EFFECT OF CHANGING BULK DENSITY DURING WATER DESORPTION MEASUREMENT ON SOIL HYDRAULIC PROPERTIES

Soil Science ◽  
2004 ◽  
Vol 169 (5) ◽  
pp. 319-329 ◽  
Author(s):  
Dianqing Lu ◽  
Mingan Shao ◽  
Robert Horton ◽  
Chunping Liu
Keyword(s):  
Bulk Density ◽  
Hydraulic Properties ◽  
Soil Hydraulic Properties ◽  
Water Desorption ◽  
Soil Hydraulic

Root effects on soil water and hydraulic properties

Biologia ◽  
2007 ◽  
Vol 62 (5) ◽  
Author(s):  
Horst Gerke ◽  
Rolf Kuchenbuch
Keyword(s):  
Soil Moisture ◽  
Moisture Content ◽  
Water Content ◽  
Bulk Density ◽  
Soil Water ◽  
Soil Water Content ◽  
Hydraulic Properties ◽  
Soil Hydraulic Properties ◽  
Soil Hydraulic ◽  
Root Effects

AbstractPlants can affect soil moisture and the soil hydraulic properties both directly by root water uptake and indirectly by modifying the soil structure. Furthermore, water in plant roots is mostly neglected when studying soil hydraulic properties. In this contribution, we analyze effects of the moisture content inside roots as compared to bulk soil moisture contents and speculate on implications of non-capillary-bound root water for determination of soil moisture and calibration of soil hydraulic properties.In a field crop of maize (Zea mays) of 75 cm row spacing, we sampled the total soil volumes of 0.7 m × 0.4 m and 0.3 m deep plots at the time of tasseling. For each of the 84 soil cubes of 10 cm edge length, root mass and length as well as moisture content and soil bulk density were determined. Roots were separated in 3 size classes for which a mean root porosity of 0.82 was obtained from the relation between root dry mass density and root bulk density using pycnometers. The spatially distributed fractions of root water contents were compared with those of the water in capillary pores of the soil matrix.Water inside roots was mostly below 2–5% of total soil water content; however, locally near the plant rows it was up to 20%. The results suggest that soil moisture in roots should be separately considered. Upon drying, the relation between the soil and root water may change towards water remaining in roots. Relations depend especially on soil water retention properties, growth stages, and root distributions. Gravimetric soil water content measurement could be misleading and TDR probes providing an integrated signal are difficult to interpret. Root effects should be more intensively studied for improved field soil water balance calculations.

scholarly journals Modeling the Impact of Rhizosphere Bulk Density and Mucilage Gradients on Root Water Uptake

2021 ◽  
Vol 3 ◽  
Author(s):  
Magdalena Landl ◽  
Maxime Phalempin ◽  
Steffen Schlüter ◽  
Doris Vetterlein ◽  
Jan Vanderborght ◽  
...  
Keyword(s):  
Bulk Density ◽  
Water Uptake ◽  
Hydraulic Properties ◽  
Model Simulation ◽  
Root Water Uptake ◽  
Water Dynamics ◽  
Bulk Soil ◽  
Soil Hydraulic Properties ◽  
Soil Hydraulic ◽  
The Impact

In models of water flow in soil and roots, differences in the soil hydraulic properties of the rhizosphere and the bulk soil are usually neglected. There is, however, strong experimental evidence that rhizosphere and bulk soil hydraulic properties differ significantly from each other due to various root-soil interaction processes. Two such processes, which can also influence each other, are rhizosphere loosening or compaction and mucilage deposition. In this work, we identified realistic gradients in rhizosphere bulk density and mucilage concentration using X-ray CT imaging, respectively, model simulation for two different soil types and soil bulk densities and related them to soil hydraulic parameters. Using a 1D-single-root model, we then evaluated both the individual and combined effects of these gradients on soil water dynamics using scenario simulations. We showed that during soil drying, a lower rhizosphere bulk density leads to an earlier onset of water stress and to a reduced root water uptake that is sustained longer. The presence of mucilage led to a faster reduction of root water uptake. This is due to the stronger effect of mucilage viscosity on hydraulic conductivity compared to the mucilage- induced increase in water retention. Root water uptake was rapidly reduced when both mucilage and rhizosphere bulk density gradients were considered. The intensity of the effect of gradients in rhizosphere bulk density and mucilage concentration depended strongly on the interplay between initial soil hydraulic conditions, soil type and soil bulk densities. Both gradients in rhizosphere bulk density and mucilage concentration appear as a measure to sustain transpiration at a lower level and to avoid fast dehydration.

scholarly journals Soil Hydraulic Properties in a Cassava Field as a Function of Soil Dry Bulk Density

