journals Community specific hydraulic conductance potential of soil water decomposed for two Alpine grasslands by small-scale lysimetry

2017 ◽  
Author(s):  
Georg Frenck ◽  
Georg Leitinger ◽  
Nikolaus Obojes ◽  
Magdalena Hofmann ◽  
Christian Newesely ◽  
...  
Keyword(s):  
Soil Water ◽  
Potential Evapotranspiration ◽  
Vegetation Type ◽  
Biomass Productivity ◽  
High Water ◽  
Small Scale ◽  
Alpine Grasslands ◽  
Vegetation Development ◽  
Water Conductance ◽  
Extreme Precipitation Events

Abstract. For Central Europe in addition to rising temperatures an increasing variability of precipitation is predicted. This will increase the probability of drought periods in the Alps, where water supply has been sufficient in most areas so far. For Alpine grasslands, community specific imprints on drought response are merely understood. In a replicated mesocosm experiment we compared evapotranspiration and biomass productivity of two differently drought-adapted vegetation communities during two artificial drought periods divided by extreme precipitation events using high precision small lysimeters. The drought adapted vegetation type showed a high potential to utilize even scarce water resources combined with a low potential to translate atmospheric deficits into higher water conductance with biomass production staying below those measured for the non-drought-adapted type. The non-drought-adapted type, in contrast, showed high water conductance potential with strongly increasing ET rates when environmental conditions became less constraining. With high rates even at dry conditions, this community appears not to be optimized to save water and might experience drought effects earlier and probably stronger. In summary, the vegetation’s reaction two co-varying gradients of potential evapotranspiration and soil water content revealed a clear difference of vegetation development and between water-saving and water-spending strategies regarding evapotranspiration.

scholarly journals Calculation of available water supply in crop root zone and the water balance of crops

2015 ◽  
Vol 45 (4) ◽  
pp. 285-298 ◽  
Author(s):  
Jan Haberle ◽  
Pavel Svoboda
Keyword(s):  
Water Balance ◽  
Water Supply ◽  
Soil Water ◽  
Root Zone ◽  
Potential Evapotranspiration ◽  
Pedotransfer Functions ◽  
Soil Water Retention ◽  
Available Water ◽  
Available Water Content ◽  
Access To Data

Abstract Determination of the water supply available in soils for crops is important for both the calculation of water balance and the prediction of water stress. An approach to calculations of available water content in layers of the root zone, depletion of water during growth, and water balance, with limited access to data on farms, is presented. Soil water retention was calculated with simple pedotransfer functions from the texture of soil layers, root depth, and depletion function were derived from observed data; and the potential evapotranspiration was calculated from the temperature. A comparison of the calculated and experimental soil water contents showed a reasonable fit.

Factors affecting the growth of kikuyu. II. Water supply

1988 ◽  
Vol 39 (1) ◽  
pp. 43
Author(s):  
GJ Murtagh
Keyword(s):  
Water Supply ◽  
Water Potential ◽  
Soil Water ◽  
Potential Evapotranspiration ◽  
Soil Water Potential ◽  
Field Measurements ◽  
Light Interception ◽  
Maintenance Respiration ◽  
Evaporative Demand ◽  
Factors Affecting

The influence of water supply on the growth of a kikuyu (Pennisetum clandestinum) pasture was estimated from field measurements of growth rate. A model was used to separate the confounded effects on growth of light interception, temperature, nitrogen and water supplies, and maintenance respiration. Water supply for growth was expressed as a function of both the soil water content and evaporative demand (potential evapotranspiration). The growth of kikuyu was very sensitive to water supply. On a wet soil (soil water potential > -20 kPa), an evaporative demand above 3.2 mm day-1 slowed growth. With optimum temperatures and a sward yield which gave the best balance between light interception and rate of maintenance respiration, a low evaporative demand of 2 mm day-1 reduced growth rates only when the soil water potential was less than - 134 kPa. However, with a medium-high evaporative demand of 5 mm day-1, growth was reduced by 39% on a wet soil, and ceased at a soil water potential of - 101 kPa.

A framework for quantifying water extraction and water stress responses of perennial lucerne

2009 ◽  
Vol 60 (8) ◽  
pp. 785 ◽  
Author(s):  
Hamish E. Brown ◽  
Derrick J. Moot ◽  
Andrew L. Fletcher ◽  
Peter D. Jamieson
Keyword(s):  
Water Stress ◽  
Water Supply ◽  
Soil Water ◽  
Stress Responses ◽  
Soil Profile ◽  
Potential Evapotranspiration ◽  
Soil Layer ◽  
Water Extraction ◽  
Crop Models ◽  
Wide Range

