Root Growth, Water Uptake and Canopy Development in Eucalyptus viminalis Seedlings

1994 ◽  
Vol 21 (1) ◽  
pp. 69 ◽  
Author(s):  
JG Phillips ◽  
SJ Riha
Keyword(s):  
Root Growth ◽  
Water Potential ◽  
Soil Water ◽  
Water Loss ◽  
Soil Water Potential ◽  
Water Extraction ◽  
Soil Conditions ◽  
Lower Section ◽  
Canopy Development ◽  
Eucalyptus Viminalis

A split-root experiment was conducted using Eucalyptus viminalis seedlings which were exposed to three watering regimes in order to investigate root growth and soil water extraction under conditions of a drying soil profile. Seedlings were grown in columns in which the soil was divided horizontally with a soft wax plate. Watering treatments were composed of (1) both upper and lower sections of the column well watered (W/W), (2) only the lower section well watered (D/W), and (3) water withheld completely from both upper and lower sections (D/D). Daily measurements included soil water potential (Ψs), column water loss and leaf elongation. Increase in above- and below-ground biomass was deter- mined from initial and final harvests after 25 days of treatment. Whole-column water loss and leaf extension were depressed as Ψs in the upper section of D/W and D/D decreased to -0.4 MPa over the first 8-10 days. However, water loss did not decrease significantly in the lower section of treatment D/W relative to the lower section of treatment W/W during this period. This indicated that water extraction by roots remaining in wet soil was not severely inhibited by the decrease in transpiration associated with the soil conditions in the upper profile. Root distribution at the end of the experiment indicated significant growth in the lower section of treatment D/W. There was evidence that hydraulic lifting of water between column sections may have occurred, as periodic increases in soil water potential of the unwatered upper section of D/W were observed.

scholarly journals Microbial extracellular polysaccharide production and aggregate stability controlled by Switchgrass (Panicum virgatum) root biomass and soil water potential

2019 ◽  
Author(s):  
Yonatan Sher ◽  
Nameer R. Baker ◽  
Don Herman ◽  
Christina Fossum ◽  
Lauren Hale ◽  
...  
Keyword(s):  
Water Potential ◽  
Soil Water ◽  
Root Biomass ◽  
Soil Aggregates ◽  
Soil Water Potential ◽  
Aggregate Stability ◽  
Biofuel Production ◽  
Soil Conditions ◽  
Diurnal Changes ◽  
Marginal Soils

ABSTRACTDeep-rooting perennial grasses are promising feedstock for biofuel production, especially in marginal soils lacking organic material, nutrients, and/or that experience significant water stress. Perennial grass roots can alter surrounding soil conditions and influence microbial activities, particularly the production of extracellular polymeric substances composed primarily of extracellular polysaccharides (EPS). These polymers can alleviate cellular moisture and nutrient stress, and enhance soil characteristics through improved water retention and aggregate stability, the latter of which may in turn enhance carbon persistence. In this study we used a 13CO2 tracer greenhouse experiment to examine the effect of switchgrass cultivation on the production and origin of EPS in a marginal soil with five fertilization/water treatments (control, +N, +NP, +P, low water). Soils with both added nitrogen and phosphorus had the highest root biomass, EPS and percentage of water-stable soil aggregates. Multiple linear regression analyses revealed root biomass was the most important determinant for soil EPS production, potentially by controlling carbon supply and diurnal changes in soil water potential. Path analysis highlighted the role of soil water potential were and EPS on with water-stable soil aggregates, indicating that EPS concentration and soil aggregation have similar drivers in this soil. High mannose content confirmed the microbial origin of EPS. 13CO2 labeling indicated that 0.18% of newly fixed plant carbon was incorporated into EPS. Analysis of field samples suggests that EPS is significantly enhanced under long-term switchgrass cultivation. Our results demonstrate that switchgrass cultivation can promote microbial production of EPS, providing a mechanism to enhance sustainability of marginal soils.

scholarly journals Sensor placement for soil water monitoring in lemon irrigated by micro sprinkler

2007 ◽  
Vol 11 (1) ◽  
pp. 46-52 ◽  
Author(s):  
Eugênio F. Coelho ◽  
Delfran B. dos Santos ◽  
Carlos A. V. de Azevedo
Keyword(s):  
Water Potential ◽  
Water Content ◽  
Soil Water ◽  
Root Length ◽  
Sensor Placement ◽  
Soil Water Potential ◽  
Water Extraction ◽  
Soil Profiles ◽  
Water Sensor ◽  
Root Water Extraction

This research had as its objective the investigation of an alternative strategy for soil sensor placement to be used in citrus orchards irrigated by micro sprinkler. An experiment was carried out in a Tahiti lemon orchard under three irrigation intervals of 1, 2 and 3 days. Soil water potential, soil water content distribution and root water extraction were monitored by a time-domain-reflectometry (TDR) in several positions in soil profiles radial to the trees. Root length and root length density were determined from digital root images at the same positions in the soil profiles where water content was monitored. Results showed the importance of considering root water extraction in the definition of soil water sensor placement. The profile regions for soil water sensor placement should correspond to the intersection of the region containing at least 80% of total root length and the region of at least 80% of total water extraction. In case of tensiometers, the region of soil water potential above -80 kPa should be included in the intersection.

