Below-ground relationships of soil texture, roots and hydraulic conductivity in two-phase mosaic vegetation in South-east Spain

2002 ◽  
Vol 52 (4) ◽  
pp. 535-553 ◽  
Author(s):  
N.A.L. Archer ◽  
J.N. Quinton ◽  
T.M. Hess
Keyword(s):  
Hydraulic Conductivity ◽  
Soil Texture ◽  
Two Phase ◽  
Below Ground ◽  
Mosaic Vegetation

Capillary pressure-dependent anisotropy of layered unsaturated soils

2010 ◽  
Vol 90 (2) ◽  
pp. 319-329 ◽  
Author(s):  
J. Zhu ◽  
D. Sun
Keyword(s):  
Hydraulic Conductivity ◽  
Transfer Function ◽  
Bulk Density ◽  
Capillary Pressure ◽  
Soil Texture ◽  
Unsaturated Soils ◽  
Particle Diameter ◽  
Hydraulic Parameters ◽  
Conductivity Anisotropy ◽  
Shape Factors

This paper presents an approach based on a conceptualization of combining the neural network based pedo-transfer function (PTF) results with the thin layer concept to explore capillary-pressure-dependent anisotropy in relation to soil texture and soil bulk density. The effects of capillary pressure (or saturation degree) on the hydraulic conductivity anisotropy of unsaturated soils are still poorly understood. The main objective is to examine how anisotropy characteristics are related to the relationships between hydraulic parameters and the basic soil attributes such as texture and bulk density. The hydraulic parameters are correlated with the texture and bulk density based on the pedo-transfer function (PTF) results. It is demonstrated that non-monotonic behavior of the unsaturated soil anisotropy in relation to the capillary pressure is only observed when the saturated hydraulic conductivity and the shape parameter are both related to the particle diameter. Therefore, it is suggested that this behavior is mainly due to the coupled dependence of the layer saturated hydraulic conductivities and the shape factors on the texture and bulk density. The results illustrate that the inter-relationships of soil texture, bulk density, and hydraulic properties may produce vastly different characteristics of anisotropic unsaturated soils.Key words: Anisotropy, unsaturated soils, capillary pressure-dependent

Soil texture controls vegetation biomass and organic carbon storage in arid desert grassland in the middle of Hexi Corridor region in Northwest China

Soil Research ◽  
2015 ◽  
Vol 53 (4) ◽  
pp. 366 ◽  
Author(s):  
Yongzhong Su ◽  
Jiuqiang Wang ◽  
Rong Yang ◽  
Xiao Yang ◽  
Guiping Fan
Keyword(s):  
Organic Carbon ◽  
Soil Texture ◽  
Clay Content ◽  
Northwest China ◽  
Hexi Corridor ◽  
Desert Grassland ◽  
Vegetation Biomass ◽  
Below Ground ◽  
The Mean ◽  
Arid Desert

Soil texture plays an important role in controlling vegetation production and soil organic carbon (SOC) concentration in arid desert grassland ecosystems. However, little is known about the occurrence and extent of these textural effects in the arid desert grasslands of Northwest China. This study used 160 soil profiles taken from 32 desert grassland sites in similar topographical units (alluvial–diluvial fans) in the middle of Hexi Corridor region of Northwest China to investigate vegetation biomass, SOC storage, and soil texture of seven layers in the top 100 cm of soil. The mean aboveground biomass, below-ground biomass, and total biomass in arid desert grassland were 155.3, 95.3, and 256.3 g m–2, respectively. More than 95% of the below-ground biomass was distributed in the top 30 cm of soil. Spatially, vegetation biomass was positively related to soil clay content and silt + clay content. The mean SOC density in the top 100 cm was 2.94 kg m–2 and ~46.8% of the storage was concentrated in the top 30 cm. SOC concentrations and stocks were positively and significantly related to clay content and silt + clay content in the seven soil layers sampled from the top 100 cm. The soil silt + clay content explained 42–79% of the variation in SOC stocks in the different soil depths. In conclusion, soil texture appears to be an important control on vegetation productivity and SOC capacity in arid Hexi Corridor desert grassland soils.

scholarly journals Effect of soil texture on water infiltration in semiarid reclaimed land

