scholarly journals Raindrop Energy Impact on the Distribution Characteristics of Splash Aggregates of Cultivated Dark Loessial Cores

Water ◽  
2019 ◽  
Vol 11 (7) ◽  
pp. 1514 ◽  
Author(s):  
Yu Fu ◽  
Guanglu Li ◽  
Dong Wang ◽  
Tenghui Zheng ◽  
Mingxi Yang
Keyword(s):  
Soil Aggregates ◽  
Energy Levels ◽  
Enrichment Ratio ◽  
Particle Sizes ◽  
Splash Erosion ◽  
Energy Impact ◽  
Parabolic Relationship ◽  
Particle Level ◽  
Function Relationship ◽  
Raindrop Energy

To determine the effect of different rainfall energy levels on the breakdown of soil aggregates, this study analyzed the soil splash erosion amounts and the distribution of particle sizes under six rainfall conditions (rainfall energy: 2.41 × 10−5–22.4 × 10−5 J m−2 s−1 and 1.29 × 10−4 J m−2 s−1) at five splash distances (from 0–10 cm to 40–50 cm). Cores of the size 10 × 20 cm of undisturbed cultivated dark loessial soil were selected in tree replicates as the research subject. The results indicated that splashed aggregates were distributed mainly at splash distances of 0–20 cm, which accounted for 66%–90% of the total splash erosion amount. The splash erosion amount significantly decreased exponentially with increasing splash distance for the same rainfall energy (p < 0.01). The splash erosion amount significantly increased in the power function relationship with increasing rainfall energy at the same splash distance (p < 0.05). A model was obtained to predict the splash erosion amount for rainfall energy and splash distance. The fractal dimension (D) of the aggregates showed a downward opening parabolic relationship with raindrop energy. The maximal value of the rainfall energy was 1.286 × 10−4 J m−2 s−1, which broke the aggregates to the largest degree. Enrichment ratio (ER) values for fragments >2 mm were close to 0. A particle size of 0.25 mm was the critical particle level for splash erosion.

Spectroscopy

2006 ◽  
Author(s):  
Abraham Nitzan
Keyword(s):  
Condensed Phase ◽  
Molecular Spectroscopy ◽  
Fundamental Problem ◽  
Optical Transition ◽  
Energy Levels ◽  
Quantum Statistical Mechanics ◽  
Potential Surfaces ◽  
Molecular Systems ◽  
Matter Interaction ◽  
Particle Level

The interaction of light with matter provides some of the most important tools for studying structure and dynamics on the microscopic scale. Atomic and molecular spectroscopy in the low pressure gas phase probes this interaction essentially on the single particle level and yields information about energy levels, state symmetries, and intramolecular potential surfaces. Understanding environmental effects in spectroscopy is important both as a fundamental problem in quantum statistical mechanics and as a prerequisite to the intelligent use of spectroscopic tools to probe and analyze molecular interactions and processes in condensed phases. Spectroscopic observables can be categorized in several ways. We can follow a temporal profile or a frequency resolved spectrum; we may distinguish between observables that reflect linear or nonlinear response to the probe beam; we can study different energy domains and different timescales and we can look at resonant and nonresonant response. This chapter discusses some concepts, issues, and methodologies that pertain to the effect of a condensed phase environment on these observables. For an in-depth look at these issues the reader may consult many texts that focus on particular spectroscopies. With focus on the optical response of molecular systems, effects of condensed phase environments can be broadly discussed within four categories: 1. Several important effects are equilibrium in nature, for example spectral shifts associated with solvent induced changes in solute energy levels are equilibrium properties of the solvent–solute system. Obviously, such observables may themselves be associated with dynamical phenomena, in the example of solvent shifts it is the dynamics of solvation that affects their dynamical evolution. Another class of equilibrium effects on radiation– matter interaction includes properties derived from symmetry rules. A solvent can affect a change in the equilibrium configuration of a chromophore solute and consequently the associated selection rules for a given optical transition. Some optical phenomena are sensitive to the symmetry of the environment, for example, surface versus bulk geometry. 2. The environment affects the properties of the radiation field; the simplest example is the appearance of the dielectric coefficient ε in the theory of radiation–matter interaction.

