Structural stability of sodic soils in sugarcane production as influenced by gypsum and molasses

2002 ◽  
Vol 42 (3) ◽  
pp. 315 ◽  
Author(s):  
A. Suriadi ◽  
R. S. Murray ◽  
C. D. Grant ◽  
P. N. Nelson
Keyword(s):  
Structural Stability ◽  
Aggregate Stability ◽  
Clay Loam ◽  
Exchangeable Sodium ◽  
Sodic Soils ◽  
Clay Dispersion ◽  
Sugarcane Production ◽  
Mechanical Dispersion ◽  
Wet Aggregate Stability ◽  
Dispersible Clay

The aim of this work was to determine whether molasses, a by-product of sugar manufacture, alone or combined with gypsum, could improve the structural stability of sodic soils used for sugarcane production. A Burdekin sandy clay loam with an exchangeable sodium percentage (ESP) of 7.9, and a Proserpine loamy sand with an ESP of 18.8 were incubated with molasses (0 and 10 t/ha) and gypsum (0 and 10 t/ha) for 12 weeks, during which time they were leached 5 times with water (0.5 pore volumes each time). In the Burdekin soil, molasses and gypsum, either alone or combined, decreased spontaneous clay dispersion from 2.6 to <0.2 g/kg soil. Mechanical dispersion was reduced from 21.2 to <0.2 g/kg soil by gypsum alone, and to 14.9 g/kg soil by molasses alone. Molasses and gypsum both increased wet aggregate stability, with the combined effect being greatest; the proportion of aggregates >250 μm was 31% in the control and 71% with molasses + gypsum. Electrical conductivity (EC 1:5) was 0.1 and 1.9 dS/m, pH1:5 in water was 7.7 and 7.1, and ESP was 4.1 and 0.2 in the control and molasses + gypsum treatments respectively. In the Proserpine soil, the amounts of dispersible clay were much less than in the Burdekin soil. The effects of molasses and gypsum in decreasing spontaneous and mechanical clay dispersion were similar to those in the Burdekin soil, but less pronounced. Molasses and gypsum, either alone or combined, improved the structural stability of both soils by decreasing dispersion and/or slaking. An implication of this work is that molasses may be a useful ameliorant for sodic soils, either alone or combined with gypsum.

INFLUENCE OF ICE SEGREGATION AND SOLUTES ON SOIL STRUCTURAL STABILITY

1990 ◽  
Vol 70 (4) ◽  
pp. 571-581 ◽  
Author(s):  
E. PERFECT ◽  
W. K. P. van LOON ◽  
B. D. KAY ◽  
P. H. GROENEVELT
Keyword(s):  
Water Content ◽  
Structural Stability ◽  
Aggregate Stability ◽  
Frost Heave ◽  
Unfrozen Water Content ◽  
Soil Structural Stability ◽  
Frost Penetration ◽  
Wet Aggregate Stability ◽  
Dispersible Clay ◽  
Ice Segregation

Most Canadian soils contain dissolved salts and are subject to freezing. However, the structural consequences of freezing in the presence of solutes are unknown. The effects of ice segregation and solutes on soil structural stability were investigated in a laboratory experiment. Nine 27-cm-diameter by 19-cm-high columns were used. These were packed with air-dry Conestogo silt loam soil (Gleyed Melanic Brunisol or Aquic Eutrochrept) and wetted with CaCl2 solutions at 1, 2, and 4 g L−1. Slow freezing took place from the top down in an environmental chamber maintained at −3.4 ± 0.4 °C. Depth of frost penetration, temperature, frost heave, and unfrozen water content were monitored within each column. After 20 d, the mean frost penetration was 107 ± 18 mm and the soil surface had heaved 9 ± 4 mm, indicating ice segregation. At the end of the experiment, the frozen and unfrozen zones of each column were sampled destructively. Samples were equilibrated at 4 °C and analyzed for wet-aggregate stability (WAS), dispersible clay (DC), gravimetric water content, and CaCl2 concentration. Samples which had been frozen had significantly more water and CaCl2 in the thawed state than those which had remained unfrozen. These increases were attributed to a freezing-induced redistribution of the saturating solutions. DC decreased with increasing CaCl2 concentration, indicating an electrical double-layer effect. Soil that had been frozen and thawed had a more stable structure (in terms of both DC and WAS) than the unfrozen soil. No interaction was found between solutes and freezing. In contrast, there was a significant interaction between water content and freezing. WAS increased with decreasing water content for those aggregates which had been frozen and thawed, but not for those which had remained unfrozen. Key words: Soil structure, wet-aggregate stability, dispersible clay, frost heave, soil solution, bulk electrical conductivity