A generic framework was developed and validated for predicting the water extraction and water stress responses of perennial lucerne (Medicago sativa) to improve existing crop models. Perennial forages have roots established throughout a soil profile so require a different approach to quantify water extraction patterns than annual crops. Two years of experimental data from two fields in New Zealand, each containing dryland and irrigated lucerne crops, were analysed to develop the theory of the water extraction framework. This showed that the temporal pattern of water extraction was consistent and each year commenced in the shallowest layer and progressed downward. Water extraction from each soil layer was quantified as the minimum of soil water supply and crop demand for that layer. For each soil layer, water demand was represented by transpiration demand (the product of potential evapotranspiration and crop cover) minus the sum of water extraction in overlying layers. This approach gave accurate descriptions of water extraction patterns over a range of rainfall and irrigation situations. Water supply from each soil layer (l) was quantified as the product of plant-available water and an extraction rate constant (kll). The kll of lucerne could not be calculated using the traditional curve-fitting procedure so kll was calculated by integrating the water extraction framework described above with a soil water balance and fitting kll to minimise residuals for water extraction predictions in each soil layer. This gave kll values that decreased from 0.035/day in the 0–0.2 m layer of soil to 0.01/day in the deepest layer measured (1.8–2.3 m). The water extraction framework was validated against another 3 years of dryland and irrigated lucerne data and gave accurate predictions of water extraction patterns throughout the soil profile. Water stress was quantified from actual transpiration relative to transpiration demand (T/TD). The most sensitive variable was leaf area expansion, which decreased from an optimum at T/TD = 1 to zero at T/TD = 0.2, followed by radiation-use efficiency, which decreased from an optimum at T/TD = 1 to zero at a T/TD of zero. The framework for quantifying water extraction and the techniques determined for identifying appropriate parameters to measure and characterise the framework are expected to be generally applicable to perennial forages in a wide range of environments.

scholarly journals Exploring the growth response of Norway spruce (Picea abies) along a small-scale gradient of soil water supply

2018 ◽  
Vol 52 ◽  
pp. 123-130 ◽  
Author(s):  
Inken Rabbel ◽  
Burkhard Neuwirth ◽  
Heye Bogena ◽  
Bernd Diekkrüger
Keyword(s):  
Picea Abies ◽  
Water Supply ◽  
Soil Water ◽  
Norway Spruce ◽  
Growth Response ◽  
Small Scale

Where does the water come from? Variations in soil water uptake depth in a beech forest during the 2018 drought

2020 ◽  
Author(s):  
Arthur Geßler ◽  
Lukas Bächli ◽  
Kerstin Treydtre ◽  
Matthias Saurer ◽  
Matthias Häni ◽  
...  
Keyword(s):  
High Resolution ◽  
Water Supply ◽  
Soil Water ◽  
Water Uptake ◽  
In Situ Monitoring ◽  
Drought Period ◽  
Rainfall Events ◽  
Extreme Precipitation Events ◽  
Shallow Soil

<p>Water uptake under variable soil water supply is highly critical for the functioning of trees and the services provided by forests. Current climate projections predict an increasing variability of precipitation and thus a higher frequency of droughts alternating with extreme precipitation events. Reduced water availability is the most critical driver for tree mortality and impairment of trees’ functions. Under variable water supply, both the ability of a plant species to utilize remaining water under drought and to immediately capitalize on soil rewetting from subsequent rainfall events will be crucial for its survival and competitiveness. High uncertainty still exists regarding the ecohydrological belowground interactions at the soil–root interface on short to seasonal time scales.</p><p>To overcome previous limitations, we carried out high-resolution <em>in situ</em> observations of δ<sup>18</sup>O in soil and xylem water to track the water uptake of beech trees based on the approaches of Volkmann et al. (2016a & b) in the hot dry summer 2018. We set up a laser isotope system to continuously probe the δ<sup>18</sup>O signature in the water vapor in equilibrium with the soil water at different soil depths and with the xylem of beech trees in a forest in Switzerland and applied a Bayesian isotope mixing model (BIMM) to resolve the origin of the water taken up. Moreover, we installed xylem flow sensors, dendrometers and soil moisture sensors in the trees.</p><p>Mid of June the drought period started with extended phases of high temperature and only infrequent precipitation. At the same time, soil water content sharply decreased, especially in the upper soil layers and transpiration as well as radial growth started to decline, and this pattern became more pronounced until the end of August. In the soil water, strong <sup>18</sup>O enrichment in the upper 5 cm and slighter enrichment in 15 cm developed during this period. The BIMM results indicated that tree xylem water was made up by > 80% of shallow soil water (0-15 cm) at the onset of the drought and that this contribution continuously dropped to < 20% by the end of August, when deeper soil water and groundwater became more important. End of August, intensive rainfall events along with decreasing temperatures terminated the drought period when shallow soil water pools became partially replenished, and transpiration increased again. Within days, the contribution of shallow soil water to tree xylem water increased and reached a share of > 70% a couple of weeks after the end of the drought.  With the<em> in situ</em> method applied here, real-time information of the plasticity of soil water use becomes available and we can l trace the effect of drought and drought release on root activity of trees in different soil depths.</p><p> </p><p><strong>Volkmann THM, Haberer K, Gessler A, Weiler M. 2016a.</strong>High-resolution isotope measurements resolve rapid ecohydrological dynamics at the soil–plant interface. The New phytologist<strong>210</strong>: 839-849.</p><p><strong>Volkmann THM, Kühnhammer K, Herbstritt B, Gessler A, Weiler M. 2016b.</strong>A method for in situ monitoring of the isotope composition of tree xylem water using laser spectroscopy. Plant, Cell and Environment<strong>9</strong>: 2055–2063.</p>

scholarly journals Strong Modulation of Short Wind Waves and Ka-Band Radar Return Due to Internal Waves in the Presence of Surface Films. Theory and Experiment

