Location of hydraulic resistance in the soil–plant pathway in seedlings of Pinussylvestris L. grown in peat

1986 ◽  
Vol 16 (1) ◽  
pp. 115-123 ◽  
Author(s):  
Göran Örlander ◽  
Karin Due
Keyword(s):  
Water Potential ◽  
Soil Water ◽  
Soil Water Potential ◽  
Dry Weight ◽  
Membrane System ◽  
Point Of View ◽  
Plant Water ◽  
Water Conductance ◽  
Dry Conditions ◽  
Total Dry Weight

Seedlings of Pinussylvestris L. were grown in three different soil media: 100% peat, 40% silt–60% peat, and 60% silt–40% peat. The percentages refer to total dry weight. Needle conductance, needle water potential, and plant water conductance were measured at different levels of soil water potentials controlled with a semipermeable membrane system. Seedlings grown in the 60:40 silt–peat mixture had a plant water conductance at a soil water potential of −0.1 MPa 3 times that of seedlings grown in pure peat. In an experiment where the roots were dipped in a silt slurry before planting, it was found that the plant water conductance at low soil water potential (−0.1 MPa) increased more than 2 times compared with undipped controls. We concluded that an important resistance to water flow in the soil–plant pathway was located in the soil outside the roots and probably was the most important resistance in the root–soil interface. The use of low humified peat as a growth medium is open to discussion from a silvicultural point of view because of its hydraulic properties under dry conditions.

Water relations of winter wheat. 5. The root system and osmotic adjustment in relation to crop evaporation

1984 ◽  
Vol 102 (2) ◽  
pp. 415-425 ◽  
Author(s):  
M. McGowan ◽  
P. Blanch ◽  
P. J. Gregory ◽  
D. Haycock
Keyword(s):  
Winter Wheat ◽  
Water Potential ◽  
Root System ◽  
Soil Water ◽  
Osmotic Adjustment ◽  
Stomatal Closure ◽  
Soil Water Potential ◽  
Plant Water ◽  
Potential Evaporation ◽  
Plant Water Potential

SummaryShoot and root growth and associated leaf and soil water potential relations were compared in three consecutive crops of winter wheat grown in the same field. Despite a profuse root system the crop grown in the second drought year (1976) failed to dry the soil as throughly as the crops in 1975 and 1977. Measurements of plant water potential showed that the restricted utilization of soil water reserves by this crop was associated with failure to make any significant osmotic adjustment, leading to premature loss of leaf turgor and stomatal closure. The implications of these results for models to estimate actual crop evaporation from values of potential evaporation are discussed.

Soil Moisture as Predictor of Plant Water Status

2021 ◽  
Vol 47 (3) ◽  
pp. 110-115
Author(s):  
Johannes Hertzler ◽  
Steffen Rust
Keyword(s):  
Water Potential ◽  
Soil Water ◽  
Water Status ◽  
Soil Water Potential ◽  
Irrigation Scheduling ◽  
Plant Water Status ◽  
Plant Water ◽  
Estimation Errors ◽  
Plant Available Water ◽  
The Relationship

Soil water potential can be used as a proxy for plant available water in irrigation scheduling. This study investigated the relationship between soil water potential and plant water status of pines (Pinus sylvestris L.) planted into two different substrates. Predawn leaf water potential as a well-established measure of the plant water status and soil water potential correlated very well. However, estimating the plant water status from individual sensor readings is subject to significant estimation errors. Furthermore, it was shown that heterogeneous soil/root ball combinations can lead to critical effects on the soil water balance, and that sensors installed outside of the root balls cannot estimate the plant water status without site-specific calibration.

scholarly journals Effects of Cultivar and Plant Spacing on the Seasonal Water Requirements of Highbush Blueberry

2007 ◽  
Vol 132 (2) ◽  
pp. 270-277 ◽  
Author(s):  
David R. Bryla ◽  
Bernadine C. Strik
Keyword(s):  
Soil Water ◽  
Water Use ◽  
Canopy Cover ◽  
Dry Weight ◽  
Vaccinium Corymbosum ◽  
High Density ◽  
Highbush Blueberry ◽  
Plant Water ◽  
Water Requirements ◽  
Total Dry Weight