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

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

Changes in dispersible clay content, organic carbon content, and electrolyte composition following incubation of sodic soil

Soil Research ◽  
1998 ◽  
Vol 36 (6) ◽  
pp. 883 ◽  
Author(s):  
P. N. Nelson ◽  
J. A. Baldock ◽  
J. M. Oades
Keyword(s):  
Organic Carbon ◽  
Carbon Content ◽  
Water Content ◽  
Clay Content ◽  
Electrolyte Composition ◽  
Organic Carbon Content ◽  
Sodic Soils ◽  
Sodic Soil ◽  
Clay Dispersion ◽  
Dispersible Clay

Measurement of dispersible clay is important for the diagnosis of structural stability problems in soil. However, clay dispersibility is known to change with water content and time. The purpose of the present study was to determine how incubation of sodic soil under different water content regimes influences clay dispersibility. Two topsoils (depth 0-0·1 m), one sodic [exchangeable sodium percentage (ESP) 9 · 7] and the other non-sodic (ESP 3·8), were collected from an experimental pasture at Kyabram, Victoria, and 2 soils, a sodic topsoil (depth 0-0·1 m, ESP 6·9) and the corresponding subsoil (depth 0·2-0 m, ESP 25·7), were collected from a cropped field at Two Wells, South Australia. The soils were incubated for 264 days in a split-plot design. The main treatments were soil type and incubation water content: continuously air-dry, continuously wet (-50 kPa), or with wet/dry cycles. The subtreatment was water content at analysis: air dry or wet (-50 kPa). Clay dispersion was greater when measured on wet soils than dry soils, irrespective of water contents during the prior incubation. Electrical conductivity increased, and sodium adsorption ratio (SAR), pH, and organic carbon content decreased as a function of the time for which the soils were wet. In the Kyabram soils that were wet when analysed, easily dispersible clay content increased with SAR. Decreases in moderately dispersible clay under the wetting/drying regime were not related to electrolyte composition, and were attributed to particle rearrangement and cementation. The decreases in clay dispersibility with time occurred despite net losses of carbohydrate and aliphatic materials. An implication of the work is that the decomposition of soil organic matter, even in the absence of fresh additions, may reduce clay dispersion in sodic soils by altering electrolyte concentration and composition.

Comparison of the effects of latex and poly(DADMAC) on structural stability and strength of soil aggregates

Soil Research ◽  
1995 ◽  
Vol 33 (2) ◽  
pp. 369 ◽  
Author(s):  
SM Bernas ◽  
JM Oades ◽  
GJ Churchman ◽  
CD Grant
Keyword(s):  
Structural Stability ◽  
Cropping Systems ◽  
Soil Aggregates ◽  
Aggregate Stability ◽  
Structural Condition ◽  
Mechanical Action ◽  
Water Stable Aggregates ◽  
The Face ◽  
Wet Aggregate Stability ◽  
Aromatic Oils

