ASSESSMENT OF A COMBINATION OF WET SIEVING AND TURBIDIMETRY TO CHARACTERIZE THE STRUCTURAL STABILITY OF MOIST AGGREGATES

1990 ◽  
Vol 70 (1) ◽  
pp. 33-42 ◽  
Author(s):  
T. POJASOK ◽  
B. D. KAY
Keyword(s):  
Organic Matter ◽  
Structural Stability ◽  
Organic Matter Content ◽  
Aggregate Stability ◽  
Clay Content ◽  
Matter Content ◽  
Wet Aggregate Stability ◽  
Large Investment ◽  
Dispersible Clay ◽  
Wet Sieving

A method of measuring the structural stability of moist soils using a combination of turbidimetry and wet sieving has been developed and assessed. Aggregates of 1–2 mm in diameter are shaken end-over-end in test tubes and dispersed clay and stable aggregates greater than 0.25 mm diameter measured. Stabilities determined using this method were compared to stabilities determined using a modification of the Yoder wet-sieving method on 20 soils of different textures, organic-matter content, and recent cropping history. Wet aggregate stabilities determined by the two methods were correlated although the two measurements exhibited different sensitivities to clay content, organic-matter content and moisture content at the time of sampling. Dispersible clay was found to be a function of total clay content, organic-matter content and water content at the time of sampling. The new method offers the advantage of stability measurements of structural units of much different size using the same energy input and can be readily adapted to the routine analysis of a large number of samples without a large investment in equipment or space. Key words: Wet aggregate stability, dispersible clay, cropping history, soil structure

Comparison of aggregate stability within six soil profiles under conventional tillage using various laboratory tests

Biologia ◽  
2009 ◽  
Vol 64 (3) ◽  
Author(s):  
Radka Kodešová ◽  
Marcela Rohošková ◽  
Anna Žigová
Keyword(s):  
Organic Matter ◽  
Soil Aggregates ◽  
Organic Matter Content ◽  
Aggregate Stability ◽  
Clay Content ◽  
Soil Aggregate ◽  
Matter Content ◽  
The Other ◽  
Structure Stability ◽  
Soil Aggregate Stability

AbstractSoil structure stability was studied in every diagnostic horizons of six soil types (Haplic Chernozem, Greyic Phaeozem, two Haplic Luvisols, Haplic Cambisol, Dystric Cambisol) using different techniques investigating various destruction mechanisms of soil aggregates. Soil aggregate stability, assessed by the index of water stable aggregates (WSA), varied depending on the organic matter content, clay content and pHKCl. The presence of clay and organic matter coatings and fillings, and presence of iron oxides in some soils increased stability of soil aggregates. On the other hand periodical tillage apparently decreased aggregate stability in the Ap horizons. Coefficients of aggregate vulnerability resulting from fast wetting (KV 1) and slow wetting (KV 2) tests showed similar trends of the soil aggregate stability as the WSA index, when studied for soils developed on the similar parent material. There was found close correlation between the WSA index and the KV 1 value, which depended also on the organic matter content, clay content and pHKCl. Less significant correlation was obtained between the WSA index and the KV 2 value, which depended on the organic matter content and clay content. Coefficients of vulnerability resulting from the shaking after pre-wetting test (KV 3) showed considerably different trends in comparison to the other tests due to the different factors affecting aggregate stability against the mechanical destruction. The KV 3 value depended mostly on cation exchange capacity, pHKCl and organic matter content.

scholarly journals Erosion Effect on Soil Physical Properties in Selected Farmlands in Gidan Kwano, Niger State

2018 ◽  
Vol 2 ◽  
pp. 10-22
Author(s):  
Abdulkadir Abdullahi
Keyword(s):  
Organic Matter ◽  
Physical Properties ◽  
Bulk Density ◽  
Organic Matter Content ◽  
Aggregate Stability ◽  
Clay Content ◽  
Infiltration Rate ◽  
Matter Content ◽  
Simple Method ◽  
Cumulative Infiltration