2021 ◽  
Vol 13 (13) ◽  
pp. 2462
Author(s):  
Stanislav A. Ermakov ◽  
Irina A. Sergievskaya ◽  
Ivan A. Kapustin
Keyword(s):  
Phase Velocity ◽  
Internal Waves ◽  
Wind Waves ◽  
Strong Increase ◽  
Small Scale ◽  
Surface Films ◽  
Ka Band ◽  
Steady Current ◽  
Backscatter Modulation ◽  
Resonance Surface

Strong variability of Ka-band radar backscattering from short wind waves on the surface of water covered with surfactant films in the presence of internal waves (IW) was studied in wave tank experiments. It has been demonstrated that modulation of Ka-band radar return due to IW strongly depends on the relationship between the phase velocity of IW and the velocity of drifting surfactant films. An effect of the strong increase in surfactant concentration was revealed in convergent zones, associated with IW orbital velocities in the presence of a “resonance” surface steady current, the velocity of which was close to the IW phase velocity. A phenomenological model of suppression and modulations in the spectrum of small-scale wind waves due to films and IW was elaborated. It has been shown that backscatter modulation could not be explained by the modulation of free (linear) millimeter-scale Bragg waves, but was associated with the modulation of bound (parasitic) capillary ripples generated by longer, cm–dm-scale waves—a “cascade” modulation mechanism. Theoretical analysis based on the developed model was found to be consistent with experiments. Field observations which qualitatively illustrated the effect of strong modulation of Ka-band radar backscatter due to IW in the presence of resonance drift of surfactant films are presented.

Experiences with the practical implementation and operation of biological nitrification for a small-scale drinking water treatment plant

2016 ◽  
Vol 16 (4) ◽  
pp. 922-930 ◽  
Author(s):  
L. Richard ◽  
E. Mayr ◽  
M. Zunabovic ◽  
R. Allabashi ◽  
R. Perfler
Keyword(s):  
Drinking Water ◽  
Water Treatment ◽  
Water Supply ◽  
Treatment Plant ◽  
Drinking Water Treatment ◽  
Water Treatment Plant ◽  
Drinking Water Supply ◽  
Small Scale ◽  
Treatment Performance ◽  
Biological Nitrification

The implementation and evaluation of biological nitrification as a possible treatment option for the small-scale drinking water supply of a rural Upper Austrian community was investigated. The drinking water supply of this community (average system input volume: 20 m3/d) is based on the use of deep anaerobic groundwater with a high ammonium content of geogenic origin (up to 5 mg/l) which must be treated to prevent the formation of nitrites in the drinking water supply system. This paper describes the implementation and operation of biological nitrification despite several constraints including space availability, location and financial and manpower resources. A pilot drinking water treatment plant, including biological nitrification implemented in sand filters, was designed and constructed for a maximum treatment capacity of 1.2 m3/h. Online monitoring of selected physicochemical parameters has provided continuous treatment performance data. Treatment performance of the plant was evaluated under standard operation as well as in the case of selected malfunction events.

scholarly journals Environmental Performance of Small-Scale Seawater Reverse Osmosis Plant for Rural Area Water Supply

Membranes ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 40
Author(s):  
Latifah Abdul Ghani ◽  
Nora’aini Ali ◽  
Ilyanni Syazira Nazaran ◽  
Marlia M. Hanafiah
Keyword(s):  
Drinking Water ◽  
Global Warming ◽  
Water Supply ◽  
Reverse Osmosis ◽  
Resource Scarcity ◽  
Small Scale ◽  
Seawater Desalination ◽  
Seawater Reverse Osmosis ◽  
Desalination Technology ◽  
The Impact

Seawater desalination is an alternative technology to provide safe drinking water and to solve water issues in an area having low water quality and limited drinking water supply. Currently, reverse osmosis (RO) is commonly used in the desalination technology and experiencing significant growth. The aim of this study was to analyze the environmental impacts of the seawater reverse osmosis (SWRO) plant installed in Kampung Pantai Senok, Kelantan, as this plant was the first installed in Malaysia. The software SimaPro 8.5 together with the ReCiPe 2016 database were used as tools to evaluate the life cycle assessment (LCA) of the SWRO plant. The results showed that the impact of global warming (3.90 kg CO2 eq/year) was the highest, followed by terrestrial ecotoxicity (1.62 kg 1,4-DCB/year) and fossil resource scarcity (1.29 kg oil eq/year). The impact of global warming was caused by the natural gas used to generate the electricity, mainly during the RO process. Reducing the environmental impact can be effectively achieved by decreasing the electricity usage for the seawater desalination process. As a suggestion, electricity generation can be overcome by using a high-flux membrane with other suitable renewable energy for the plant such as solar and wind energy.

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