Two types of high molecular weight polymers having contrasting charge properties and molecular shapes [latex and poly(DADMAC)] were applied at different rates to three Alfisols and a Mollisol to examine the effects of these polymers on soil strength and structural stability, and to identify some of the mechanisms by which these polymers act to stabilize soils. Wet aggregate stability, mechanically dispersible clay, and soil friability tests were used to assess treatment effects, which were found to be greatest in soils having a poor structural condition. Each polymer acted differently. Latex, which acted like a coat of paint (because of its inability to penetrate beyond the surface of aggregates), dramatically increased the proportion of water stable aggregates >2 mm in all soils examined, and this was achieved without the traditional (expensive) use of aromatic oils and stabilizers. The latex coating produced a conglomeration of smaller soil aggregates, but did not extensively alter either the dispersibility of the aggregates in the face of mechanical action, or their strength and friability. Results indicate latex may be best suited to minimum tillage cropping systems. Poly(DADMAC), by contrast, was capable of entering most pores accessible to water. This enabled it to minimize clay dispersion, increase soil friability, and to modestly increase the size of water stable aggregates. In many ways, poly(DADMAC) would appear to be an ideal soil conditioner, although the economic suitability of this polymer and its effects on erosion control and plant growth have yet to be assessed.

Aggregate stability of salt-affected kaolinitic soils on the North-east Plateau, Thailand

Soil Research ◽  
2009 ◽  
Vol 47 (7) ◽  
pp. 697 ◽  
Author(s):  
C. Kaewmano ◽  
I. Kheoruenromne ◽  
A. Suddhiprakarn ◽  
R. J. Gilkes
Keyword(s):  
Electrical Conductivity ◽  
Aggregate Stability ◽  
Clay Content ◽  
Soil Samples ◽  
Exchangeable Sodium Percentage ◽  
Exchangeable Sodium ◽  
Sodic Soils ◽  
North East ◽  
The North ◽  
Sodium Percentage

The aggregate stability of 56 salt-affected soil samples from the North-east Plateau, Thailand, was related to soil properties. The soils were Typic Natraqualfs and a Typic Endoaqualf, which are commonly used for paddy rice cultivation. The soil textures are mostly clays and clay loams with clay contents ranging from 313 to 849 g/kg. The dominant mineral in the clay fraction is kaolinite with minor smectite and traces of illite and a little quartz. Aggregate stability of these soils, measured by the wet sieving method, ranges from 3 to91%. Electrical conductivity measured by the saturation extract method ranges from 0.6 to 16.2 dS/m and exchangeable sodium percentage ranges from 5 to 31%, so that the soil samples can be variously classed as saline, sodic, saline–sodic, and normal. The soil property that is most strongly correlated with aggregate stability is pH (r = –0.84) followed by exchangeable potassium (r = +0.75), cation exchange capacity (r = +0.73), clay content (r = +0.72), extractable acidity (r = +0.66), and organic matter (r = +0.66). However contrary to much published literature, no significant relationships exist between aggregate stability and exchangeable sodium percentage, sodium adsorption ratio, or electrical conductivity. Multivariate stepwise regression analyses indicated that aggregate stability of these mostly saline–sodic soils was well predicted by a combination of soil pH and clay content, which is convenient as they are properties determined in routine soil surveys. The presence of small amounts of smectite and illite may have reduced the stability of the dominantly kaolinitic soil aggregates.

Nature of the clay - cation bond affects soil structure as verified by X-ray computed tomography

Soil Research ◽  
2012 ◽  
Vol 50 (8) ◽  
pp. 638 ◽  
Author(s):  
Alla Marchuk ◽  
Pichu Rengasamy ◽  
Ann McNeill ◽  
Anupama Kumar
Keyword(s):  
Computed Tomography ◽  
Hydraulic Conductivity ◽  
Zeta Potential ◽  
Structural Stability ◽  
Structural Parameters ◽  
Pore Connectivity ◽  
X Ray ◽  
Clay Dispersion ◽  
X Ray Computed ◽  
Cation Ratio

