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.

Morphological and physicochemical properties of various tropical soils from east-central Puerto Rico

1969 ◽  
Vol 36 (2) ◽  
pp. 167-178
Author(s):  
M. A. Lugo López ◽  
M. B. Martínez ◽  
A. R. Riera
Keyword(s):  
Organic Matter ◽  
Puerto Rico ◽  
Laboratory Data ◽  
High Capacity ◽  
Total Porosity ◽  
Tropical Soils ◽  
Drainage Water ◽  
Low Fertility ◽  
Undisturbed Soil ◽  
East Central

This report presents the results of a preliminary soil reconnaissance in east-central Puerto Rico. It contains soil-profile observations made on several deep pits dug for the purpose. It also includes the results of various infiltration tests conducted in the major soil types of the area. The laboratory data reported include organic matter, pH, nitrogen, and total exchange capacity, and also the following measurements conducted on undisturbed soil cores dug with a Kelley (Utah) soil sampling machine: Permeability, quick drainage, water retained at pF 1.78, maximum saturation, and bulk density. Additional data are presented on water retained at pF 2.7 and pF 4.2, available water, total porosity, and air porosity. The soils of east-central Puerto Rico are rather deep, medium- or heavy-textured, acid, and of medium to low fertility. They are not generally well supplied with organic matter and nitrogen. In many cases they have compact, tight subsoil layers near the surface which considerably reduce the permeability of the profile and induce poor drainage. Laboratory soil-moisture studies confirmed field observations indicating that the majority of the soils of this region have a moderately high capacity to store water available for crop growth.

scholarly journals Available Cd content of salt-affected and normal soils of Halastra-Kalohori area

2013 ◽  
Vol 9 (3) ◽  
pp. 195-200
Keyword(s):  
Exchange Capacity ◽  
Soil Samples ◽  
Water Soluble ◽  
Sodium Absorption ◽  
Rice Soil ◽  
P Fertilization ◽  
Mean Values ◽  
Olsen P ◽  
Sodium Absorption Ratio ◽  
Almost All

A survey was conducted in order to evaluate the levels of available (DTPA extractable) Cd in salt affected and normal soils of Halastra−Kalohori area, located in N. Greece. In this area, phosphogypsum (PG) (a byproduct of P fertilizer industry, occasionally enriched with Cd) has been used as amendment for the salt affected soils, for at least 20 years until 2000. The area is about 6300 ha, and 4500 ha were cultivated with rice. Soil samples were collected from 632 points and four depths (0−25, 25−50, 50−75, 75−100 cm), during 2003 and 2004. All soil samples were analyzed for particle size distribution, pH in the paste, electrical conductivity of the saturation extract (ECe), water soluble Na, Ca and Mg, cation exchange capacity (CEC) and exchangeable Na. The sodium absorption ratio (SAR) and exchangeable sodium percentage (ESP) were calculated. The 632 soils were characterized as salt affected (saline, saline−sodic, sodic) or normal, using the values of EC, SAR and ESP, and pH. In addition, the soil samples collected from the 0−25 and 25−50 cm depths were analyzed for DTPA extractable Cd and Olsen P. All soils were alkaline in reaction. In most of the cases, concentrations of DTPA extractable Cd in the 0−25 cm depth were higher than in the 25−50 cm depth and the mean values differed significantly (p < 0.001). For both depths, concentrations of DTPA extractable Cd were higher for salt affected than normal soils and the mean values within each depth differed significantly (p < 0.001). This could be attributed to the use of PG as soil amendment. In addition, a significant and positive relationship was obtained for DTPA extractable Cd and ECe (r = 0.31, p < 0.001). However, DTPA extractable Cd ranged at levels similar or lower to those reported in the literature for cultivated soils with high P fertilization, in almost all cases. This is something to be expected since 80 % of all soils were sufficient or over−fertilized with P (Olsen P > 15 mg kg−1). A significant and positive relationship, obtained for DTPA extractable Cd and Olsen P (r = 0.47, p < 0.001), supported the conclusion that the source of DTPA extractable Cd could also be traced to the long−term P fertilization. Concentrations of DTPA extractable Cd were significantly (p < 0.001) correlated with certain soil properties that affect Cd availability to plants, such as pH (r = −0.26), clay content (r = 0.22) and CEC (r = 0.26).

scholarly journals Assessment of Soil St ructural Stability Under Different Land Uses Using Some Predictive Indices in Abakaliki, Southeastern Nigeria