2015 ◽  
Vol 51 (1) ◽  
pp. 33-41 ◽  
Author(s):  
Wenmei Ma ◽  
Xingchang Zhang ◽  
Qing Zhen ◽  
Yanjiang Zhang
Keyword(s):  
Hydraulic Conductivity ◽  
Soil Properties ◽  
Soil Texture ◽  
Soil Depth ◽  
Water Infiltration ◽  
Empirical Coefficient ◽  
Reclaimed Land ◽  
Essential Information ◽  
Disturbed Land ◽  
Cumulative Infiltration

The infiltration of water and its influencing factors in disturbed or reclaimed land are not well understood. A better understanding would provide essential information for assessing the hydrological processes in disturbed ecosystems. We measured the infiltration of water in soils from loamy and sandy reclaimed land. The relationships between infiltration and soil properties were analyzed based on three models: the Kostiakov, Philip, and Green–Ampt equations. Our objectives were to understand water infiltration in reclaimed land with a variety of soil textures and to establish the dependence of water infiltration on soil properties. Both the rate of infiltration and the cumulative infiltration were higher in sandy than in loamy soils. The rate of infiltration and the cumulative infiltration decreased with soil depth in undisturbed land. The sorptivity rate (S) from the Philip equation, empirical coefficient (K) from the Kostiakov equation, and the satiated hydraulic conductivity (Ksl) from the Green–Ampt equation were 22%, 16%, and 7.1% higher, respectively, in sandy than in loamy soils. The Ksl increased significantly with Ks (saturated hydraulic conductivity) in both sandy and loamy soils. These indicated that the Green–Ampt equation can be used to describe Ks and the characteristics of infiltration for soils on disturbed land.

scholarly journals A global data set of soil hydraulic properties and sub-grid variability of soil water retention and hydraulic conductivity curves

2017 ◽  
Vol 9 (2) ◽  
pp. 529-543 ◽  
Author(s):  
Carsten Montzka ◽  
Michael Herbst ◽  
Lutz Weihermüller ◽  
Anne Verhoef ◽  
Harry Vereecken
Keyword(s):  
Hydraulic Conductivity ◽  
Soil Texture ◽  
Hydraulic Properties ◽  
Water Retention ◽  
Climate Models ◽  
Hydraulic Parameters ◽  
Soil Hydraulic Properties ◽  
Soil Water Retention ◽  
Data Set ◽  
Global Data

Abstract. Agroecosystem models, regional and global climate models, and numerical weather prediction models require adequate parameterization of soil hydraulic properties. These properties are fundamental for describing and predicting water and energy exchange processes at the transition zone between solid earth and atmosphere, and regulate evapotranspiration, infiltration and runoff generation. Hydraulic parameters describing the soil water retention (WRC) and hydraulic conductivity (HCC) curves are typically derived from soil texture via pedotransfer functions (PTFs). Resampling of those parameters for specific model grids is typically performed by different aggregation approaches such a spatial averaging and the use of dominant textural properties or soil classes. These aggregation approaches introduce uncertainty, bias and parameter inconsistencies throughout spatial scales due to nonlinear relationships between hydraulic parameters and soil texture. Therefore, we present a method to scale hydraulic parameters to individual model grids and provide a global data set that overcomes the mentioned problems. The approach is based on Miller–Miller scaling in the relaxed form by Warrick, that fits the parameters of the WRC through all sub-grid WRCs to provide an effective parameterization for the grid cell at model resolution; at the same time it preserves the information of sub-grid variability of the water retention curve by deriving local scaling parameters. Based on the Mualem–van Genuchten approach we also derive the unsaturated hydraulic conductivity from the water retention functions, thereby assuming that the local parameters are also valid for this function. In addition, via the Warrick scaling parameter λ, information on global sub-grid scaling variance is given that enables modellers to improve dynamical downscaling of (regional) climate models or to perturb hydraulic parameters for model ensemble output generation. The present analysis is based on the ROSETTA PTF of Schaap et al. (2001) applied to the SoilGrids1km data set of Hengl et al. (2014). The example data set is provided at a global resolution of 0.25° at https://doi.org/10.1594/PANGAEA.870605.

