scholarly journals Relationship between raindrops and ultrasonic energy on the disruption of a Haplic Cambisol

2009 ◽  
Vol 33 (3) ◽  
pp. 814-823 ◽  
Author(s):  
Bruno Teixeira Ribeiro ◽  
José Maria de Lima ◽  
Carlos Rogério de Mello ◽  
Marcos Aurélio Carolino de Sá ◽  
Geraldo César de Oliveira
Keyword(s):  
Aggregate Stability ◽  
Dispersion Curves ◽  
Soil Samples ◽  
Ultrasonic Energy ◽  
Undisturbed Soil ◽  
Different Levels ◽  
Raindrop Impact

The aim of this work was to compare aggregate disruption of undisturbed soil samples by ultrasonic energy to aggregate disruption caused by the energy of simulated raindrops, to provide equations that can describe this relationship, and to evaluate whether aggregate stability, expressed by sonication method, may be used to estimate the effect that raindrops have on undisturbed soil samples. Undisturbed soil samples from A, Bi and C horizons of a Cambisol were submitted to different levels of ultrasonic energy and simulated raindrops. Sieved samples (aggregates) were also submitted to different levels of ultrasonic energy so that both disturbed and undisturbed conditions of samples could be compared. The results showed that the method using ultrasonic energy on undisturbed soil samples can simulate the amount of aggregate disruption of soil due to raindrop impact. Dispersion curves of disturbed samples may not be used to estimate the effect of raindrops on undisturbed soil samples.

scholarly journals Effect of reclamation on the structure of silty-clay soils irrigated with saline-sodic waters

2015 ◽  
Vol 29 (1) ◽  
pp. 23-30 ◽  
Author(s):  
Giovanna Cucci ◽  
Giovanni Lacolla ◽  
Marcello Pagliai ◽  
Nadia Vignozzi
Keyword(s):  
Aggregate Stability ◽  
Total Porosity ◽  
Calcium Sulphate ◽  
Drainage Water ◽  
Soil Samples ◽  
Sodium Absorption ◽  
Silty Clay ◽  
Undisturbed Soil ◽  
Thin Sections ◽  
Sodium Absorption Ratio

Abstract The objective of the work was to evaluate, by using the micromorphometric method, the effects of reclamation on porosity of two different clay loam soils irrigated with saline-sodic waters. Soil samples of the Ap horizon were put in cylindrical containers and irrigated with 9 types of saline-sodic waters (3 levels of salinity combined with 3 levels of sodicity). After a 4-year period, correction treatments were initiated by addition of calcium sulphate and leaching until electrical conductivity and sodium absorption ratio values of the drainage water matched 3 dS m-1 and 9, respectively. After 2 years of correction treatments, undisturbed soil samples were taken from the surface layer and soil thin sections for porosity measurements. Both soils did not show critical macroporosity values (> 10%, below this threshold a soil is classified as compact). Nevertheless, the soils exhibited a different behaviour: total porosity of the Pachic Haploxeroll soil was not affected by difference in water salinity and alkalinity; on the contrary, the Udertic Ustochrept soil showed a lower porosity associated with higher salt concentration in the irrigation waters. This may be due to the different iron and aluminium sesquioxides content and, as a consequence, a different effect on soil aggregate stability.

scholarly journals Soil organic carbon fractions and aggregation of a tropical Alfisol as affected by plant residues

2020 ◽  
pp. 92-101
Keyword(s):  
Organic Carbon ◽  
Leucaena Leucocephala ◽  
Block Design ◽  
Aggregate Stability ◽  
Soil Samples ◽  
Plant Residues ◽  
Panicum Maximum ◽  
Undisturbed Soil ◽  
Carbon Management