The study was conducted to investigate if erosion is a major problem and to identify the effect of erosion on some physical properties on selected farmlands on four farms in Gidan kwano. It was done by observation, interview, and questionnaire and soil sample analysis. The infiltration rate, bulk density, porosity, organic matter content, particle size and aggregate stability were determined for all the sample location. The erosion fields results were compared with the results of the non-eroded fields. The results showed that farming was done with simple method and mechanized equipment when available and erosion was considered a major problem in all the farms. The results revealed that bulk density values ranged between 1.475gcm-3and 1.606gcm-3, cumulative infiltration rate fluctuated between 29.75cm/hr and 37.48cm/hr, porosity ranged between 36.49% and 44.34%, organic matter content fluctuated between 0.29% and 0.73% and aggregate stability ranged between 58.00% and 67.60% for the erosion field. The results also revealed that bulk density fluctuated between 1.458gcm-3and 1.544gcm-3, cumulative infiltration rate ranged between 32.19 cm/hr and 40.48cm/hr, porosity fluctuated between 41.73% and 44.98%, organic matter content ranged between 0.30% and 1.09% and aggregate stability ranged between 63.97% and 68.93% for the non-eroded field. From the results, it provides evidence that the effects of erosion on the physical properties were increased bulk density, decreased infiltration rate, organic matter content, porosity, aggregate stability and percentage sand, silt and clay content. Statistical analysis proved that the results were significant (p<0.05) except for the bulk density and porosity which could be attributed to the swelling and compaction characteristics of the soils.

EFFECT OF ROOT EXUDATES FROM CORN AND BROMEGRASS ON SOIL STRUCTURAL STABILITY

1990 ◽  
Vol 70 (3) ◽  
pp. 351-362 ◽  
Author(s):  
T. POJASOK ◽  
B. D. KAY
Keyword(s):  
Structural Stability ◽  
Root Exudates ◽  
Soil Structure ◽  
Aggregate Stability ◽  
Clay Content ◽  
Flash Evaporation ◽  
Metal Organic ◽  
Loam Soil ◽  
Wet Aggregate Stability ◽  
Dispersible Clay

The effect of root exudates on structural stability and the hypothesis that the growing roots of corn (Zea mays L.) can destabilize soil structure by chelating Fe and Al involved in mineral-metal-organic matter linkages were investigated. Exudates were removed from 14C-labelled corn and bromegrass (Bromus inermis Leyss.) plants grown in sand using sequential leaching with water and acetone. The exudates were concentrated by flash evaporation and incubated with 1–2 mm aggregates of a calcareous silt loam soil for up to 240 h. Aggregates to which exudates from bromegrass were added had a higher wet aggregate stability (WAS) and lower dispersible clay content (DC) than aggregates to which exudates from corn were added. The greatest increase in stability occurred on addition of the water-extracted exudates (9.6% for WAS, 27.1% for DC). The increase in stability correlated positively with a release into solution of Ca and Mg from the soil solids. Addition of CaCl2 to the aggregates, to give corresponding amounts of Ca and Mg in solution, had similar effects on stability suggesting that the ions released by the exudates were not in a chelated form. The quantity of carbon added in the exudates and the mineralization of this carbon were positively and negatively correlated with stability, respectively. There was little evidence that corn exudates caused a destabilization of structure. Key words: Wet aggregate stability, dispersible clay, corn, bromegrass, flocculation, calcium

scholarly journals Factors Affecting Microbial Formation of Nitrate-Nitrogen in Soil and Their Effects on Fertilizer Nitrogen Use Efficiency

2001 ◽  
Vol 1 ◽  
pp. 122-129 ◽  
Author(s):  
Alan Olness ◽  
Dian Lopez ◽  
David Archer ◽  
Jason Cordes ◽  
Colin Sweeney ◽  
...  
Keyword(s):  
Organic Matter ◽  
Decision Aid ◽  
Pore Space ◽  
Organic Matter Content ◽  
Clay Content ◽  
Matter Content ◽  
N Fertilizer ◽  
Nitrate N ◽  
Soil Clay ◽  
Soil Clay Content