Evaluation of some selected soil properties of a drip irrigated tomato field at different moisture regimes in South-Western Nigeria

2021 ◽  
Vol 6 (2) ◽  
Author(s):  
E.O. Ogundipe
Keyword(s):  
Organic Matter ◽  
Hydraulic Conductivity ◽  
Soil Properties ◽  
Bulk Density ◽  
Soil Texture ◽  
Organic Matter Content ◽  
Infiltration Rate ◽  
Matter Content ◽  
Saturated Hydraulic Conductivity ◽  
Tomato Field

Soil properties are important to the development of agricultural crops. This study determined some selected soil properties of a drip irrigated tomato (Lycopersicon esculentum M.) field at different moisture regime in South-Western Nigeria. The experiment was carried out using Randomized Complete Block Design with frequency and depth of irrigation application as the main plot and sub-plot, respectively in three replicates. Three frequencies (7, 5 and 3 days) and three depths equivalent to 100, 75 and 50% of water requirement were used. Undisturbed and disturbed soil samples were collected from 0-5, 5-10, 10-20 and 20-30 cm soil layers for the determination of some soil properties (soil texture, organic matter content, bulk density, infiltration rate and saturated hydraulic conductivity) were determined using standard formulae. Soil Water Content (SWC) monitoring was conducted every two days using a gravimetric technique. The soil texture was sandy loam for all the soil depths; average value of soil organic matter was highest (1.8%) in the 0-5 cm surface layer and decreased with soil depth; the soil bulk density value before and after irrigation experiment ranged from 1.48 and 1.73 g/cm3 and 1.5 and 1.76 g/cm3, respectively; there was a rapid reduction in the initial infiltration and final infiltration rate. Saturated hydraulic conductivity show similar trend although the 20-30 cm layer had the lowest value (50.84 mm/h); the SWC affect bulk density during the growing season. The study showed that soil properties especially bulk density and organic matter content affect irrigation water movement at different depth..

Ability of Beijerinckia indica to degrade phenanthrene and reduce hydraulic conductivity

2010 ◽  
Vol 62 (12) ◽  
pp. 2953-2960 ◽  
Author(s):  
Dong-Hee Lim ◽  
Jai-Young Lee ◽  
Christian M. Lastoskie
Keyword(s):  
Hydraulic Conductivity ◽  
Electron Acceptor ◽  
Landfill Leachate ◽  
Rigid Wall ◽  
Soil Columns ◽  
Two Phase ◽  
Recovery Test ◽  
Phase Partitioning ◽  
Partitioning Bioreactor ◽  
Beijerinckia Indica

This study evaluates the ability of Beijerinckia indica (B. indica) as a biomaterial for aerobic biofilm barriers. B. indica's ability to remove phenanthrene was measured using a two-phase partitioning bioreactor. Approximately 500 mg/L of phenanthrene was gradually removed over a two week period under aerobic conditions of the bioreactor. B. indica's ability to reduce hydraulic conductivity was evaluated using rigid wall soil columns inoculated with the bacteria. B. indica formed a large quantity of strongly adhesive biofilm among soil particles, reducing the hydraulic conductivity in the soil columns by 2 or 3 orders of magnitude. To assess recovery of the biofilm, the formed biofilm was purposely destroyed by introducing landfill leachate into the soil columns. The biofilm recovery test showed that the hydraulic conductivity increased after leachate introduction. However, re-permeation of nutrient solution restored the permeability to its original lower value, which suggests a full recovery of the damaged biofilm. This study suggests that B. indica may be used as a possible biomaterial for aerobic biofilm barriers for the removal of phenanthrene from groundwater, provided that sufficient substrate and electron acceptor are provided to the treatment system.

Combine Empirical Equation with Experiment for Prediction of Soil Saturated Hydraulic Conductivity

2012 ◽  
Vol 518-523 ◽  
pp. 4815-4818
Author(s):  
Yan Wei Liu ◽  
Zhong Yuan Zhu
Keyword(s):  
Hydraulic Conductivity ◽  
Physicochemical Property ◽  
Soil Texture ◽  
Empirical Equation ◽  
Surface Soil ◽  
Graphical Representation ◽  
Research Area ◽  
Saturated Hydraulic Conductivity ◽  
Mean Square ◽  
Mean Square Errors

In order to improve simulation precision of saturated hydraulic conductivity, use RETC and PTFs function to simulate saturated hydraulic conductivity by measured research area surface soil (0-20cm) physicochemical property and soil texture data. The simulation results were assessed by the approach of consisting in presenting a graphical representation of model simulated compared with observed values and by mean square error. The main results indicate that the RETC-PTFs and local PTFs mean square errors are 1.19 and 0.40 respectively. The precision of RETC-PTFs is lower than local PTFs function obviously using soil physicochemical property and soil texture data. The RETC-PTFs is inappropriate to this area. Accuracy of each input data precision of RETC-PTFs play a big part in because of less data needed. More complete data not always get better simulating results.

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