2005 ◽  
Vol 18 (2) ◽  
pp. 156-166 ◽  
Author(s):  
Osama MOHAWESH ◽  
Kazunari FUKUMURA ◽  
Tomoyasu ISHIDA ◽  
Kunihiko YOSHINO
Keyword(s):  
Bulk Density ◽  
Hydraulic Properties ◽  
Soil Hydraulic Properties ◽  
Soil Hydraulic

scholarly journals An Analysis of Hydraulic Properties of Soil Based on Soil Texture in Chiti Areas of Lamjung District In Nepal

2018 ◽  
Vol 11 ◽  
pp. 63-76
Author(s):  
Jyoti Karki ◽  
Umesh Kumar Mandal ◽  
Chabi Lal Chidi ◽  
Jitan Dahal ◽  
Narendra Raj Khanal ◽  
...  
Keyword(s):  
Land Use ◽  
Land Cover ◽  
Bulk Density ◽  
Soil Texture ◽  
Hydraulic Properties ◽  
Land Use Land Cover ◽  
Soil Hydraulic Properties ◽  
Barren Land ◽  
Land Use Types ◽  
Soil Hydraulic

Soil hydraulic properties play crucial role for having sustainable growth of vegetation and also required for carrying out environmental studies especially subsurface ground water. Since, its direct measurement is time consuming and therefore costly, indirect methods such as pedotransfer functions have been used to estimate hydraulic properties. Soil hydraulic properties: bulk density, available water, permanent wilting point, field capacity and water retention capacity and saturated hydraulic conductivity are essential to be studied. These factors affect soil productivity and the environment. The knowledge of soil water properties for different land-use and land cover types based on soil textural classes are important for re-growth of plants and agriculture crops and ultimately efficient soil and water management. The aim of this paper is to measure soil hydraulic properties based on soil textural classes for different land use types. Furthermore, the use of the soil texture triangle: hydraulic properties calculator has been assessed. The comparison of the soil hydraulic properties obtained from textural triangle for different land use land and cover types has also been analyzed. Moreover, an analysis of variance (ANOVA) of soil hydraulic properties among different land use types has been performed. The soil reaction (pH) value ranges from 4.69 to 6.69 and as a mean of 5.51 indicating slight acidic. The analysis showed barren land occupying 14.3 percent of total land use/land cover is found to be suitable for plant growth since it has loam texture having bulk density less than 1.6 g/cm3.The analysis of bulk density showed that barren land is significantly different at the 0.05 level from both agriculture and forest, whereas agriculture and forests  are not different even at 0.05 significant levels. It verifies the fact that mean bulk density at the depth of 0.15 cm is affected by land use land cover types.The Geographical Journal of NepalVol. 11: 63-76, 2018

A modified upward infiltration method for characterizing soil hydraulic properties

2002 ◽  
Vol 66 (1) ◽  
pp. 57 ◽  
Author(s):  
M. H. Young ◽  
A. Karagunduz ◽  
J. Šimůnek ◽  
K. D. Pennell
Keyword(s):  
Hydraulic Properties ◽  
Soil Hydraulic Properties ◽  
Soil Hydraulic ◽  
Infiltration Method

scholarly journals Pinhole Multistep Centrifuge Outflow Method for Estimating Unsaturated Hydraulic Properties with Small Volume Soil Samples

Water ◽  
2021 ◽  
Vol 13 (9) ◽  
pp. 1169
Author(s):  
Long Thanh Bui ◽  
Yasushi Mori
Keyword(s):  
Hydraulic Properties ◽  
Volcanic Ash ◽  
Small Volume ◽  
Clayey Soil ◽  
Soil Hydraulic Properties ◽  
Retention Curve ◽  
Volcanic Ash Soil ◽  
Equilibrium Data ◽  
Soil Hydraulic ◽  
Water Holding

If soil hydraulic conductivity or water holding capacity could be measured with a small volume of samples, it would benefit international fields where researchers can only carry a limited amount of soils out of particular regions. We performed a pinhole multistep centrifuge outflow method on three types of soil, which included granite decomposed soil (Masa soil), volcanic ash soil (Andisol soil), and alluvial clayey soil (paddy soil). The experiment was conducted using 2 mL and 15 mL centrifuge tubes in which pinholes were created on the top and bottom for air intrusion and outflow, respectively. Water content was measured at 5, 15, and 30 min after applying the centrifuge to examine the equilibrium time. The results showed that pinhole drainage worked well for outflow, and 15 or 30 min was sufficient to obtain data for each step. Compared with equilibrium data, the retention curve was successfully optimized. Although the curve shape was similar, unsaturated hydraulic conductivities deviated largely, which implied that Ks caused convergence issues. When Ks was set as a measured constant, the unsaturated hydraulic properties converged well and gave excellent results. This method can provide soil hydraulic properties of regions where soil sampling is limited and lacks soil data.

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