Plant water requirements were investigated in three northern highbush blueberry (Vaccinium corymbosum L.) cultivars, Duke, Bluecrop, and Elliott, grown either at a high-density spacing of 0.45 m apart within rows or a more traditional spacing of 1.2 m. Spacing between rows was 3.0 m. As is typical for the species, each cultivar was shallow-rooted with most roots located less than 0.4 m deep, and each was sensitive to soil water deficits with plant water potentials declining as low as −1.6 MPa within 5 to 7 days without rain or irrigation. Compared with traditional spacing, planting at high density significantly reduced dry weight and yield of individual plants but significantly increased total dry weight and yield per hectare. High-density planting also significantly increased total canopy cover and water use per hectare. However, although canopy cover (often considered a factor in water use) increased up to 246%, water use never increased more than 10%. Because of more canopy cover at high density, less water penetrated the canopy during rain or irrigation (by overhead sprinklers), reducing both soil water availability and plant water potential in each cultivar and potentially reducing water use. Among cultivars, water use was highest in ‘Duke’, which used 5 to 10 mm·d−1, and lowest in ‘Elliott’, which used 3 to 5 mm·d−1. Peak water use in each cultivar was during fruit development, but water use after harvest declined sharply. Longer irrigation sets (i.e., longer run times) or alternative irrigation methods (e.g., drip) may be required when growing blueberry at high density, especially in cultivars with dense canopies such as ‘Elliott’.

scholarly journals Horizontal soil water potential heterogeneity: simplifying approaches for crop water dynamics models

2014 ◽  
Vol 11 (1) ◽  
pp. 1203-1252 ◽  
Author(s):  
V. Couvreur ◽  
J. Vanderborght ◽  
L. Beff ◽  
M. Javaux
Keyword(s):  
Analytical Solution ◽  
Winter Wheat ◽  
Water Potential ◽  
Soil Water ◽  
Soil Water Potential ◽  
Water Dynamics ◽  
Implicit Assumption ◽  
Plant Water ◽  
Row Crops ◽  
D Model

Abstract. Soil water potential (SWP) is known to affect plant water status, and even though observations demonstrate that SWP distribution around roots may limit plant water availability, its horizontal heterogeneity within the root zone is often neglected in hydrological models. As motive, using a horizontal discretisation significantly larger than one centimetre is often essential for computing time considerations, especially for large scale hydrodynamics models. In this paper, we simulate soil and root system hydrodynamics at the centimetre scale and evaluate approaches to upscale variables and parameters related to root water uptake (RWU) for two crop systems: a densely seeded crop with an average uniform distribution of roots in the horizontal direction (winter wheat) and a wide-row crop with lateral variations in root density (maize). In a first approach, the upscaled water potential at soil–root interfaces was assumed to equal the bulk SWP of the upscaled soil element. Using this assumption, the 3-D high resolution model could be accurately upscaled to a 2-D model for maize and a 1-D model for wheat. The accuracy of the upscaled models generally increased with soil hydraulic conductivity, lateral homogeneity of root distribution, and low transpiration rate. The link between horizontal upscaling and an implicit assumption on soil water redistribution was demonstrated in quantitative terms, and explained upscaling accuracy. In a second approach, the soil–root interface water potential was estimated by using a constant rate analytical solution of the axisymmetric soil water flow towards individual roots. In addition to the theoretical model properties, effective properties were tested in order to account for unfulfilled assumptions of the analytical solution: non-uniform lateral root distributions and transient RWU rates. Significant improvements were however only noticed for winter wheat, for which the first approach was already satisfying. This study confirms that the use of 1-D spatial discretisation to represent soil-plant water dynamics is a worthy choice for densely seeded crops. For wide-row crops, e.g. maize, further theoretical developments that better account for horizontal SWP heterogeneity might be needed in order to properly predict soil-plant hydrodynamics in 1-D.

scholarly journals Horizontal soil water potential heterogeneity: simplifying approaches for crop water dynamics models

2014 ◽  
Vol 18 (5) ◽  
pp. 1723-1743 ◽  
Author(s):  
V. Couvreur ◽  
J. Vanderborght ◽  
L. Beff ◽  
M. Javaux
Keyword(s):  
Analytical Solution ◽  
Winter Wheat ◽  
Water Potential ◽  
Soil Water ◽  
Soil Water Potential ◽  
Water Dynamics ◽  
Implicit Assumption ◽  
Plant Water ◽  
Row Crops ◽  
D Model

