scholarly journals Unsaturated Hydraulic Conductivity for Evaporation in Heterogeneous Soils

10.5772/16149 ◽  
2011 ◽  
Author(s):  
Dongmin Sun ◽  
Jianting Zhu
Keyword(s):  
Hydraulic Conductivity ◽  
Heterogeneous Soils ◽  
Unsaturated Hydraulic Conductivity

Unsaturated Hydraulic Conductivity of Structured Porous Media

2002 ◽  
Vol 1 (1) ◽  
pp. 14
Author(s):  
Markus Tuller ◽  
Dani Or
Keyword(s):  
Porous Media ◽  
Hydraulic Conductivity ◽  
Unsaturated Hydraulic Conductivity

Reevaluation of the Multistep Outflow Method for Determining Unsaturated Hydraulic Conductivity

2004 ◽  
Vol 3 (1) ◽  
pp. 317
Author(s):  
Haruyuki Fujimaki ◽  
Mitsuhiro Inoue
Keyword(s):  
Hydraulic Conductivity ◽  
Unsaturated Hydraulic Conductivity ◽  
Multistep Outflow

Reevaluation of the Multistep Outflow Method for Determining Unsaturated Hydraulic Conductivity

2003 ◽  
Vol 2 (3) ◽  
pp. 409 ◽  
Author(s):  
Haruyuki Fujimaki ◽  
Mitsuhiro Inoue
Keyword(s):  
Hydraulic Conductivity ◽  
Unsaturated Hydraulic Conductivity ◽  
Multistep Outflow

Simple Laboratory Measurement of Unsaturated Hydraulic Conductivity

1987 ◽  
Vol 113 (3) ◽  
pp. 405-412 ◽  
Author(s):  
Zohrab A. Samani ◽  
L. S. Willardson
Keyword(s):  
Hydraulic Conductivity ◽  
Laboratory Measurement ◽  
Unsaturated Hydraulic Conductivity

Predicting Unsaturated Hydraulic Conductivity from Soil Texture

1987 ◽  
Vol 113 (2) ◽  
pp. 184-197 ◽  
Author(s):  
Lynne Alexander ◽  
R. Wayne Skaggs
Keyword(s):  
Hydraulic Conductivity ◽  
Soil Texture ◽  
Unsaturated Hydraulic Conductivity

Hyphal colonization of Rhizophagus irregularis increases unsaturated hydraulic conductivity of a loamy sand distant from roots

2021 ◽  
Author(s):  
Michael Bitterlich ◽  
Richard Pauwels
Keyword(s):  
Hydraulic Conductivity ◽  
Water Content ◽  
Hydraulic Properties ◽  
Volumetric Water Content ◽  
Rhizophagus Irregularis ◽  
Loamy Sand ◽  
Soil Hydraulic Properties ◽  
Unsaturated Hydraulic Conductivity ◽  
Soil Hydraulic ◽  
Root Exclusion

<p>Hydraulic properties of mycorrhizal soils have rarely been reported and difficulties in directly assigning potential effects to hyphae of arbuscular mycorrhizal fungi (AMF) arise from other consequences of AMF being present, i.e. their influence on growth and water consumption rates of their host plants that both also influence soil hydraulic properties.</p><p>We assumed that the typical nylon meshes used for root-exclusion experiments in mycorrhizal research can provide a dynamic hydraulic barrier. It is expected that the uniform pore size of the rigid meshes causes a sudden hydraulic decoupling of the enmeshed inner volume from the surrounding soil as soon as the mesh pores become air-filled. Growing plants below the soil moisture threshold for hydraulic decoupling would minimize plant-size effects on root-exclusion compartments and allow for a more direct assignment of hyphal presence to modulations in soil hydraulic properties.</p><p>We carried out water retention and hydraulic conductivity measurements with two tensiometers introduced in two different heights in a cylindrical compartment (250 cm³) containing a loamy sand, either with or without the introduction of a 20 µm nylon mesh equidistantly between the tensiometers. Introduction of a mesh reduced hydraulic conductivity across the soil volumes by two orders of magnitude from 471 to 6 µm d<sup>-1</sup> at 20% volumetric water content.</p><p>We grew maize plants inoculated or not with Rhizophagus irregularis in the same soil in pots that contained root-exclusion compartments while maintaining 20% volumetric water content. When hyphae were present in the compartments, water potential and unsaturated hydraulic conductivity increased for a given water content compared to compartments free of hyphae. These differences increased with progressive soil drying.</p><p>We conclude that water extractability from soils distant to roots can be facilitated under dry conditions when AMF hyphae are present.</p><p> </p>

scholarly journals Deep subsoiling of a subsurface-compacted typical hapludult under citrus orchard

2013 ◽  
Vol 37 (4) ◽  
pp. 911-919 ◽  
Author(s):  
João Carlos Medeiros ◽  
Getulio Coutinho Figueiredo ◽  
Álvaro Luiz Mafra ◽  
Jaqueline Dalla Rosa ◽  
Sung Won Yoon
Keyword(s):  
Hydraulic Conductivity ◽  
Management Practices ◽  
Soil Management ◽  
Penetration Resistance ◽  
Soil Bulk Density ◽  
Soil Samples ◽  
Fruit Yield ◽  
Root Depth ◽  
Citrus Orchard ◽  
Unsaturated Hydraulic Conductivity

Soil management practices which increase the root depth penetration of citrus are important to the longevity and yield maintenance of this plant, especially in regions where long periods of drought are common, even in soil conventionally subsoiled to a depth of 30-40 cm, when the orchard was first established. The objective of this study was to evaluate the efficiency of subsoiling on the physical and hydric properties of a Typical Hapludult and fruit yield in a 14-year-old citrus orchard located in Piracicaba, SP. The treatments consisted of: no-subsoiling (with no tilling of the soil after the orchard was planted); subsoiling on one side of the plant lines (SUB. 1); and subsoiling on both sides of the plant lines (SUB. 2). The subsoiling treatments were carried out 1.5 m from the plant lines and to a depth of 0.8 m. Soil samples were taken 120 days after this operation, at four depths, in order to determine physical and hydric properties. Fruit yield was evaluated 150 days after subsoiling. Subsoiling between the plant lines of an old established citrus orchard alters the physical and hydric properties of the soil, which is reflected in increased soil macroporosity and unsaturated hydraulic conductivity, and reduced soil bulk density, critical degree-of-compactness and penetration resistance. The improvements in the physical and hydric properties of the soil were related to an increase in fruit number and orchard yield.

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