Incorporation of plant residues into soil plays vital role in enhancing quality of fragile tropical soils. This study evaluated short-term effect of plant residues of different quality on organic carbon (OC) fractions, carbon management indices and stability of a sandy loam soil with low (< 2%) initial OC content. The residues are Banana clippings (BC), Chromolaena odorata (CO), Leucaena leucocephala (LL), Maize Stover (MS), Neem clippings (NC), and Panicum maximum (PM) applied at 0 t ha-1 (control), 10 t ha-1 and 20 t ha-1 . These treatments were arranged in a randomized complete block design and replicated three times. Undisturbed soil samples were collected at 0-20 cm depth for determination of percent water stable aggregates (%WSA), aggregate ratio (AR) and Mean Weight Diameter (MWD). Pre-sieved (2 mm) soil samples from same depth were collected to determine structural index (SI), microaggregate stability, total OC (CT), labile OC (CL) and non-labile OC (CNL). Carbon indices, i.e. lability index (LI), carbon management index (CMI) and carbon pool index (CPI) were computed from the OC fractions to evaluate the best management practice. The OC fractions were significantly (p≤ 0.05) higher with LL applied at 20 t ha-1 (19.29 g kg-1 for CT, 1.20 g kg-1 for CL and 18.09 g kg-1 for CNL) than other treatments. This was followed by PM 10 t ha-1 , with 17.16 g kg-1 for CT and 16.44 g kg-1 for CNL. The LI (1.29) was highest with MS 10 t ha-1 , while CMI (166.6) and CPI (1.85) were highest with LL 10 t ha-1 and 20 t ha-1 respectively. Significant increase in %WSA of > 0.25 mm size over < 0.25 mm was observed with addition of residues which indicates binding of smaller aggregates into large fractions; while AR (11.97) was highest with CO 10 t ha-1 . Aggregate stability showed MWD (2.02 mm) was highest in soils treated with CO followed by PM (MWD = 1.86 mm) both at 20 t ha-1 ; but SI trend was higher with addition of LL and PM. Computed micro-aggregate stability indices were generally similar for all treatments. High positive correlations were obtained between MWD and CL (r = 0.634), LI (r = 0.686) and CMI (r = 0.641) with addition of Leucaena leucocephala. In conclusion, L. leucocephala, followed by P. maximum and C. odorata provided shortterm improvement in physical quality of this soil over other plant residues

scholarly journals Effect of different Slums on Selected Soil Properties in Abakaliki Southeastern Nigeria

2018 ◽  
pp. 62-65
Author(s):  
Njoku C. ◽  
Okoro G.C.
Keyword(s):  
Heavy Metals ◽  
Crop Production ◽  
Chemical Properties ◽  
Aggregate Stability ◽  
Exchange Capacity ◽  
Soil Samples ◽  
Available Phosphorus ◽  
Southeastern Nigeria ◽  
Undisturbed Soil ◽  
Dispersion Ratio

A study was conducted at Abakaliki to determine the effect of slums on soil physicochem- ical properties. Four replicate samples were collected from the four slum locations and control using auger and core for disturbed and undisturbed soil samples, respectively. The soil samples collected were taken to laboratory and analysed for bulk density, total porosi- ty, mean weight diameter, aggregate stability, dispersion ratio, pH, available phosphorus, total nitrogen, organic carbon, C/N ratio, total exchangeable bases, exchangeable acidity, effective cation exchange capacity, base saturation and heavy metals (Cd, Cu, Pb and Sn). The data obtained were analyzed using analysis of variance (ANOVA) based on CRD and difference between treatment means were dictated using F-LSD. Except for dispersion ratio which is non-significant, all the parameters studied showed significant (p < 0.05) changes with respect to the different locations studied. The result showed lower improve- ment in soil physical and chemical properties in slums than control. On the other hand Cd, Cu, Pb, and Sn were higher in slums than control. Similarly, these heavy metals observed were higher than the usual range in soils. Thus, the study suggests that slum soils should not be used for crop production since they are associated with heavy metal pollutions and also lack the essential nutrients required by crop for performance

Deep Learning Associated with Laser-Induced Breakdown Spectroscopy (LIBS) for the Prediction of Lead in Soil

2019 ◽  
Vol 73 (5) ◽  
pp. 565-573 ◽  
Author(s):  
Yun Zhao ◽  
Mahamed Lamine Guindo ◽  
Xing Xu ◽  
Miao Sun ◽  
Jiyu Peng ◽  
...  
Keyword(s):  
Deep Learning ◽  
Confusion Matrix ◽  
Principal Component ◽  
Classification Performance ◽  
Soil Samples ◽  
Laser Induced Breakdown Spectroscopy ◽  
Support Vector ◽  
Breakdown Spectroscopy ◽  
Laser Induced Breakdown ◽  
Different Levels

In this study, a method based on laser-induced breakdown spectroscopy (LIBS) was developed to detect soil contaminated with Pb. Different levels of Pb were added to soil samples in which tobacco was planted over a period of two to four weeks. Principal component analysis and deep learning with a deep belief network (DBN) were implemented to classify the LIBS data. The robustness of the method was verified through a comparison with the results of a support vector machine and partial least squares discriminant analysis. A confusion matrix of the different algorithms shows that the DBN achieved satisfactory classification performance on all samples of contaminated soil. In terms of classification, the proposed method performed better on samples contaminated for four weeks than on those contaminated for two weeks. The results show that LIBS can be used with deep learning for the detection of heavy metals in soil.

