Mini Disk Infiltrometer Research Articles

Evaluating soil water matric pressure and sorptivity relationship as affected by some properties of a clay soil

Sorptivity (S) is the fundamental variable controlling the early infiltration process. Besides soil properties, soil initial water content (θi) and (or) matric pressure (hi) are key factors determining extent of S. Assessment of interrelationship among S, hi, and soil properties can provide a considerable insight into understanding the behaviour of dry soils to rainfall or irrigation water. This study was conducted to evaluate relationship between S and some selected soil parametric and morphometric properties within a range of hi. Sixteen undisturbed soil samples (5 cm id, 5 cm length) were taken from the topsoil (0–15 cm) of a paddy soil with clay texture. Sorptivity was measured with a mini-disc infiltrometer on the samples equilibrated at h, ranging from −20 to −1500 kPa. A parameter (η), representing the relationship between S and hi, was introduced. Correlation analysis was conducted between η and selected soil morphometric and parametric properties. Soil structure and clay content appeared the most important soil attributes influencing S–hirelation between −200 and −1500 kPa. The results provided a fundamental understanding on S–hi–soil properties interrelations in a clay soil. The methodology developed in this study can be used to evaluate S–hirelationship across different soils and scales.

DIMENSIONAL ANALYSIS TO ESTIMATE THE UNSATURATED HYDRAULIC CONDUCTIVITY OF A SANDY LOAM SOIL IN THE AGRICULTURAL FIELD

Hydraulic conductivity in unsaturated soil controls water movement and measuring it in agricultural fields is a challenging task requiring time-consuming, costly, and skilled experimentation. This study was conducted to reduce the cost of experimentation through the development of an estimation model. The developed model is based on dimensional analysis to determine the value of hydraulic conductivity of unsaturated soil as it relates to soil moisture content, irrigation water electrical conductivity, and suction rate (pressure head). Data points were acquired from measurements of cumulative infiltration in the field, using a mini disc infiltrometer. The developed model gave a mean discrepancy ratio of 1.10 (the acceptable range is 0.5–2.0) and a mean percentage of relative errors of 9.96%. These values indicate that the dimensional analysis model is reliable for the prediction of sandy loam soil’s unsaturated hydraulic conductivity.

Propriedades físicas da camada superficial do solo em florestas ripária no Brasil central: resistência à infiltração e penetração

ABSTRACT Plant composition, diversity and structure of riparian forests of Central Brazil are well known. However, little is known about soil physical properties under these forests. This knowledge is important as a baseline for biodiversity restoration and ecosystem services that occur in riparian zones. In order to bridge this gap, here we assessed the infiltration capacity and soil penetration resistance in a plinthic soil under gallery forest in Planaltina, Distrito Federal, Brazil. We measured infiltration capacity (Mini-Disk infiltrometer) and soil penetration resistance (Stolf penetrometer) following linear transects. The plinthic soil had high infiltration capacity and low penetration resistance. Our infiltration estimate is in the middle range when compared to other permeability studies in tropical forests. Like their counterparts, high biological activity along with the lack of disturbance are the likely explanations for such high topsoil permeability to water.

Modelling the Hydrological Effects of Woodland Planting on Infiltration and Peak Discharge Using HEC-HMS

Woodland planting is gaining momentum as a potential method of natural flood management (NFM), due to its ability to break up soil and increase infiltration and water storage. In this study, a 2.2 km2 area in Warwickshire, England, planted with woodland every year from 2006 to 2012, was sampled using a Mini Disk infiltrometer (MDI). Infiltration measurements were taken from 10 and 200 cm away from the trees, from November 2019 to August 2021. Two individual hydrological models were built using the US Hydraulic Engineering Center Hydrological Modelling System (HEC-HMS), to model the effects of infiltration change on peak flows from the site throughout the summer and winter. The models were calibrated and validated using empirical data; the Nash and Sutcliffe Efficiency (NSE) was used as an indicator of accuracy. Results from this study show that woodland planting reduced peak flow intensity compared to impermeable land cover by an average of 6%, 2%, and 1% for 6-h, 24-h, and 96-h winter storms, respectively, and 48%, 18%, and 3% for 6-h, 24-h, and 96-h summer storms, respectively. However, grassland simulations show the greatest reduction in peak flows, being 32%, 21%, and 10%, lower than woodland for 6-, 24-, and 96-h winter storms, respectively, and 6%, 3%, and 0.5% lower than woodland for 6-, 24-, and 96-h summer storms, respectively.