scholarly journals Effectiveness of Straw Mulch on Infiltration, Splash Erosion, Runoff and Sediment in Laboratory Conditions

2014 ◽  
Vol 22 (1) ◽  
pp. 51-60 ◽  
Author(s):  
Leila Gholami ◽  
Kazimierz Banasik ◽  
Seyed Hamidreza Sadeghi ◽  
Abdulvahed Khaledi Darvishan ◽  
Leszek Hejduk
Keyword(s):  
Soil Loss ◽  
Sandy Loam ◽  
Soil Aggregates ◽  
Sediment Concentration ◽  
Runoff Coefficient ◽  
Splash Erosion ◽  
Straw Mulch ◽  
Conservation Treatment ◽  
Loam Soil ◽  
The Impact

Abstract Mulches have extraordinary potential in reducing surface runoff, increasing infiltration of water into the soil and decreasing soil erosion. The straw mulches as a biological material, has the ability to be a significant physical barrier against the impact of raindrops and reduce the detachment of soil aggregates. The present study is an attempt to determine the efficiency of straw mulch as conservation treatment in changes in the splash erosion, time-to-runoff, runoff coefficient, infiltration coefficient, time-to-drainage, drainage coefficient, sediment concentration and soil loss. The laboratory experiments have been conducted for sandy-loam soil taken from deforested area, about 15 km of Warsaw west, Poland under lab conditions with simulated rainfall intensities of 60 and 120 mmh–1, in 4 soil moistures of 12, 25, 33 and 40% and the slope of 9%. Compared with bare treatments, results of straw mulch application showed the significant conservation effects on splash erosion, runoff coefficient, sediment concentration and soil loss and significant enhancement effects on infiltration and drainage. The results of Spearman-Rho correlation showed the significant (p < 0.05) correlation with r = –0.873, 0.873, 0.878 and 0.764 between rainfall intensity and drainage coefficient, downstream splash, sediment concentration and soil loss and with r = –0.976, 0.927 and –0.927 between initial soil moisture content and time-to-runoff, runoff coefficient and infiltration coefficient, respectively.

scholarly journals Research on Anti-Scourability of Slope Eroded Soil

2021 ◽  
Author(s):  
Liu Xin Chun ◽  
Kang Yongde ◽  
Chen Hong Na ◽  
Lu Hui
Keyword(s):  
Correlation Coefficient ◽  
Loess Plateau ◽  
Water Conservation ◽  
Soil Aggregates ◽  
P Value ◽  
The Loess Plateau ◽  
Exponential Relationship ◽  
R Value ◽  
Function Relationship ◽  
D Value

Purpose - Soil aggregates are of great significance to soil and water conservation and ecological environment construction in arid area of northwest district．Methods - Exploring the effects of different vegetation includes types and land use methods on the stability of soil aggregates in the Loess Plateau, and provide reference for the rational use and management of land, also the improvement of soil structure in the region. Select 9 types of samples of 0-30 cm of typical soil plots as the research objects, compare and analyze the particle size index, stability differences and anti-erodibility of soil aggregates under various vegetation cover. Results - The results show that P value, MWD value, GMD value, D value, and AI value of the 0-10cm surface soil all show the maximum value. As the depth increases, the size distribution of the above index values of each soil sample in the 10-20cm and 20-30cm layers is different; P value in the 0-30cm depth layer is linearly positively correlated with the AI value and MWD value, and linearly negatively correlated with the D value. The correlation coefficient R between each variable is in the range of 0.78-0.97, and the D value reflects the Loess Plateau area stability and erosion resistance of soil aggregates better. GMD and MWD value show an exponential relationship, the correlation coefficient R value of 10-20cm height layer is 0.46; AI and MWD value in 0-10cm, 20-30cm height layer have a power function relationship, 10-20cm height layer has a polynomial function, the correlation coefficient R value is 0.97. The scour coefficient of different soil samples has a high degree of dispersion, the maximum CV value is 1.92, and the minimum value is 0.49. Conclusions - The results of this study can provide a theoretical basis for the ecological and hydrological benefit evaluation of slope erosion control and vegetation restoration on the Loess Plateau.