Mineralization of soil organic matter is governed by predictable factors with nitrate-N as the end product. Crop production interrupts the natural balance, accelerates mineralization of N, and elevates levels of nitrate-N in soil. Six factors determine nitrate-N levels in soils: soil clay content, bulk density, organic matter content, pH, temperature, and rainfall. Maximal rates of N mineralization require an optimal level of air-filled pore space. Optimal air-filled pore space depends on soil clay content, soil organic matter content, soil bulk density, and rainfall. Pore space is partitioned into water- and air-filled space. A maximal rate of nitrate formation occurs at a pH of 6.7 and rather modest mineralization rates occur at pH 5.0 and 8.0. Predictions of the soil nitrate-N concentrations with a relative precision of 1 to 4 μg N g–1of soil were obtained with a computerized N fertilizer decision aid. Grain yields obtained using the N fertilizer decision aid were not measurably different from those using adjacent farmer practices, but N fertilizer use was reduced by >10%. Predicting mineralization in this manner allows optimal N applications to be determined for site-specific soil and weather conditions.

scholarly journals A small rainfall simulator for the determination of soil erodibility.

1987 ◽  
Vol 35 (3) ◽  
pp. 407-415 ◽  
Author(s):  
A. Kamphorst
Keyword(s):  
Organic Matter ◽  
Soil Conservation ◽  
Standard Procedure ◽  
Organic Matter Content ◽  
Clay Content ◽  
Matter Content ◽  
Soil Erodibility ◽  
Rainfall Simulator ◽  
Highly Sensitive

A small rainfall simulator is described, which can be used in the field as well as in the laboratory for the determination of infiltration and erosion characterisitcs of soils. It is particularly suitable for soil conservation surveys, as it is light to carry and easy to handle in the field. A description is given of a standard procedure for the determination of topsoil erodibilities in the field and some results are presented. The method appears to be highly sensitive to soil properties influencing soil erodibility, such as clay content, organic matter content and soil pH. (Abstract retrieved from CAB Abstracts by CABI’s permission)

scholarly journals Comparison of wheat and safflower cultivation areas in terms of total carbon and some soil properties under semi-arid climate conditions

2015 ◽  
Vol 7 (1) ◽  
pp. 1007-1024
Author(s):  
B. Turgut
Keyword(s):  
Organic Matter ◽  
Physical Properties ◽  
Organic Matter Content ◽  
Aggregate Stability ◽  
Soil Physical Properties ◽  
Matter Content ◽  
Total Carbon ◽  
Arid Climate ◽  
Soil Layers ◽  
Semi Arid

Abstract. The aim of this study was to compare the soils of the wheat cultivation area (WCA) and the safflower cultivation area (SCA) within semi-arid climate zones in terms of their total carbon, nitrogen, sulphur contents, particle size distribution, aggregate stability, organic matter content, and pH values. This study presents the results from the analyses of 140 soil samples taken at two soil layers (0–10 and 10–20 cm) in the cultivation areas. At the end of the study, it has been established that there were significant differences between the cultivation areas in terms of soil physical properties such as total carbon (TC), total nitrogen (TN), total sulphur (TS) contents and pH, while only the TN content resulted in significantly different between the two soil layers. Moreover significant differences were identified in the cultivation areas in terms of soil physical properties including clay and sand contents, aggregate stability and organic matter content, whereas the only significant difference found among the soil layers was that of their silt content. Since safflower contains higher amounts of biomass than wheat, we found higher amounts of organic matter content and, therefore, higher amounts of TN and TS content in the soils of the SCA. In addition, due to the fact that wheat contains more cellulose – which takes longer to decompose – the TC content of the soil in the WCA were found to be higher than that of the SCA. The results also revealed that the WCA had a higher carbon storage capacity.

Surfactant Effects on Picloram Adsorption by Soils

Weed Science ◽  
1976 ◽  
Vol 24 (6) ◽  
pp. 549-552 ◽  
Author(s):  
J. D. Gaynor ◽  
V. V. Volk
Keyword(s):  
Organic Matter ◽  
Cationic Surfactant ◽  
Anionic Surfactant ◽  
Organic Matter Content ◽  
Clay Content ◽  
Surfactant Solution ◽  
Matter Content ◽  
Adsorption Sites ◽  
Surfactant Solutions ◽  
Extractable Al