Experimental study on infiltration pattern: opportunities for sustainable management in the Northern region of India

Abstract The infiltration process plays a key role in designing groundwater recharge, irrigation, and drainage systems, and contamination evaluation is controlled by numerous factors, among which soil physical properties and land use & land cover (LULC) are the prime factors. A comprehensive understanding of the spatial water infiltration characteristics over the soil which is site-specific and more complex due to non-uniformity could enhance the agriculture water use efficiency and mitigate water-related issues. The present study deals with the measurement of field infiltration characteristics using a mini disc infiltrometer in all 24 blocks of Gaya districts, Bihar, which covers a wide spectrum of soil types. Results showed that the average cumulative infiltration rate (IR) for the study area varies between 0.38 and 2.20 cm/min with an average rate of 1.16 cm/min. The initial IR among all blocks was found to be high but decreased gradually with each successive reading. Moreover, the land use under forest cumulative IR was more than the cumulative IR for urban and grassland. Eight blocks (33.3%) have an IR more than the average infiltration of the area which is good for storing the water in the aquifer and suggested constructing a recharge structure. Further investigation revealed a small IR in the inundated area, because of the maximum soil water table. The ready-to-use map showing the IR for the district is prepared which could be used by any decision-taking during the high or low rainfall, understanding the hydrological process, development of any reference guide for farmers for increasing the agriculture productivity and soil-water management.

Influence of infiltration on soil erosion in green infrastructures

Abstract Rainwater-induced erosion in green geotechnical infrastructures such as a multilayered landfill cover system (MLCS) is a severe concern in the current era. Although vegetation is a proven measure to control erosion in the MLCS, there are other factors such as infiltration rate which influence the control of the phenomenon. Most of the existing studies are limited to understand influence of vegetation on erosion control or infiltration rate alone. In this study, an attempt is made to incorporate infiltration measurements alongside vegetation cover to understand erosion in surface layer of the MLCS. For this purpose, a pilot MLCS was constructed, and erosion of its surface soil was temporally evaluated through soil loss depth of eroded cover surface under the influence of natural as well as simulated rainfall conditions. Alongside erosion, the amount of vegetated cover was evaluated through photographic image analyses and infiltration rate was measured by mini disk infiltrometer. From the observed results, it is understood that soil erosion and infiltration rate depict a contrasting behaviour with growing vegetation. Antecedent moisture contents were observed to show greater influence on such erosion behaviour which was observed during the testing period. Such studies may be helpful to researchers and practicing engineers for understanding performance of various green geotechnical infrastructures and scheduling the maintenance services to increase the longevity of their layered soil systems.

Hydrological Properties of a Clay Loam Soil as Affected by Biochar Application in a Pot Experiment

Improving soil-water relations by amending soil with biochar might play a significant role in increasing water availability for agricultural crops as well as decreasing water loss through drainage or runoff. While the effects of biochar on the hydrological properties on coarse-textured soils are generally positive and well-documented in the literature, studies on biochar effects on fine-textured soils are rather scarce and even contradictory. Therefore, the aim of this paper was to investigate the impact of biochar on the bulk density, water retention curve (together with several water capacitive indicators) and water infiltration rate in a clay loam soil. A pot experiment was carried out under lab conditions in which biochar was mixed with soil at rates of 0 (B0 or control), 2, 4, 6, 8 and 10% dw (B2, B4, B6, B8 and B10, respectively). Water retention of soil–biochar mixtures at different matrix potentials was determined using a pressure plate apparatus. From these measurements, a series of capacitive indicators was derived and the fitting of the van Genuchten model was also performed. Water infiltration into soil–biochar mixtures was measured by means of a mini-disk infiltrometer and the obtained data were analyzed both directly and by fitting the Philip’s model. Biochar significantly affected the considered soil properties. As the biochar rate increased, the bulk density decreased and water retention increased (B6, B8 and B10 > B2, B4 and B0), while the infiltration rate decreased (B0 > B2, B4, B6, B8 and B10). Although the experiment was performed on sieved and repacked soil samples under lab conditions, the results confirmed that biochar has the potential to increase plant-available water, while possibly reducing drainage water in a clay loam soil by lowering the infiltration rate.