scholarly journals Least limiting water range of Udox soil under degraded pastures on different sun-exposed faces

2017 ◽  
Vol 31 (3) ◽  
pp. 393-400 ◽  
Author(s):  
Renato Ribeiro Passos ◽  
Liovando Marciano da Costa ◽  
Igor Rodrigues de Assis ◽  
Danilo Andrade Santos ◽  
Hugo Alberto Ruiz ◽  
...  
Keyword(s):  
Soil Management ◽  
Sun Exposure ◽  
Soil Samples ◽  
The South ◽  
Undisturbed Soil ◽  
North West ◽  
The North ◽  
Pasture Degradation ◽  
Least Limiting Water Range ◽  
Degraded Pastures

AbstractThe efficient use of water is increasingly important and proper soil management, within the specificities of each region of the country, allows achieving greater efficiency. The South and Caparaó regions of Espírito Santo, Brazil are characterized by relief of ‘hill seas’ with differences in the degree of pasture degradation due to sun exposure. The objective of this study was to evaluate the least limiting water range in Udox soil under degraded pastures with two faces of exposure to the sun and three pedoenvironments. In each pedoenvironment, namely Alegre, Celina, and Café, two areas were selected, one with exposure on the North/West face and the other on the South/East face. In each of these areas, undisturbed soil samples were collected at 0-10 cm depth to determine the least limiting water range. The exposed face of the pasture that received the highest solar incidence (North/West) presented the lowest values in least limiting water range. The least limiting water range proved to be a physical quality indicator for Udox soil under degraded pastures.

scholarly journals DEGRADASI LAHAN PADA KEBUN CAMPURAN DAN TEGALAN DI KABUPATEN DHARMASRAYA

Jurnal Solum ◽  
2007 ◽  
Vol 4 (1) ◽  
pp. 5
Author(s):  
Syafrimen Yasin ◽  
Gusnidar Gusnidar ◽  
Dedy Iskandar
Keyword(s):  
Land Use ◽  
Soil Depth ◽  
Soil Surface ◽  
Soil Samples ◽  
Imperata Cylindrica ◽  
Undisturbed Soil ◽  
Fertility Status ◽  
Land Use Types ◽  
Bulk Volume ◽  
Soil Fertility Status

A research conducted in Sungai Rumbai, Dharmasraya Regency and in Soil Laboratory Andalas university was aimed to evaluate soil fertility status on the depth below 0-20 cm from several land use types , especially under Mixed Garden and annual cultivated dryland soil.  Soil samples were taken on Ultisol at 0-8% slope (late-waving soil surface).  Land use types evaluated were forest, annual cultivated dryland, bush land, rangeland covered by Imperata cylindrica and mixed garden.  Composite soil samples for soil chemical analysis were taken on the 0-20 cm soil depth with four replications, and 5 drillings for each replication.  Undisturbed soil samples by using sample ring were used to analyze sol bulk volume.  The data resulted were compared to the criteria and were statistically tested using Analysis of Variance and then were continued by LSD at 5% level.  From the results of analyses could be concluded that land use  for mixed garden had the higher Organic Carbon (OC) content and the lower bulk volume (BV) than those for annual cultivated dryland soil.Key Words: Degradasi Lahan, Kebun Campuran, Tegalan

scholarly journals Alternative method for volumetric core removal in hardsetting soils

2005 ◽  
Vol 62 (5) ◽  
pp. 493-497 ◽  
Author(s):  
Herdjania Veras de Lima ◽  
Álvaro Pires da Silva ◽  
Sílvia Imhoff ◽  
Afrânio Ferreira Neves Junior
Keyword(s):  
Soil Bulk Density ◽  
Field Method ◽  
Laboratory Method ◽  
Soil Samples ◽  
Soil Core ◽  
Hydraulic Pump ◽  
Undisturbed Soil ◽  
Alternative Method ◽  
Moisture Conditions ◽  
Large Soil

Due to the narrow window of ideal moisture conditions required for collecting undisturbed soil samples from hardsetting horizons in the field, this study compared the efficiency of an alternative method of soil core removal in the laboratory with that of the traditional field method by using measurements of soil bulk density data (Db). In a first sampling, cylinders were removed with a soil sampler in the field. In a second sampling, large soil blocks were removed with Kubiena-type zinc (brass) boxes in the field. Volumetric core cylinder samples were removed from these blocks in the laboratory with a manual hydraulic pump. There were no differences between the Db values determined from the laboratory and the field coring method. The laboratory method was considered more efficient than the field method because it allowed reductions in the errors made by operators in the field, and those caused by differences in soil water content. The laboratory method allows sampling in hardsetting horizons throughout the year, and collecting soil core samples under conditions of controlled moisture and applied force.