Fragmentation of soil aggregates induced by secondary raindrop splash erosion

CATENA ◽  
2020 ◽  
Vol 185 ◽  
pp. 104342
Author(s):  
Yu Fu ◽  
Guanglu Li ◽  
Tenghui Zheng ◽  
Yingsong Zhao ◽  
Mingxi Yang
Keyword(s):  
Soil Aggregates ◽  
Splash Erosion ◽  
Raindrop Splash

Splash Erosion Properties of Compacted Cohesive Soil

2013 ◽  
Vol 405-408 ◽  
pp. 68-73
Author(s):  
Kai Sun ◽  
Ji Ru Zhang
Keyword(s):  
Soil Surface ◽  
Cohesive Soil ◽  
Initial Water Content ◽  
Test Model ◽  
Initial Water ◽  
Splash Erosion ◽  
Rainfall Process ◽  
Raindrop Size ◽  
Function Relationship ◽  
The Individual

The effects on different rainfall characteristics and soil properties of rainfall splash erosion were studied by using indoor simulated rainfall device and compacted cohesive soil test model, and then the function relation between them was summarized. The results show that, in the single rainfall process, raindrop size and rainfall splash erosion amount have power function relationship, bigger raindrop diameter, greater splash erosion amount. Soil initial water content and slope show parabola relationship with rainfall splash erosion amount. In the individual rainfall process, there is the same effect law as the single rainfall process. In addition, splash erosion law is consistent whether the soil surface crust or not, but when there is no crust, rainfall splash amount is more than that when there is crust, which illustrates crust can reduce rainfall splash erosion in some extent.

Quantifying contributions of slaking and mechanical breakdown of soil aggregates to splash erosion for different soils from the Loess plateau of China

2018 ◽  
Vol 178 ◽  
pp. 150-158 ◽  
Author(s):  
Hai Xiao ◽  
Gang Liu ◽  
Qiong Zhang ◽  
Zheng Fenli ◽  
Xunchang Zhang ◽  
...  
Keyword(s):  
Loess Plateau ◽  
Soil Aggregates ◽  
The Loess Plateau ◽  
Splash Erosion ◽  
Mechanical Breakdown ◽  
Different Soils

scholarly journals Stability-energy relationships and their application to aggregation studies

1992 ◽  
Vol 72 (4) ◽  
pp. 453-466 ◽  
Author(s):  
L.G. Fuller ◽  
Tee Boon Goh
Keyword(s):  
Soil Aggregates ◽  
Energy Levels ◽  
Aggregate Stability ◽  
Aggregate Size ◽  
Order Rate Constant ◽  
Ultrasonic Dispersion ◽  
First Order ◽  
Energy Relationships ◽  
Stability Energy ◽  
Gray Luvisol

The objective of this study was to develop a method to describe aggregate stability-energy relationships using ultrasonic dispersion and to examine the role played by carbohydrate in soil aggregation. Aggregate size fractions (ASF) from three soils were sonified, and dispersed clay and solubilized carbohydrate measured at energy levels ranging from 0 to 1000 kJ L−1. Study soils included an Orthic Black, Orthic Dark Gray, and Orthic Gray Luvisol, representing the change from a prairie ecosystem to an aspen-forest ecosystem. Ultrasonic dispersion of aggregated clay resulted in characteristic "stability curves" for each ASF which obeyed a first-order decay curve and provided two parameters describing the release of clay from soil aggregates with increasing levels of applied energy: the "stability constant" k and the E1/2 value, which are analogous to a first-order rate constant and half-life, respectively. E1/2 values ranged from 51 to 502 kJ L−1.These values were smallest for the Ae horizon of the Orthic Gray Luvisol and greatest for the macroaggregates of the Ahe horizon of the Orthic Dark Gray. Carbohydrates solubilized upon aggregate destruction generally constituted a minor proportion (10%) of the total ASF carbohydrate, indicating that most of the carbohydrate was strongly adsorbed to surfaces. The development of a stability-energy relationship for aggregates provides a means to study the role of binding agents, such as carbohydrate, in the aggregation process. Key words: Aggregates, ultrasonic dispersion, clay, carbohydrate

scholarly journals Splash erosion in maize crops under conservation management in combination with shallow strip-tillage before sowing