Hydraulic Conductivity Measurement for Three Frozen and Unfrozen Soils in the Red River of the North Basin

HighlightsHydraulic conductivity was measured in frozen and unfrozen soil conditions by a minidisk infiltrometer.In the RRB, frozen sandy loam and silty clay soils had the highest and lowest hydraulic conductivity, respectively.Three simple equations were developed for the three soils to predict frozen soil hydraulic conductivity.Freeze-thaw cycles reduced soil hydraulic conductivity.Abstract. Hydraulic conductivity (k) is a key parameter in describing water movement through a soil profile. In the Red River of the North basin (RRB), the hydraulic properties of frozen soils vary with temperature, water content, and other factors. In this study, a minidisk infiltrometer was used to measure the k values of three soils from the RRB: Colvin silty clay loam, Fargo silty clay, and Hecla sandy loam. The k values were measured for frozen and unfrozen soils with five different initial soil water contents: oven dry, permanent wilting point, field capacity, midway between permanent wilting point and field capacity, and saturation. The results showed that the mean k value of a frozen soil increased with an increase in initial soil water contents. Hecla soil had the highest k values and Fargo soil had the lowest k values for frozen soils. Three equations were fitted with the measured k values of Colvin silty clay loam, Fargo silty clay, and Hecla sandy loam soils. The k values were also estimated using the Motovilov model. When evaluating model performance, the fitted regression models agreed more closely with the measured k values (index of agreement, d, values of 0.96, 0.94, and 0.94 for Colvin, Fargo, and Hecla soils, respectively) than Motovilov models. Based on overall considerations of statistical measures, the fitted regression models predicted the k values better than Motovilov models for all three frozen soils. It was also found that the k values decreased with an increase in the number of the freeze and thaw cycles that changed the soil properties. Keywords: Frozen soil, Hydraulic conductivity, Mini disk infiltrometer, Red River Valley.

Water infiltration in the Brazilian tropical savanna: the case of Cerrado típico

The Brazilian savanna, regionally known as Cerrado is an important water source due to its spatial position in the highlands known as Planalto Central of Brazil. Yet, the hydrological functioning of such complex ecosystems and its many variations is poorly understood. In this paper, we characterized the soil surface permeability to water under in one of the most common vegetation types: the Cerrado típico which is a type of savanna. In doing so, we measured infiltration capacity using the Mini-Disk infiltrometer (n = 15) and soil resistance to penetration using the Stolf penetrometer (n = 7) in a Latossolo (oxisol) under Cerrado típico located in Brasília (Planaltina), Distrito Federal, Brazil. Our results indicated a high infiltration capacity under Cerrado típico which is potentially associated with a low penetration resistance. This fact might highlight the importance of the natural undisturbed ecosystems, in this case Cerrado típico, as a land-cover which favors hydrological processes which, in turn, promotes soil-groundwater recharge that are inportant to maintain water bodies and reservoirs in the region.

English

The shallow and erodible soils of low fertility uplands have led to farmers extending their cultivable areas to wetlands for optimal crop production since these systems have the potential for exploitation in the dry season. To ensure its sustainable use, the physicochemical and the hydrological characteristics of the valley bottom should be ascertained. Studies were conducted to assess the suitability of wetlands for crop production by analysing the physicochemical properties of Besease wetland soils. Soil samples were collected from specific sites and profile pits for physical and chemical analysis in the laboratory. Field experiments were also conducted for soil physical properties. Soil textural analysis revealed that the average texture of the Besease inland valley was sandy loam with the distribution of sand, silt and clay as 55.42, 35.04 and 9.50%, respectively. Bulk density and moisture content on the field increased with depth in all profiles. Results of hydraulic conductivity using the mini disk infiltrometer ranged from 2 to 88.3 cm/day. The infiltration rate on the studied wetland ranged from 0.02 to 0.78 cm/min. The pH, OC, TN and CEC of the soil profile distribution for site P11-P14 obtained ranged from 6.9-4.6, 4.69-0.19%, 0.2-0.01%, 9- 2.6 meq/100 g down the horizon respectively. The study unraveled a sustained plant nutrient availability and elongation of water level ponding which will result in increased water storage under rice cultivation in the studied wetland. Key words: Wetlands, physicochemical, crop production, nutrient, water storage.