The effects of cultivation on the composition of organic-matter and structural stability of soils

Soil Research ◽  
1995 ◽  
Vol 33 (6) ◽  
pp. 975 ◽  
Author(s):  
A Golchin ◽  
P Clarke ◽  
JM Oades ◽  
JO Skjemstad
Keyword(s):  
Organic Matter ◽  
Chemical Composition ◽  
Organic Carbon ◽  
Organic Materials ◽  
Aggregate Stability ◽  
Soil Samples ◽  
Modulus Of Rupture ◽  
Dispersible Clay ◽  
Different Soils

Soil samples were obtained from the surface horizons of five untilled sites and adjacent sites under short- and long-term cultivation. The soil samples were fractionated based on density and organic materials were concentrated in various fractions which enabled comparative chemical composition of the organic materials in cultivated and uncultivated sites by solid-state C-13 CP/MAS NMR spectroscopy. Changes in the nature of organic carbon with cultivation were different in different soils and resulted from variations in the chemistry of carbon inputs to the soils and a greater extent of decomposition of organic materials in cultivated soils. Differences in the chemical composition of organic carbon between cultivated and uncultivated soils resided mostly in organic materials occluded within aggregates, whereas the chemistry of organic matter associated with clay particles showed only small changes. The results indicate a faster decomposition of O-alkyl C in the cultivated soils. Wet aggregate stability, mechanically dispersible clay and modulus of rupture tests were used to assess the effects of cultivation on structural stability of soils. In four of five soils, the virgin sites and sites which had been under long-term pasture had a greater aggregate stability than the cultivated sites. Neither total organic matter nor total O-alkyl C content was closely correlated with aggregate stability, suggesting that only a part of soil carbon or carbohydrate is involved in aggregate stability. The fractions of carbon and O-alkyl C present in the form of particulate organic matter occluded within aggregates were better correlated with aggregate stability (r = 0.86** and 0.88**, respectively). Cultivation was not the dominant factor influencing water-dispersible clay across the range of soil types used in this study. The amount of dispersible clay was a function of total clay content and the percentage of clay dispersed was controlled by factors such as clay mineralogy, CaCO3 and organic matter content of soils. The tendency of different soils for hard-setting and crusting, as a result of structural collapse, was reflected in the modulus of rupture (MOR). The cultivated sites had significantly higher MOR than their non-tilled counterparts. The soils studied had different MOR due to differences in their physical and chemical properties.

scholarly journals Profiling Microbial Communities in Manganese Remediation Systems Treating Coal Mine Drainage

2015 ◽  
Vol 81 (6) ◽  
pp. 2189-2198 ◽  
Author(s):  
Dominique L. Chaput ◽  
Colleen M. Hansel ◽  
William D. Burgos ◽  
Cara M. Santelli
Keyword(s):  
Mine Drainage ◽  
Operational Taxonomic Unit ◽  
Soil Samples ◽  
High Manganese ◽  
Content Type ◽  
Amplicon Pyrosequencing ◽  
Abandoned Coal Mines ◽  
A Minor ◽  
Archaeal Communities ◽  
Different Levels

ABSTRACTWater discharging from abandoned coal mines can contain extremely high manganese levels. Removing this metal is an ongoing challenge. Passive Mn(II) removal beds (MRBs) contain microorganisms that oxidize soluble Mn(II) to insoluble Mn(III/IV) minerals, but system performance is unpredictable. Using amplicon pyrosequencing, we profiled the bacterial, fungal, algal, and archaeal communities in four MRBs, performing at different levels, in Pennsylvania to determine whether they differed among MRBs and from surrounding soil and to establish the relative abundance of known Mn(II) oxidizers. Archaea were not detected; PCRs with archaeal primers returned only nontarget bacterial sequences. Fungal taxonomic profiles differed starkly between sites that remove the majority of influent Mn and those that do not, with the former being dominated byAscomycota(mostlyDothideomycetes) and the latter byBasidiomycota(almost entirelyAgaricomycetes). Taxonomic profiles for the other groups did not differ significantly between MRBs, but operational taxonomic unit-based analyses showed significant clustering by MRB with all three groups (P< 0.05). Soil samples clustered separately from MRBs in all groups except fungi, whose soil samples clustered loosely with their respective MRB. Known Mn(II) oxidizers accounted for a minor proportion of bacterial sequences (up to 0.20%) but a greater proportion of fungal sequences (up to 14.78%). MRB communities are more diverse than previously thought, and more organisms may be capable of Mn(II) oxidation than are currently known.

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