scholarly journals `Ben Lear' and `Stevens' Cranberry Root and Shoot Growth Response to Soil Water Potential

HortScience ◽  
2005 ◽  
Vol 40 (3) ◽  
pp. 795-798 ◽  
Author(s):  
Dana L. Baumann ◽  
Beth Ann Workmaster ◽  
Kevin R. Kosola
Keyword(s):  
Root Growth ◽  
Water Potential ◽  
Soil Water ◽  
Leaf Area ◽  
Growth Rates ◽  
Soil Water Potential ◽  
Relative Growth ◽  
Relative Growth Rates ◽  
Water Potentials ◽  
Whole Plant

Wisconsin cranberry growers report that fruit production by the cranberry cultivar `Ben Lear' (Vaccinium macrocarpon Ait.) is low in beds with poor drainage, while the cultivar `Stevens' is less sensitive to these conditions. We hypothesized that `Ben Lear' and `Stevens' would differ in their root growth and mortality response to variation in soil water potential. Rooted cuttings of each cultivar were grown in a green-house in sand-filled pots with three different soil water potentials which were regulated by a hanging water column below a fritted ceramic plate. A minirhizotron camera was used to record root growth and mortality weekly for five weeks. Root mortality was negligible (2% to 6%). Whole plant relative growth rates were greatest for both cultivars under the wettest conditions. Rooting depth was shallowest under the wettest conditions. Whole-plant relative growth rates of `Ben Lear' were higher than `Stevens' at all soil water potentials. `Stevens' plants had significantly higher root to shoot ratios and lower leaf area ratios than `Ben Lear' plants, and produced more total root length than `Ben Lear' at all soil water potentials. Shallow rooting, high leaf area ratio, and low allocation to root production by `Ben Lear' plants may lead to greater susceptibility to drought stress than `Stevens' plants in poorly drained cranberry beds.

EFFECTS OF SUBSOIL BULK DENSITY, NUTRIENT AVAILABILITY AND SOIL MOISTURE ON CORN ROOT GROWTH IN THE FIELD

1987 ◽  
Vol 67 (2) ◽  
pp. 293-308 ◽  
Author(s):  
M. STYPA ◽  
A. NUNEZ-BARRIOS ◽  
D. A. BARRY ◽  
M. H. MILLER ◽  
W. A. MITCHELL
Keyword(s):  
Root Growth ◽  
Water Potential ◽  
Bulk Density ◽  
Soil Water ◽  
Soil Water Potential ◽  
Soil Bulk Density ◽  
Corn Root ◽  
Penetrometer Resistance ◽  
Loam Soil ◽  
Distribution Of Roots

In a 4-yr study, root growth in the upper 50 cm of a silt loam soil (Gleyed Melanic Brunisol) was equal to or greater than that in a low-density artificial medium (soil:peat:perlite) in spite of a high bulk density in the soil (1.5 Mg m−3 in the 15-to 45-cm depth). We suggest that, due to the natural structure of the Bm horizon, the resistance to root growth is much less than would be expected from bulk density or penetrometer resistance measurements. Marked increases in P and K fertility in the surface soil had only minor effects on either the total length or distribution of roots although the shoot growth was markedly increased. Neither total root length nor root distribution were altered by irrigation during 1981, the only year a moisture variable was included. During a 2-wk dry period in July, prior to anthesis, soil water potential on the nonirrigated plots decreased to −1.5 MPa in the upper 15 cm and to −0.5 MPa in the 15- to 30-cm layer. Leaf water potential, stomatal conductance and rate of growth during the period were lower on the nonirrigated treatment although final dry matter production was not. The results indicate that corn root growth and distribution in the field are not as sensitive to environmental factors as one would expect from short-term laboratory studies. Key words: Corn, root growth, soil bulk density, fertility, soil water

Influence of soil water potential and mycorrhizal colonization on root growth of yellow-poplar and sweet gum seedlings grown in compacted soil

1988 ◽  
Vol 18 (11) ◽  
pp. 1392-1396 ◽  
Author(s):  
G. L. Simmons ◽  
P. E. Pope
Keyword(s):  
Root Growth ◽  
Water Potential ◽  
Bulk Density ◽  
Soil Water ◽  
Root Length ◽  
Soil Water Potential ◽  
Mechanical Resistance ◽  
Yellow Poplar ◽  
Greenhouse Study ◽  
Water Potentials