Hydraulic Properties of a Cultivated Soil in Temperate Continental Climate Determined by Mini Disk Infiltrometer

Hydraulic conductivity at and near saturation (Ks and K(h)) are among the most important characteristics defining water behavior in soil. Characterization of possibilities, advantages and limitations of the Mini Disk infiltrometer (MDI) for Ks and K(h) determination in comparison with Hood infiltrometer (HI) was the main aim of this study. The MDI device was subjected to testing on a cultivated silty clay loam soil under three different tillage treatments; conventional, reduced and no-tillage plot. The results are based on 72 infiltration experiments carried out during four experimental phases within one year. Steady-state and transient data analysis methods were applied. K(h) values were determined for van Genuchten hydraulic parameters taken from different sources (two versions of User’s manual, Rosetta). The results show suitability of MDI to determine K(h) of tested soil; clear differences have been observed between the K(h) values measured on plots with different tillage treatment. However, these values were significantly lower (ANOVA, α = 0.05) than those measured by HI. MDI based data were reflecting seasonal changes in structure and pore-size distribution with quantification of macropore contribution to the total saturated flux. Application of K(h) MDI data for fine-textured and structural soils evaluated before 2010 should be reconsidered.

Assessing Water Infiltration and Soil Water Repellency in Brazilian Atlantic Forest Soils

This study presents the results of the soil hydraulic characterization performed under three land covers, namely pasture, 9-year-old restored forest, and remnant forest, in the Brazilian Atlantic Forest. Two types of infiltration tests were performed, namely tension (Mini-Disk Infiltrometer, MDI) and ponding (Beerkan) tests. MDI and Beerkan tests provided complementary information, highlighting a clear increase of the hydraulic conductivity, especially at the remnant forest plots, when moving from near-saturated to saturated conditions. In addition, measuring the unsaturated soil hydraulic conductivity with different water pressure heads allowed the estimation of the macroscopic capillary length in the field. This approach, in conjunction with Beerkan measurements, allowed the design better estimates of the saturated soil hydraulic conductivity under challenging field conditions, such as soil water repellency (SWR). This research also reports, for the first time, evidence of SWR in the Atlantic Forest, which affected the early stage of the infiltration process with more frequency in the remnant forest.

Determination of the soil water repellency of the Mediterranean climate by the use of the mini disk infiltrometer. Case of the micro basin of Tifiles, Tenes, Algeria.

The soil repellency is one of some soil propriety that can be use to indicate the quality of the soil and give a number of information for the soil conservation and the water management. This study show an example of the determination of this parameter in three sites (forest site, after fire forest site and mixed site) by the use of the mini disk infiltrometer test (MDIT) in the small watershed of wadi Tifiles situated in the North West of Algeria that is characterized by a Mediterranean climate. The result show that the water repellency affect namely the after fire forest site which can be equal to 100% of the measured sample flowed by the mixed soil by 93% and the forest site by 80%.

The effect of 12-year ecological farming on the soil hydraulic properties and repellency index

The objective of this study was to elucidate the influence of long-term ecological farming on selected soil properties by comparing results obtained in the field with continuous conventional farming (CT) and those obtained in the field where the original CT was converted into ecological farming system with no-till practice (NT) twelve years earlier. Soil water retention curves were obtained for 100 cm3 undisturbed soil samples using a pressure plate apparatus. Hydraulic conductivity and the repellency index were assessed directly in the field using a mini disk infiltrometer. The examined soil properties showed that NT mostly had a positive influence on the soil quality. The soil water retention capacity represented by the saturated soil water content of 0.32 and 0.40 cm3 cm−3 and the reciprocal of the air-entry pressure head of 0.0227 and 0.0187 cm for CT and NT, respectively, was higher in the NT field than in the CT field. The soil physical quality, represented by the slope of the soil water retention curve at the inflection point of 0.033 (CT) and 0.047 (NT), was better under NT than CT. The hydraulic conductivity at the pressure head of –2 cm was higher in the NT field (0.97 cm hr.−1) than in the CT field (0.17 cm hr.−1). On the other hand, ecological farming increased water repellency (repellency index of 6.73 and 18.91 for CT and NT, respectively).

