Influence of soil, land use and climatic factors on the hydraulic conductivity of soil (original) (raw)
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Estimation of Saturated Hydraulic Conductivity from Soil Morphological and Genetic Information
Soil Science Society of America Journal, 1981
Since laboratory and field measurement of soil hydraulic properties is time consuming and subject to large error, numerous models have been proposed to predict soil hydraulic properties from easily measurable soil properties such as particle size distribution, bulk density, effective porosity and carbon content. In this study a multiple linear regression model was developed to predict the saturated hydraulic conductivity of soils from their particle size distribution and bulk density data. Published data from 350 soil core samples of varying soils from different sources were used to develop the model. Stepwise regression selected the best model for prediction of soil hydraulic conductivity (R2 = 0.68, P < 0.0001) from the independent parameters of silt, clay, and bulk density. Additional field measured data were collected to test and validate the model using several statistical evaluation procedures. Based on the statistical evaluation criteria, the model performed fairly well and gave a satisfactory validation versus the field measured data. KEYWORDS.
Indirect estimation of near-saturated hydraulic conductivity from readily available soil information
Geoderma, 2002
Application of process-based water flow and solute transport models is often hampered by insufficient knowledge of soil hydraulic properties. This is certainly true for dual-or multi-porosity models that account for non-equilibrium flow of water in macropores, where the saturated 'matrix' hydraulic conductivity is a particularly critical parameter. Direct measurement is possible, but this is impractical for larger scale studies (i.e. catchment or regional), where estimation methods (pedotransfer functions) are usually required. This paper presents pedotransfer functions for hydraulic conductivity at a pressure head of À10 cm, K 10 , based on measurements of near-saturated hydraulic conductivity made with tension infiltrometers in 70 soil horizons at 37 different sites in 0016-7061/02/$ -see front matter D 2002 Elsevier Science B.V. All rights reserved. PII: S 0 0 1 6 -7 0 6 1 ( 0 1 ) 0 0 1 5 4 -9 (N.J. Jar vis).
Dependence of effective hydraulic conductivity on rainfall intensity: loamy agricultural soils
Hydrological Processes, 2010
Effective hydraulic conductivity (K e ) can be estimated with statistical models derived from datasets of field measured conductivities. Pedotransfer functions (PTFs) estimate constant K e values, but suffer from large prediction errors because the functions usually do not account for soil structural heterogeneities. Rainfall-runoff data have shown that the effective hydraulic conductivity, defined as final infiltration rate at steady state given ponding, is dependent on rainfall intensity. In this study a statistical approach to establish functions for rainfall intensity-dependent K e values is presented, including some specific functions for Western European loamy agricultural soils. Steady-state rainfall experiments have been conducted with a drip-type rainfall simulator at multiple intensities on small plots, installed on fields covered by four typical crops of the central part of the Belgian loess belt. A mixed linear model has been applied to temperature standardized and ln-transformed values of apparent steady-state infiltration rate and rainfall intensity data for the determination of significant explanatory variables and their parameters. Crop type was a necessary classification effect that accounts for much of the variation that could not be explained by continuous variables of soil and surface properties. However, soil surface bulk density, silt and sand content, tortuosity in surface microtopography, plant and residue cover (RC) were predictors that improved predictions combined with crop effect. Model efficiency (ME) values were between 0Ð81 and 0Ð97 for calibration and between 0Ð75 and 0Ð95 for validation. The application of the functions is limited to sloping, loamy agricultural soils in a Western European climate, during the spring and early summer growing phase, with not fully developed canopy cover and an RC of less than 20%. These limitations bound field conditions that are vulnerable to severe erosion events. A dynamic K e could be applied in infiltration models, changing runoff and erosion response in hillslope models.
Geosciences, 2021
Saturated hydraulic conductivity (Ks) of soil, especially of the upper soil layer, is a basic parameter for modeling water infiltration and solute transport in the soil. In the present study, spatial and temporal variability of Ks in the upper soil layer of a loam soil, which was covered by native vegetation for 20 years and had not undergone any cultivation treatment, is investigated. Saturated hydraulic conductivity of 76 undisturbed soil samples, taken twice a year at the dry (37 soil samples) and rainy periods (39 soil samples), was measured using a constant head method. The study reveals that Ks values exhibit significant spatial variability over the two time periods of measurement and follow a lognormal distribution with a coefficient of variation greater than 70%. On the contrary, there was no statistically significant seasonal variability of Ks between summer (dry period) and winter (rainy period) sampling (p > 0.05), and, therefore, there was no significant temporal vari...