2015 ◽  
Vol 3 (1) ◽  
pp. 14-19
Author(s):  
J Nwite
Keyword(s):  
Hydraulic Conductivity ◽  
Structural Stability ◽  
Aggregate Stability ◽  
Total Porosity ◽  
Soil Samples ◽  
Fallow Land ◽  
Land Uses ◽  
Mean Weight Diameter ◽  
Core Soil ◽  
Dispersion Ratio

This study was carried out in order to assess soil structural stability under different land uses using predictive indices. Different land uses of forest land, cattle paddock, fallow land and continuously cultivated farmland were carefully identified within Abakaliki agroecology. Auger and core soil samples were collected at five sampling points using free survey technique in each land use. Core soil samples were used to determine predictive indices of bulk density, total porosity and hydraulic conductivity. Auger soil samples were bulked and used for determination of mean weight diameter (MWD), aggregate stability, dispersion ratio and particle size distribution. Data obtained were subjected to coefficient of variation (CV) analysis and standard deviation. Results showed that sand and clay fractions had little variation (%CV<7-8) but silt fraction varied moderately (%CV >28). Furthermore, bulk density, mean weight diameter, aggregate stability and hydraulic conductivity were highly varied (%CV >112-245), total porosity had moderate variation (%CV >30) and dispersion ratio, high variation (%CV >80), respectively. The different land uses are generally rated according to their performance in their structural stability using the predictive indices as forestland>cattle paddock>fallow land>farmland. It is recommended that the practice of forestry, grazing, fallowing and other management practices which encourage formation and stabilization of soil structural stability be adopted for sustenance of higher soil productivity.

scholarly journals Assessing Dispersivity and Expansivity of Clay Soils in the South-East of Yazd with Aim of Investigating Correlation between Them

2019 ◽  
Author(s):  
Nasrin Zare-Junaghani ◽  
Hamid Mehrnahad ◽  
Mehdi Torabi-Kaveh
Keyword(s):  
Construction Projects ◽  
Direct Method ◽  
Soil Samples ◽  
Sodium Absorption ◽  
Swelling Potential ◽  
Indirect Methods ◽  
Swell Index ◽  
Swelling Soils ◽  
Sodium Absorption Ratio ◽  
Problematic Soils

Having knowledge about physical, chemical and mechanical properties of problematic soils is necessary when they are applied in construction projects as borrow materials or foundation, because these soils have potential to create large financial losses. This research deals with characterizing dispersive and swelling soils as problematic soils in southeast of Yazd (center of Iran) with aim of establishing a relationship between dispersivity and expansivity indices. In this regard, after performing a series of physical and chemical tests, the characteristics of the soil samples were determined, and their dispersivity degrees were specified by conducting chemical, pinhole and double hydrometer tests. Also, swelling rates of the soils were estimated using direct method (modified free swell index, MFSI) and indirect methods (different criteria developed for swelling assessment). The results showed that chemical parameters overestimate dispersivity of the soil samples (dispersive to semi-dispersive) in compared to pinhole and double hydrometer tests (slightly non-dispersive to moderately dispersive). Different expansivity degrees were defined using the direct and the indirect methods (ignorable to very high) for the soil samples. Among the empirical criteria used to evaluate the swelling potential, the AASHTO's criterion has the closest results to the MFSI in the both boreholes. Also, it revealed that as depth increases, the degree of soil dispersivity and expansivity decrease in response to the reduction of fine grain content in the samples. Finally, the correlations between dispersivity and expansivity indices, showed that sodium absorption ratio (SAR) can be used as a reasonable index to estimate soil swelling potential.

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 Thixotropic Hardening of Fao Clay

2019 ◽  
Vol 25 (5) ◽  
pp. 68-78
Author(s):  
Ahmed Shakir Kamil ◽  
Ala Nasir Aljorany
Keyword(s):  
Shear Strength ◽  
Soil Structure ◽  
Thick Layer ◽  
Soil Samples ◽  
Silty Clay ◽  
Driven Piles ◽  
Undisturbed Soil ◽  
Clayey Silt ◽  
Natural Water Content ◽  
Intact Soil

Fao region is characterized by weak soft silty clay to clayey silt thick layer which extends to a depth of about 20 m. The construction of some structures on such soils may needs piles. During the installation of driven piles, the soil geotechnical properties are exposed to significant changes result due to shearing under large shear strains. These changes significantly decrease the shear strength of the virgin soil due to the destruction of soil structure caused by remolding. The degradation of shear strength is usually followed by strength regaining which is called “Thixotropy”. In this study, the thixotropic effect on Fao clay was investigated. Many disturbed and undisturbed soil samples were brought from Fao region. Some of the soil samples were thoroughly remolded in the laboratory in its natural water content and molded as direct shear specimens. More than 180 specimens were prepared and tested over 36 weeks in order to accurately assess the percentage of strength regaining with time passing. The results show that soil remolding causes about a 45 % reduction in shear strength in comparing with the shear strength of the intact soil. This reduced percent in shear strength was almost fully regained after 25 weeks due to thixotropic effect.  