Sources of inherent infiltration variability in postwildfire soils

AbstractAn automated disc infiltrometer was developed to improve the measurements of soil hydraulic properties (saturated hydraulic conductivity and sorptivity) of soils affected by wildfire. Guidelines are given for interpreting curves showing cumulative infiltration as a function of time measured by the autodisc. The autodisc was used to measure the variability of these soil hydraulic properties in three different sample sets: (a) a reference soil consisting of a nonrepellent, uniform, fine sand; (b) soils with the same soil textural classification derived from the same bedrock geology but having different initial burn severities; and (c) soils from different bedrock geology but having the same burn severity. The autodisc infiltrometer had greater sampling rates and volume resolution when compared with the visual minidisc infiltrometer from previous studies. There was no statistical difference in the mean values measured using the autodisc and visual minidisc, but the variability of the autodisc measurements was significantly less than the visual minidisc for a given set of samples. The greatest variability of soil hydraulic properties in reference samples with uniform particle size was attributed to different pore geometries (coefficient of variation [COV] = 0.28–0.34). Unburned field samples (same soil type) with heterogeneous particle sizes had greater variability (COV = 0.57–0.78) than the reference samples. However, this basic variability decreased or remained constant in these field samples as burn severity increased. Additional sources of variability (COV = 0.53–1.99) were attributed to multiple layers resulting from ash or sediment deposition. Results indicate that resolving differences in soil hydraulic properties from different sites requires more than the common 10 random samples because of the multiple sources of variability.

Random forest, M5P and regression analysis to estimate the field unsaturated hydraulic conductivity

Hydraulic conductivity of soil reveals its influencing role in the studies related to management of surface and subsurface flow, e.g. irrigation and drainage projects, and solute mass transport models. Direct measurements of hydraulic conductivity have many difficulties due to spatial variation of the property in the field. Pertaining to this problem, in this study, estimation models have been developed using machine learning methods (M5 tree model and random forest model) in an attempt to estimate the accurate values of unsaturated hydraulic conductivity related to basic soil properties (clay, silt and sand content, bulk density and moisture content). Data set was collected from the experimental measurements of cumulative infiltration using mini disc infiltrometer at the study area (Kurukshetra, India). A multivariate nonlinear regression (MNLR) relationship was derived, and the performance of this model was compared with the machine learning-based models. The evaluation of the results, based on statistical criteria (R2, RMSE, MAE), suggested that random forest regression model is superior in accurate estimations of the unsaturated hydraulic conductivity of field data relative to M5 model tree and MNLR.

Impact of Soil Amendments on the Hydraulic Conductivity of Boreal Agricultural Podzols

Hydraulic properties of soil are the basis for understanding the flow and transport through the vadose zone. It has been demonstrated that different soil amendments can alter the soil properties affecting soil hydrology. The aim of this study was to determine the effect of soil amendments on hydraulic conductivity (K) of a loamy sand podzolic soil under both unsaturated (Kunsat) and near-saturated (near Ksat) conditions in an agricultural setting. A field experiment was conducted with two common soil amendments: Dairy manure (DM) in 2016 and 2017 and biochar (BC) once only in 2016. DM and BC were incorporated up to a depth of 0.15–0.20 m at a rate of 30,000 L ha−1 and 20 Mg ha−1, respectively. A randomized complete block experimental design was used and the plots planted with silage corn (Zea mays L.) without irrigation. The treatments were: Control without amendment (0N), inorganic N fertilizer (IN), two types of DM (IN+DM1 and IN+DM2), and two treatments with BC (IN+BC and IN+DM1+BC). Infiltration data were collected using a mini disk infiltrometer under three tension levels in which −0.04 and −0.02 m was ascribed as unsaturated (at the wet end) and −0.001 m as near-saturated condition. Based on the measured infiltration rates, Kunsat and near Ksat hydraulic conductivities were calculated. There were no significant effects of DM and BC on bulk density and near Ksat. Treatments IN+DM1, IN+DM2, and IN+DM1+BC significantly reduced the Kunsat compared to the control. Since these soil amendments can influence soil hydrology such as reduced infiltration and increased surface runoff, carefully monitored application of soil amendments is recommended.

