Changes in textural and geo-chemical features of alluvia in the western part of the Lublin Upland over the past 1000 years

In the study the authors analysed the diversity of the textural indices and selected geo-chemical features of sediments that accumulated in the bottoms of valleys in the western part of the Lublin Upland over the past 1000 years. Detailed studies were performed for six profiles with known stratigraphy. The sediments studied varied little in terms of textural features, with a general trend for particle diameters to increase as the depth increased. The characteristics of the sediments indicate a significant role of material supply from the slope systems (mainly gullies) to the bottoms of river valleys. The heavy metal content was characterised by greater vertical variation. In most of the profiles, the youngest deposits were characterised by greater levels of Cd, Cu, Pb and Zn, with enrichment indexes at an average of 1.5–2.5. The observed diversity of the features of sediments, particularly the geo-chemical features, should be attributed to the effect of human activity in the area studied

Changes in textural and geo-chemical features of alluvia in the western part of the Lublin Upland over the past 1000 years

In the study the authors analysed the diversity of the textural indices and selected geo-chemical features of sediments that accumulated in the bottoms of valleys in the western part of the Lublin Upland over the past 1000 years. Detailed studies were performed for six profiles with known stratigraphy. The sediments studied varied little in terms of textural features, with a general trend for particle diameters to increase as the depth increased. The characteristics of the sediments indicate a significant role of material supply from the slope systems (mainly gullies) to the bottoms of river valleys. The heavy metal content was characterised by greater vertical variation. In most of the profiles, the youngest deposits were characterised by greater levels of Cd, Cu, Pb and Zn, with enrichment indexes at an average of 1.5–2.5. The observed diversity of the features of sediments, particularly the geo-chemical features, should be attributed to the effect of human activity in the area studied

Sound Wave Energy Resulting from the Impact of Water Drops on the Soil Surface

<div><p>The splashing of water drops on a soil surface is the first step of water erosion. There have been many investigations into splashing–most are based on recording and analysing images taken with high-speed cameras, or measuring the mass of the soil moved by splashing. Here, we present a new aspect of the splash phenomenon’s characterization the measurement of the sound pressure level and the sound energy of the wave that propagates in the air. The measurements were carried out for 10 consecutive water drop impacts on the soil surface. Three soils were tested (<i>Endogleyic Umbrisol</i>, <i>Fluvic Endogleyic Cambisol</i> and <i>Haplic Chernozem</i>) with four initial moisture levels (pressure heads: 0.1 kPa, 1 kPa, 3.16 kPa and 16 kPa). We found that the values of the sound pressure and sound wave energy were dependent on the particle size distribution of the soil, less dependent on the initial pressure head, and practically the same for subsequent water drops (from the first to the tenth drop). The highest sound pressure level (and the greatest variability) was for <i>Endogleyic Umbrisol</i>, which had the highest sand fraction content. The sound pressure for this soil increased from 29 dB to 42 dB with the next incidence of drops falling on the sample The smallest (and the lowest variability) was for <i>Fluvic Endogleyic Cambisol</i> which had the highest clay fraction. For all experiments the sound pressure level ranged from ~27 to ~42 dB and the energy emitted in the form of sound waves was within the range of 0.14 μJ to 5.26 μJ. This was from 0.03 to 1.07% of the energy of the incident drops.</p></div

Determination of the statistical significance of differences (α significance level = 0.05) for the values shown in Fig. 6 formed between the crown widths of the 5^th and after the impact of the 10^th drops at different initial moisture contents for both soils.

<p>The symbol "+" indicates a statistically significant difference, while "-" indicates no statistically significant difference. Comparisons were made on a "peer-to-peer" basis.</p

Effect of Soil Moisture Content on the Splash Phenomenon Reproducibility

<div><p>One of the methods for testing splash (the first phase of water erosion) may be an analysis of photos taken using so-called high-speed cameras. The aim of this study was to determine the reproducibility of measurements using a single drop splash of simulated precipitation. The height from which the drops fell resulted in a splash of 1.5 m. Tests were carried out using two types of soil: Eutric Cambisol (loamy silt) and Orthic Luvisol (sandy loam); three initial pressure heads were applied equal to 16 kPa, 3.1 kPa, and 0.1 kPa. Images for one, five, and 10 drops were recorded at a rate of 2000 frames per second. It was found that (i) the dispersion of soil caused by the striking of the 1st drop was significantly different from the splash impact caused by subsequent drops; (ii) with every drop, the splash phenomenon proceeded more reproducibly, that is, the number of particles of soil and/or water that splashed were increasingly close to each other; (iii) the number of particles that were detached during the splash were strongly correlated with its surface area; and (iv) the higher the water film was on the surface the smaller the width of the crown was.</p></div

Example of the timing signal for <i>Endogleyic Umbrisol</i> and a pressure head of 3.16 kPa after 10 drops.

<p>Characteristics recorded on one of the eight microphones.</p

The dependence of the course of time (5^th, 10^th and 30^th frames) of the splash phenomenon after the 5^th drop falls.

<p>The dependence of the course of time (5^th, 10^th and 30^th frames) of the splash phenomenon after the 5^th drop falls.</p

Crown widths specified in 2.5*10^-3s (5 frame) after the collapse of the 5^th and 10^th drops.

<p>Error bars represent sample standard deviation of 13 replicates. The number of individual bars defines the values of the coefficients of variation. O—represents <i>Ortic Luvisol</i>, E- represents <i>Eutric Cambisol</i>.</p

The statistical significance of differences between the mean numbers of splashed particles for the 1st, 5th and 10th drops for the different initial moisture levels for two soils.

<div><p>For <i>Eutric Cambisol</i> (left-upper part of the table) and separately for <i>Ortic Luvisol</i> (right-bottom part of the table). The significance was determined at the level α = 0.05. The symbol "+" indicates a statistically significant difference, while "-" indicates no statistically significant difference. Comparisons were made on a "peer-to-peer" basis.</p> <p>Note! A diagonal line separates two independent datasets that were not compared to one another.</p></div