2017 ◽  
Vol 12 (No. 2) ◽  
pp. 106-116 ◽  
Author(s):  
V. Brant ◽  
M. Kroulík ◽  
J. Pivec ◽  
P. Zábranský ◽  
J. Hakl ◽  
...  
Keyword(s):  
Soil Aggregates ◽  
Soil Surface ◽  
Vegetation Period ◽  
Control Treatment ◽  
Plant Residues ◽  
Coverage Ratio ◽  
Splash Erosion ◽  
Plant Coverage ◽  
Strip Tillage ◽  
The Stability

Soil under maize cropping is among the most endangered by erosion. The effect of conservation tillage management on values of splash erosion when using shallow strip tillage before sowing maize was evaluated in the Central Bohemian region (Czech Republic) during the period 2010–2012. The following types of tillage management using conventional technology and shallow tillage were evaluated: ploughed plots with mulch formed by weed biomass (PL<sub>W</sub>), ploughed plots with mulch from perennial ryegrass plants (PL<sub>PR</sub>), ploughed plots without mulch (PL) and shallow tillage (ST) where the mulch was formed by cereals straw. Furthermore, values of the splash erosion, plants and plant residues coverage ratio of soil by image analysis and the stability of soil aggregates were monitored during the whole experiment. The average value of splash erosion (MSR) was higher by 18.7% in the variant of PL<sub>W</sub>, lower by 35.9% in PL<sub>PR</sub>, and lower by 39.5% in ST, than in the control treatment PL (MSR value for PL = 100%) for the whole evaluated period (2010–2012). The average values of the soil surface plant coverage ratio in the plots with mulch ranged from 1.5 to 43.0% at the beginning of the vegetation period, and from 4.9 to 85.5% in the second half of the vegetation period. A positive correlation was observed between the average values of the stability of soil aggregates and the plant coverage ratio of the soil surface in 2010 and 2011.

scholarly journals Splash Erosion on Terraces, Does It Make a Difference If the Terracing Is Done before or after a Fire?

Hydrology ◽  
2021 ◽  
Vol 8 (4) ◽  
pp. 180
Author(s):  
María Fernández-Raga ◽  
Martinho A. S. Martins ◽  
Elena Marcos Porras ◽  
Roberto Fraile ◽  
Jan Jacob Keizer
Keyword(s):  
Meteorological Data ◽  
Soil Aggregates ◽  
Type Model ◽  
Subsurface Hydrology ◽  
Splash Erosion ◽  
Erosion Rates ◽  
Erosion Processes ◽  
High Degree ◽  
The Impact ◽  
Fire Conditions

Terraces are a common Mediterranean feature influencing soils, slopes and subsurface hydrology; however, little is known about their impact on erosion processes, especially in humid regions. The purpose of this study was to assess how terracing after a fire affected erosion processes such as splash erosion. For 8 months, the study monitored splash erosion in three terraced plots, one plot under pre-fire conditions and the other two under post-fire conditions. Assessment of the impact of the terracing treatment in such plots was carried out by the installation of two different splash erosion quantitative systems: cups and funnels. An analysis of the splash data obtained in 17 rainfall events and meteorological data collected during each one of those periods was then performed. A significant positive correlation between the amount of rainfall and the splash erosion was observed. The two splash sampling systems show a high degree of concordance; however, the funnel-type model seems to be the most appropriate when it comes to preventing loss of splashed soil samples. The post-fire treatment with terracing leads to a smaller stability of surface soil aggregates, causing higher splash erosion rates. Sampling using the funnel system collects three times the amount of splashed soil than that collected by the cup system, although both systems correlate appropriately with the meteorological parameters.

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