The effects of soil organic matter, clay, extractable Al, cation exchange capacity, and pH on the adsorption of picloram (4-amino-3,5,6-trichloropicolinic acid) from aqueous and surfactant solutions were investigated. Linear adsorption isotherms for the soils were obtained with the Freundlich equation. Of the five soil properties investigated, Freundlich K values correlated with extractable Al and clay content. Picloram adsorption from aqueous solutions and from the non-ionic and anionic surfactant solutions was greater on the soils at pH 5 than at pH 7. The anionic surfactant competed with picloram for adsorption sites on the soils at pH 5. Picloram adsorption from solutions containing 0.1 and 1% cationic surfactant was greater than that from aqeuous and anionic and nonionic surfactant solutions. Picloram adsorption from the 10% cationic surfactant solution was similar on soils with pH 5 and 7 and increased with decreased organic matter content.

scholarly journals Relationship of soil properties to fractionation, bioavailability and mobility of lead and zinc in soil

2008 ◽  
Vol 53 (No. 5) ◽  
pp. 225-238 ◽  
Author(s):  
N. Finžgar ◽  
P. Tlustoš ◽  
D. Leštan
Keyword(s):  
Organic Matter ◽  
Regression Analysis ◽  
Soil Organic Matter ◽  
Soil Properties ◽  
Multiple Regression ◽  
Contaminated Soils ◽  
Organic Matter Content ◽  
Clay Content ◽  
Exchange Capacity ◽  
Matter Content

Sequential extractions, metal uptake by <i>Taraxacum officinale</i>, Ruby&rsquo;s physiologically based extraction test (PBET) and toxicity characteristic leaching procedure (TCLP), were used to assess the risk of Pb and Zn in contaminated soils, and to determine relationships among soil characteristics, heavy metals soil fractionation, bioavailability and leachability. Regression analysis using linear and 2nd order polynomial models indicated relationships between Pb and Zn contamination and soil properties, although of small significance (<i>P</i> < 0.05). Statistically highly significant correlations (<i>P</i> < 0.001) were obtained using multiple regression analysis. A correlation between soil cation exchange capacity (CEC) and soil organic matter and clay content was expected. The proportion of Pb in the PBET intestinal phase correlated with total soil Pb and Pb bound to soil oxides and the organic matter fraction. The leachable Pb, extracted with TCLP, correlated with the Pb bound to carbonates and soil organic matter content (<i>R</i><sup>2</sup> = 69%). No highly significant correlations (<i>P</i> < 0.001) for Zn with soil properties or Zn fractionation were obtained using multiple regression.

scholarly journals Response of Fractal Analysis to Soil Quality Succession in Long-Term Compound Soil Improvement of Mu Us Sandy Land, China

2020 ◽  
Vol 2020 ◽  
pp. 1-7
Author(s):  
Haiou Zhang ◽  
Jiancang Xie ◽  
Jichang Han ◽  
Haipeng Nan ◽  
Zhen Guo
Keyword(s):  
Organic Matter ◽  
Sandy Soil ◽  
Sustainable Use ◽  
Organic Matter Content ◽  
Soft Rock ◽  
Clay Content ◽  
Matter Content ◽  
Practical Significance ◽  
Sandy Land ◽  
Mu Us Sandy Land

The degraded aeolian sandy soil in China’s Mu Us Sandy Land requires amendment before it can be suitable for maize or other agricultural production. The addition of material from the local “soft” bedrock can create a new compound soil whose particle composition and structural stability are key issues for sustainable soil development in the region. We used field data from 2010 to 2018 to study the variations in fractal characteristics of compound soil particles at soft rock to sand volume ratios of 1 : 1, 1 : 2, and 1 : 5, along with changes in soil organic matter. Over the study period, all three compound soils showed gradual increases in clay and silt content with corresponding decreasing sand content. The fractal dimension (FD) of particles at ratio 1 : 2 increased by 8.8%, higher than those at 1 : 1 (8.6%) and 1 : 5 (7.7%). The organic matter content (OMC) of particles at ratio 1 : 2 reached a maximum (6.24 ± 0.30 g/kg), an increase of 12 times over the original value. The FD and OMC of particles at ratios 1 : 1 and 1 : 5 were less stable but showed overall increase. The 1 : 2 ratio compound soil was most suitable for maize growth as its clear increase in silt and clay content most improved the texture and OMC of the original sandy soil. Such research has important theoretical and practical significance for understanding the evolutionary mechanism and sustainable use of the compound soil in agriculture within the Mu Us Sandy Land.

Sign in / Sign up

Export Citation Format

Share Document