Runoff modelling at two field slopes: use ofin situ measurements of air permeability to characterize spatial variability of saturated hydraulic conductivity

2004 ◽  
Vol 18 (5) ◽  
pp. 1009-1026 ◽  
Author(s):  
Bo V. Iversen ◽  
Per Moldrup ◽  
Per Loll
Keyword(s):  
Hydraulic Conductivity ◽  
Spatial Variability ◽  
Air Permeability ◽  
Saturated Hydraulic Conductivity

scholarly journals SPATIAL VARIABILITY OF THE SATURATED HYDRAULIC CONDUCTIVITY OF SOIL IN COCOA FARMING IN RECÔNCAVO BAIANO

2019 ◽  
Vol 32 (3) ◽  
pp. 786-794
Author(s):  
GERLANGE SOARES DA SILVA ◽  
JUCICLÉIA SOARES DA SILVA ◽  
FRANCISCO ADRIANO DE CARVALHO PEREIRA ◽  
RODRIGO ALMEIDA SANTANA ◽  
RAFAEL SILVA FIRMO ◽  
...  
Keyword(s):  
Hydraulic Conductivity ◽  
Spatial Variability ◽  
Irrigation Management ◽  
Gaussian Model ◽  
Constant Load ◽  
Saturated Hydraulic Conductivity ◽  
Limiting Factor ◽  
Site Management ◽  
Data Set ◽  
Different Depths

ABSTRACT Irrigated cocoa cultivation opened the way for production in Coastal Tablelands soils. However, in this region, the cohesive layer formed near the surface can be a limiting factor for production. The knowledge of physical soil water attributes enables the efficient irrigation management of cohesive soils. This study characterized and modeled the spatial variability of saturated hydraulic conductivity (K0) in a Distrocoeso Oxisoil of the Recôncavo Baiano Coastal Tablelands. The soil sampling was performed as undeformed structures from 50 spaced points in an 8.0 to 8.0 m area, at three different depths in the experimental area of the Federal University of Bahia Recôncavo in the Cruz das Almas-BA cultivated with cocoa (‘CCN 51’). In the laboratory, K0 was determined by permeameter method constant load, and the pore size distribution was determined using the voltage table and the soil density (Ds). Data were analyzed using descriptive statistics and geostatistics. On average, the K0 values were 40.41, 26.49, and 37.82 mm-1 h-1 at the depths from 0.0-0.15 m, 0.15-0.30, and 0.30-0.45 m. The Gaussian model was the best fit to the K0 data set. For soil class, the K0 showed a strong spatial dependence due to their relationship with the physical properties of the soil, its use, and handling. Since an important attribute for the delimitation of homogeneous areas for specific site management purposes as well be considered.

scholarly journals Prediction of biopore- and matrix-dominated flow from X-ray CT-derived macropore network characteristics

2016 ◽  
Vol 20 (10) ◽  
pp. 4017-4030 ◽  
Author(s):  
Muhammad Naveed ◽  
Per Moldrup ◽  
Marcel G. Schaap ◽  
Markus Tuller ◽  
Ramaprasad Kulkarni ◽  
...  
Keyword(s):  
Hydraulic Conductivity ◽  
Preferential Flow ◽  
Air Permeability ◽  
Saturated Hydraulic Conductivity ◽  
Soil Columns ◽  
Macropore Flow ◽  
Matric Potential ◽  
X Ray ◽  
Network Characteristics ◽  
Gas Diffusivity

Abstract. Prediction and modeling of localized flow processes in macropores is of crucial importance for sustaining both soil and water quality. However, currently there are no reliable means to predict preferential flow due to its inherently large spatial variability. The aim of this study was to investigate the predictive performance of previously developed empirical models for both water and air flow and to explore the potential applicability of X-ray computed tomography (CT)-derived macropore network characteristics. For this purpose, 65 cylindrical soil columns (6 cm diameter and 3.5 cm height) were extracted from the topsoil (5 cm to 8.5 cm depth) in a 15 m  ×  15 m grid from an agricultural field located in Silstrup, Denmark. All soil columns were scanned with an industrial X-ray CT scanner (129 µm resolution) and later employed for measurement of saturated hydraulic conductivity, air permeability at −30 and −100 cm matric potential, and gas diffusivity at −30 and −100 cm matric potential. Distribution maps for saturated hydraulic conductivity, air permeability, and gas diffusivity reflected no autocorrelation irrespective of soil texture and organic matter content. Existing empirical predictive models for saturated hydraulic conductivity and air permeability showed poor performance, as they were not able to realistically capture macropore flow. The tested empirical model for gas diffusivity predicted measurements at −100 cm matric potential reasonably well, but failed at −30 cm matric potential, particularly for soil columns with biopore-dominated flow. X-ray CT-derived macroporosity matched the measured air-filled porosity at −30 cm matric potential well. Many of the CT-derived macropore network characteristics were strongly interrelated. Most of the macropore network characteristics were also significantly correlated with saturated hydraulic conductivity, air permeability, and gas diffusivity. The predictive Ahuja et al. (1984) model for saturated hydraulic conductivity, air permeability, and gas diffusivity performed reasonably well when parameterized with novel, X-ray CT-derived parameters such as effective percolating macroporosity for biopore-dominated flow and total macroporosity for matrix-dominated flow. The obtained results further indicate that it is crucially important to discern between matrix-dominated and biopore-dominated flow for accurate prediction of macropore flow from X-ray CT-derived macropore network characteristics.

Spatial variability of saturated hydraulic conductivity at the hillslope scale: Understanding the role of land management and erosional effect

Geoderma ◽  
2015 ◽  
Vol 243-244 ◽  
pp. 58-68 ◽  
Author(s):  
Athanasios (Thanos) N. Papanicolaou ◽  
Mohamed Elhakeem ◽  
Christopher G. Wilson ◽  
C. Lee Burras ◽  
Larry T. West ◽  
...  
Keyword(s):  
Hydraulic Conductivity ◽  
Spatial Variability ◽  
Land Management ◽  
Saturated Hydraulic Conductivity ◽  
Hillslope Scale
Sign in / Sign up

Export Citation Format

Share Document