Measuring dynamic changes of soil porosity during compaction

Soil porosity and pore-size distribution changes in response to compaction are important for heat, water, and air flow in soils. In this study, we used the thermo-time domain reflectometry (thermo-TDR) technique to investigate dynamics of in-situ soil porosity and pore-size distribution as affected by number of traffic passes, water content and soil depth. The study was conducted at a field site located near Clayton, NC, USA. A roller was dragged across the length of a 3- by 12-m plot three to five times to repeatedly compact the soil after tillage. Nine thermo-TDR probes, installed at 2.5-, 7.5-, and 12.5-cm depths (representing 0–5, 5–10, and 10–15 cm depth intervals, respectively) at three locations within the plot, were used to determine dynamic changes in soil porosity after each compaction event. Pore-size distribution changes within the top soil layer were determined for a subset of conditions by measuring in-situ infiltration at low tension using a mini disk infiltrometer. Nine core samples were also collected (considered to be a destructive method) near each thermo-TDR probe for measuring total porosity and water content after each compaction. Results showed that the thermo-TDR technique can accurately monitor the change of soil porosity during soil compaction compared to the destructive core method. Variability of replicated soil porosity measurements by the thermo-TDR technique (with a root mean square error (RMSE) of 0.011 m3 m−3 and mean standard error (MSE) of 0.010 m3 m−3) was lower than that of the core method (RMSE = 0.017 m3 m−3, MSE = 0.019 m3 m−3). As expected, total soil porosity decreased with the number of passes; a major portion of compaction (59–89% of the total porosity decrease) occurred during the first pass. The trend of topsoil (0–5 cm) compaction differed from that of subsoil layers (5–10 and 10–15 cm). Changes in porosity were highly sensitive to soil water content. For the sandy-textured soil in this study, soil porosity decreased as water content increased (during compaction period), and the maximum compaction (associated with the lowest porosity) was reached at an initial water content range between 0.08 and 0.10 g g-1. Above this range, the compaction level decreased with increasing water content. In addition, there was a shift in pore-size distribution for the surface layer. More importantly, pore-size distribution continued to change with additional traffic passes even after soil total porosity became stable.

Determination of Spatial and Temporal Variability of Soil Hydraulic Conductivity for Urban Runoff Modelling

Soil hydraulic conductivity has a direct influence on infiltration rate, which is of great importance for modelling and design of surface runoff and stormwater control measures. In this study, three measuring techniques for determination of soil hydraulic conductivity were compared in an urban catchment in Ljubljana, Slovenia. Double ring (DRI) and dual head infiltrometer (DHI) were applied to measure saturated hydraulic conductivity (Ks) and mini disk infiltrometer (MDI) was applied to measure unsaturated hydraulic conductivity (K), which was recalculated in Ks in order to compare the results. Results showed significant differences between investigated techniques, namely DHI showed 6.8 times higher values of Ks in comparison to DRI. On the other hand, Ks values obtained by MDI and DRI exhibited the lowest difference. MDI measurements in 12 locations of the small plot pointed to the spatial variability of K ranging between 73%–89% as well as to temporal variability within a single location of 27%–99%. Additionally, a reduction of K caused by the effect of drought-induced water repellency was observed. Moreover, results indicate that hydrological models could be enhanced using different scenarios by employing a range of K values based on soil conditions.

Estimation of macropore flow characteristics in stony soils of a small mountain catchment

The rapid movement of water in a complex system of preferential pathways in soils is a common natural phenomenon. However, quantification of the properties of this phenomenon is not easy and such results are not often found in the literature. The paper presents results of quantification of the number of macropores, their relative volume and the ratio of water infiltrating through the macropores for five study sites with stony soils located in a mountain catchment of northern Slovakia. These characteristics were calculated from the saturated and unsaturated soil hydraulic conductivities under the assumptions of the Poiseuille’s law. Saturated hydraulic conductivities were estimated by single ring infiltrometer measurements in the field and by falling head method in the laboratory. Unsaturated hydraulic conductivities were estimated by tension infiltration measurements in the field (using a minidisc infiltrometer, Decagon Devices). The largest amount of macropores (defined as the pores with radius larger than 1.5 mm) in the entire soil profile (7–5276 per 1 m2) was found at forest sites overgrown by spruce with high to extremely high stoniness. The number of macropores decreased with depth of the soil profile at all study sites. The contribution of macropore flow to water infiltration varied from approximately 63% to almost 100%. Although macropores can conduct a large proportion of water, their relative volume is small (0.001–0.9%). The relative volume of all macropores (active and non-active) estimated from the soil porosity and the water retention function was in the range 2–23%.