A greenhouse study was conducted to determine the influence of soil water potential and endomycorrhizal fungi on root growth of yellow-poplar (Liriodendrontulipifera L.) and sweet gum (Liquidambarstyraciflua L.) seedlings grown at three soil bulk densities. Silt loam soil was compacted in PVC pots to bulk densities of 1.25 (low), 1.40 (medium), or 1.55 (high) Mg • m−3, and equilibrated at −10 kPa soil water potential. Newly germinated seedlings were transplanted into the pots, inoculated with fungal chlamydospores of Glomusmacrocarpum or Glomusfasciculaturn, or distilled water (control), and grown for 3 months at −10 or −300 kPa soil water potential. Total porosity, air-filled porosity, water content, and mechanical resistance of the soil were determined for samples compacted to the same bulk densities and equilibrated at the same soil water potentials as were used in the greenhouse study. Root growth was reduced by the high mechanical resistance caused by bulk densities of 1.40 and 1.55 Mg • m−3 at −300 kPa water potential. At both water potentials, total length of lateral roots and fibrosity of the root system of both tree species decreased significantly when bulk density increased from 1.40 to 1.55 Mg • m−3. Air-filled porosity less than 0.12 m3 • m−3 limited root growth when water potential was −10 kPa, and mechanical resistance greater than 3438 kPa restricted growth at −300 kPa. At −10 kPa, root length and fibrosity were greatest for inoculated sweet gum seedlings at each bulk density. At −300 kPa, sweet gum seedlings inoculated with G. fasciculatum had the greatest root length and fibrosity at the low and medium bulk densities. Mycorrhizal effects on root length of yellow-poplar were variable, and fibrosity was not significantly affected by mycorrhizal treatment.

scholarly journals Effects of wood ash and soil water potential on vegetative development of mung bean (Vigna radiata L.)

2021 ◽  
pp. 354-361
Author(s):  
Luana Glaup Araujo Dourado ◽  
Edna Maria Bonfim- Silva ◽  
Tonny José Araújo da Silva ◽  
Everton Alves Rodrigues Pinheiro ◽  
William Fenner
Keyword(s):  
Plant Growth ◽  
Water Potential ◽  
Soil Water ◽  
Vigna Radiata ◽  
Mung Bean ◽  
Soil Water Potential ◽  
Wood Ash ◽  
Soil Conditions ◽  
Experimental Conditions ◽  
Mato Grosso

This research aimed to evaluate the amending potential of eucalyptus’s wood ash on soil chemical properties and soil-water potential. The experiment was conducted in a greenhouse at the Federal University of Mato Grosso, campus in Rondonópolis. The experimental design was composed of randomized blocks in a 5x5 factorial scheme, including five soil-water potentials (‒4, ‒8, ‒16, ‒32 and ‒64 kPa), and five wood ash doses (0; 8; 16; 24 and 32 g dm-3). The soil samples were collected from the top layer of an Oxisol under natural Cerrado vegetation. Mung bean (Vigna radiata L.) growth variables (plant height, numbers of leaves, stem diameter, and SPAD index) were analyzed at three different phenological periods. In general, the wood ash doses increased soil pH, eliminated the exchangeable aluminum, and improved soil essential nutrients availability. As a result, mung bean plants responded positively to wood ash, achieving superior results at doses ranging from 24 to 26 g dm-3. The interaction between wood ash doses and soil water potential was not significant. However, drier soil conditions constrained plant growth severely. According to our experimental conditions, plant growth variables achieved higher performance at soil water potential of -4 kPa

scholarly journals Maize nodal root growth under water deficits

2016 ◽  
Author(s):  
◽  
Kara J. Riggs
Keyword(s):  
Root Growth ◽  
Water Potential ◽  
Root System ◽  
Soil Water ◽  
Soil Water Potential ◽  
Experimental System ◽  
Root Tip ◽  
Growth Responses ◽  
Water Potentials ◽  
Nodal Root

The nodal root system is critical for the development of the mature root system in maize (Zea mays L.) and other grasses. Under drought conditions, nodal root axes may need to grow through surface soil that is dry, hard, and hot. These roots are known to have a superior ability to continue elongation at low water potentials relative to other organs of the plant, but the physiology of this response has been little studied. The objective of this study was to develop an experimental system that models the field situation in which upper soil layers dry, to enable studies of nodal root growth regulation under water deficit conditions. A divided-chamber experimental system was developed to allow the growth of maize primary and seminal root systems in well-watered conditions while the nodal root system is exposed to precise conditions of low soil water potential. The divided-chamber system was used to characterize nodal root growth responses to a range of soil water potentials under steady-state and reproducible conditions. Two contrasting genotypes, selected for differences in root growth response to water stress based on a previous study of the primary root, displayed similarly sensitive growth responses to -0.3 MPa soil, but different capacities to maintain high root tip water potential corresponding with different growth responses at lower soil water potentials. Both genotypes maintained relatively high nodal root tip water potentials in -2.0 MPa soil, despite the decreased soil water potential, suggesting a stress-induced response that enhances water transport to the root tip. The difference in high tissue water potential maintenance was seen not only between the contrasting genotypes but also between the first two developmental nodes of roots. The divided-chamber system provides a powerful experimental approach to investigate the physiological mechanisms regulating nodal root growth responses to adverse soil conditions. Future studies may include measurements of hydraulic conductivity, anatomical characterization of vascular elements near the growth zone, aquaporin content and activity, and suberin deposition in response to low soil water potentials.

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
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