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 Assessment of Soil Physical Characteristics of Luvisols Under Monoculture of Vines

2016 ◽  
Vol 19 (1) ◽  
pp. 21-27
Author(s):  
Vladimír Šimanský ◽  
Marek Kolenčík
Keyword(s):  
Soil Profile ◽  
Soil Structure ◽  
Aggregate Stability ◽  
Stability Index ◽  
Total Porosity ◽  
Soil Samples ◽  
Soil Profiles ◽  
Average Content ◽  
Average Value ◽  
Soil Physical Characteristics

Abstract The physical properties of Luvisols under vineyards of the Nitra wine-growing area (Slovakia) were evaluated in the paper. Soil samples were taken from two selected localities (Nitra - Dražovce, Vráble). The obtained results showed that in the soil profile of Dražovce, the average contents of non-capillary pores, capillary pores and semi-capillary pores to the total porosity were equal to 26.1, 64.4 and 9.4%, respectively, and in the soil profile of Vráble - 22.3, 75.6 and 2.1%, respectively. In the Dražovce locality, the average content of aggregate stability index (Sw) decreased in the following order: abandoned vineyard > grassy strip between the vineyard rows > intensively cultivated rows of vineyard. In contrast, in the Vráble locality, higher average contents of Sw were determined in intensively cultivated rows of vineyard in comparison to grassy strip between the vineyard rows. The lowest average value of vulnerability coefficient (Kv) was observed in abandoned vineyard (Dražovce locality) and in both localities in grassy strip between the vineyard rows. Intensive cultivation of the vineyard rows resulted in higher vulnerability of soil structure. The values of maximum capillary capacity were almost the same in both soil profiles of Luvisols. A higher content of soil moisture was observed in the soil profile in the Vráble locality (33.6±2.50) in comparison to the Dražovce locality (30.6±5.44). Higher content of storage moisture was determined in the Vráble locality (2,684 l m-2) in comparison to the Dražovce locality (2,450 l m-2).

Characterization of soils of Ghataprabha Left Bank Canal commandarea of north Karnataka for salinity and sodicity

2016 ◽  
Vol 51 (1) ◽  
Author(s):  
Mallikarjuna Lingappa ◽  
V. B. Kuligod
Keyword(s):  
Electrical Conductivity ◽  
Surface Soil ◽  
Soil Samples ◽  
Water Soluble ◽  
Sodium Absorption ◽  
Command Area ◽  
Left Bank ◽  
Sodium Absorption Ratio ◽  
Salt Affected Soils ◽  
Canal Command Area

A study was conducted to characterize soil salinity and sodicity of Ghataprabha Left Bank Canal command area of Mudhol taluk (Bagalkot District). Bulk Electrical conductivity of salt affected soils was determined by using electromagnetic induction (EM 38). The pHs of surface and sub-surface soil layers ranged from 7.4 to 8.7 and 7.7 to 8.6, respectively. Electrical conductivity of saturated extract of surface and sub-surface soils ranged from 4.2 to 59.9 dSm-1 and 4.2 to 57.0 dSm-1. Majority of soil samples were found to be saline as sodium absorption ratio (SAR) ranged between 0.3 to 10.8 and 0.5 to 10.9 for surface and sub-surface soil, respectively. Among the analysed surface soil samples, 26 per cent were saline, 18 per cent sodic and 56 per cent were saline-sodic. On the other hand, 26, 20 and 54 per cent of soils were categorized into saline, sodic and saline-sodic, respectively. Among the water soluble cations, Na+ (10.9 to 73.4 cmol (P+) kg-1) pre-dominated in surface and sub-surface horizons (10.9 to 65.2 cmol (P+) kg- 1). Among water soluble anions, Cl- dominated both in surface (2.0 to 60 me L-1) and sub-surface (2.0 to 59.0 me L-1).

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

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