Abstract. Soil water potential (SWP) is known to affect plant water status, and even though observations demonstrate that SWP distribution around roots may limit plant water availability, its horizontal heterogeneity within the root zone is often neglected in hydrological models. As motive, using a horizontal discretisation significantly larger than one centimetre is often essential for computing time considerations, especially for large-scale hydrodynamics models. In this paper, we simulate soil and root system hydrodynamics at the centimetre scale and evaluate approaches to upscale variables and parameters related to root water uptake (RWU) for two crop systems: a densely seeded crop with an average uniform distribution of roots in the horizontal direction (winter wheat) and a wide-row crop with lateral variations in root density (maize). In a first approach, the upscaled water potential at soil–root interfaces was assumed to equal the bulk SWP of the upscaled soil element. Using this assumption, the 3-D high-resolution model could be accurately upscaled to a 2-D model for maize and a 1-D model for wheat. The accuracy of the upscaled models generally increased with soil hydraulic conductivity, lateral homogeneity of root distribution, and low transpiration rate. The link between horizontal upscaling and an implicit assumption on soil water redistribution was demonstrated in quantitative terms, and explained upscaling accuracy. In a second approach, the soil–root interface water potential was estimated by using a constant rate analytical solution of the axisymmetric soil water flow towards individual roots. In addition to the theoretical model properties, effective properties were tested in order to account for unfulfilled assumptions of the analytical solution: non-uniform lateral root distributions and transient RWU rates. Significant improvements were however only noticed for winter wheat, for which the first approach was already satisfying. This study confirms that the use of 1-D spatial discretisation to represent soil–plant water dynamics is a worthy choice for densely seeded crops. For wide-row crops, e.g. maize, further theoretical developments that better account for horizontal SWP heterogeneity might be needed in order to properly predict soil–plant hydrodynamics in 1-D.

Soil Water Potential and Bromacil Uptake by Wheat

Weed Science ◽  
1975 ◽  
Vol 23 (2) ◽  
pp. 127-130 ◽  
Author(s):  
J. D. Schreiber ◽  
V. V. Volk ◽  
L. Boersma
Keyword(s):  
Triticum Aestivum ◽  
Water Potential ◽  
Soil Water ◽  
Transpiration Rate ◽  
Soil Water Potential ◽  
Dry Weight ◽  
Silt Loam ◽  
High Concentration ◽  
Water Potentials ◽  
Application Rates

The uptake of14C labeled bromacil [5-bromo-3-sec-butyl-6-methyluracil] by wheat plants (Triticum aestivumL. ‘Gaines’) grown in a Woodburn silt loam was studied at soil water potentials of −0.35 and −2.50 bars, and in solutions containing 2.0 and 4.5μg/ml bromacil. Transpiration rate, shoot and root dry weight, and bromacil content were measured as a function of time. Bromacil uptake into the root and foliar portions of the wheat plants increased with time. At the low bromacil concentration, 70%, and at the high concentration, 42%, more bromacil was taken up by the plant at the higher soil water potential. Uptake of bromacil increased concurrently with increased transpiration of water. The bromacil concentration in the transpiration stream was greater at the −0.35 bar than at the −2.50 bar soil water potential at both bromacil application rates. Transpiration rates of the plants treated with bromacil were nearly the same after a 40-hr exposure at both soil water potentials. The rate of bromacil uptake and accumulation may be influenced by the effect of soil water potential on the apoplastic movement of water and solutes in the roots.

Soil Environment and Temperature Affect Germination and Seedling Growth of Mayweed Chamomile (Anthemis cotula)

1994 ◽  
Vol 8 (4) ◽  
pp. 668-672 ◽  
Author(s):  
David R. Gealy ◽  
Sheila A. Squier ◽  
Alex G. Ogg
Keyword(s):  
Water Potential ◽  
Soil Water ◽  
Seedling Growth ◽  
Soil Ph ◽  
Soil Water Potential ◽  
Soil Surface ◽  
Dry Weight ◽  
Nitrogen Fertilizers ◽  
Plant Weight ◽  
Total Plant

Mayweed chamomile is an increasing weed problem in cropping systems of the Pacific Northwest. Modern farming practices that utilize conservation tillage systems and heavy application of nitrogen fertilizers have been associated with increased soil surface water potential and decreased soil pH. Therefore, soil water potential, soil pH, and temperature effects on germination and growth of mayweed chamomile were determined in controlled laboratory tests. Germination of mayweed chamomile in soil was greatest at 30 C and a soil water potential of –25 kPa. Germination and seedling growth were similar in soils with pH 4.7, 5.1, and 6.2. Total plant weight was greatest at 20 C and reduced at 10 and 30 C. Shoot dry weight, as a percent of total dry weight, ranged from a low of 54% at 10 C to 78% at 30 C. A soil moisture potential of –10 000 kPa reduced germination and total plant weight by as much as 95% and 80%, respectively.

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