Relating Quantitative Soil Structure Metrics to Saturated Hydraulic Conductivity
Vadose Zone Journal, 2016
Soil structure affects saturated hydraulic conductivity (K s) by creating highly conductive macropores that preferentially transmit soil water. In this study, we explored the relationship between K s and macropores in an Oxyaquic Vertic Argiudoll in northeastern Kansas. Macropores were quantified from an excavation wall using multistripe laser triangulation (MLT) scanning. Soil water contents were measured at four depths within a soil lysimeter installed within 2 m of the MLT-scanned soil profile and adjacent to an Ameriflux tower monitoring precipitation, air temperature, and solar radiation. Selected hydraulic properties of soil horizons within the lysimeter were optimized to water content data using a Markov chain Monte Carlo technique in combination with the mobile-immobile water (MIM) model in HYDRUS-1D. Estimates of K s varied between 4198 cm d −1 in the A horizon and 0.6 cm d −1 in a 2Btss2 horizon with strongly expressed wedge structure. Approximately 87% of the variation in K s was explained by the geometric mean of the widths of pores quantified with the MLT technique and modified by the coefficient of linear extensibility (COLE). The use of the COLE allows the widths of the macropores obtained under dry conditions to be approximated at saturation. Two models that predict K s from either texture or water retention data resulted in K s estimates that were similar to each other but significantly lower than K s values predicted with MIM in horizons where structural pores dominate water flow. This technique shows a great deal of promise in better understanding and predicting the relationship of soil structure to water flow.
Understanding saturated hydraulic conductivity under seasonal changes in climate and land use
Geoderma, 2018
The goal of this study was to understand better the co-play of intrinsic soil properties and extrinsic factors of climate and management in the estimation of saturated hydraulic conductivity (Ksat) in intensively managed landscapes. For this purpose, a physically-based, modeling framework was developed using hydropedotransfer functions (PTFs) and watershed models integrated with Geographic Information System (GIS) modules. The integrated models were then used to develop Ksat maps for the Clear Creek, Iowa watershed and the state of Iowa. Four types of saturated hydraulic conductivity were considered, namely the baseline (Kb), the bare (Kbr), the effective with no-rain (Ke-nr) and the effective (Ke) in order to evaluate how management and seasonality affect Ksat spatiotemporal variability. Kb is dictated by soil texture and bulk density, whereas Kbr, Ke-nr, and Ke are driven by extrinsic factors, which vary on an event to seasonal time scale, such as vegetation cover, land use, management practices, and precipitation. Two seasons were selected to demonstrate Ksat dynamics in the Clear Creek watershed, IA and the state of Iowa; specifically, the months of October and April that corresponded to the before harvesting and before planting conditions, respectively. Statistical analysis of the Clear Creek data showed that intrinsic soil properties incorporated in Kb do not reflect the degree of soil surface disturbance due to tillage and raindrop impact. Additionally, vegetation cover affected the infiltration rate. It was found that the use of Kbinstead of Ke in water balance studies can lead to an overestimation of the amount of water infiltrated in agricultural watersheds by a factor of two. Therefore, we suggest herein that Keis both the most dynamic and representative saturated hydraulic conductivity for intensively managed landscapes because it accounts for the contributions of land cover and management, local hydropedology and climate condition, which all affect the soil porosity and structure and hence, Ksat.
Jurnal Pengelolaan Sumberdaya Alam dan Lingkungan (Journal of Natural Resources and Environmental Management)
Soil hydraulic conductivity is one of the important soil characteristics that determines the amount and proportion of water that will be infiltrated into the soil column and flowing as surface runoff. It is strongly influenced by soil porosity and soil characteristics that affect the soil porosity such as soil texture and structure and soil organic matter content (internally factors) as well as land management and the intensity of plant canopy cover (external factors). This research is aimed to identify the character of soil hydraulics conductivity in different landuse that consist of forest, agricultural land (moor land, cacao plantations, intensive and conservation annual crops), and green open space areas. The results showed that: a) forest conversion into agricultural land led to the decline of soil quality such as decreased levels of soil organic matter, soil porosity and distribution of soil pores so that the conversion of forest land into agricultural land decreases the soil ...
Journal of Applied and Natural Science
hree soil profiles from Regional Research Station of Bidhan Chandra Krishi Viswavidyalaya, Gayeshpur situated in New Alluvial zone of Nadia district, West Bengal were studied to assess the predictability of the hydraulic conductivity of the soil as influenced by different physical and chemical and properties of cultivated and forest land. The various statistical procedures were employed on the measured laboratory based data for comprehensive agree-ment of dependent hydraulic conductivity of soils as a model function of independent soil variables that is likely to be useful for different land cover systems. Soils are neutral in reaction, silty clay to silty clay loam in nature. Forest soil contained greater organic carbon (OC) (5.9 ± 0.16 g kg-1) compared to cultivated soil (4.4 ± 0.34 g kg-1). Jhau plan-tation recorded the highest value (6.8 g kg-1) of OC due to soil texture and cation exchange capacity (CEC). Soil hydraulic conductivity was greater in soil for cabbage and Sagun tre...