Non-destructive X-ray computed tomography (µCT) scanning was used to characterise changes in pore architecture as influenced by the proportion of cations (Na, K, Mg, or Ca) bonded to soil particles. These observed changes were correlated with measured saturated hydraulic conductivity, clay dispersion, and zeta potential, as well as cation ratio of structural stability (CROSS) and exchangeable cation ratio. Pore architectural parameters such as total porosity, closed porosity, and pore connectivity, as characterised from µCT scans, were influenced by the valence of the cation and the extent it dominated in the soil. Soils with a dominance of Ca or Mg exhibited a well-developed pore structure and pore interconnectedness, whereas in soil dominated by Na or K there were a large number of isolated pore clusters surrounded by solid matrix where the pores were filled with dispersed clay particles. Saturated hydraulic conductivities of cationic soils dominated by a single cation were dependent on the observed pore structural parameters, and were significantly correlated with active porosity (R2 = 0.76) and pore connectivity (R2 = 0.97). Hydraulic conductivity of cation-treated soils decreased in the order Ca > Mg > K > Na, while clay dispersion, as measured by turbidity and the negative charge of the dispersed clays from these soils, measured as zeta potential, decreased in the order Na > K > Mg > Ca. The results of the study confirm that structural changes during soil–water interaction depend on the ionicity of clay–cation bonding. All of the structural parameters studied were highly correlated with the ionicity indices of dominant cations. The degree of ionicity of an individual cation also explains the different effects caused by cations within a monovalent or divalent category. While sodium adsorption ratio as a measure of soil structural stability is only applicable to sodium-dominant soils, CROSS derived from the ionicity of clay–cation bonds is better suited to soils containing multiple cations in various proportions.

scholarly journals Factors affecting clay dispersion in oxisols treated with vinasse

2016 ◽  
Vol 37 (6) ◽  
pp. 3997 ◽  
Author(s):  
Thadeu Rodrigues de Melo ◽  
Tiago Santos Telles ◽  
Walquiria Silva Machado ◽  
João Tavares Filho
Keyword(s):  
Sandy Soil ◽  
Physical Quality ◽  
Factors Affecting ◽  
Clay Dispersion ◽  
Water Dispersible ◽  
Dispersive Effect ◽  
Bivalent Cations ◽  
Chemical Attributes ◽  
Almost All ◽  
Dispersible Clay

Vinasse is a potassium-rich waste generated in large amounts by the ethanol production that, applied in the soil, can promote changes in water dispersible clay and in its physical quality. The aim of this study was to evaluate the clay dispersion of Oxisols after vinasse application and correlate it with some chemical attributes. Samples were collected in two Oxisols (155 and 471 g of clay kg-1), put in pots, received dosages of vinasse (0, 50, 100, 150 and 200 m3 ha-1) and remained incubated during 120 days. Phosphorous, organic carbon, pH H2O, pH KCl, pH CaCl2, Al3+, H+Al3+, Ca2+, Mg2+, K+, Na+, Delta pH and the proportion between monovalent and bivalent cations have been evaluated and correlated with the clay flocculation degree. Vinasse changed almost all chemical variables in both soils and increased the flocculation in the sandy soil, but did not change the clayey one. Delta pH, Mg2+ and K+ significantly correlated with the flocculation degree in the sandy soil. It is possible to conclude that the dispersive effect of K+ added by vinasse are irrelevant, considering the flocculant effect caused by the increment in Mg2+ and Delta pH after vinasse application.

Amelioration of sodic soils with blue-green algae

Soil Research ◽  
1981 ◽  
Vol 19 (3) ◽  
pp. 361 ◽  
Author(s):  
D Subhashini ◽  
BD Kaushik
Keyword(s):  
Electrical Conductivity ◽  
Hydraulic Conductivity ◽  
Nitrogen Content ◽  
Total Nitrogen ◽  
Algal Growth ◽  
Algal Flora ◽  
Exchangeable Sodium ◽  
Sodic Soils ◽  
Blue Green Algae ◽  
Biological Input

Algal growth resulted in significant reductions in pH, electrical conductivity, exchangeable sodium and in hydraulic conductivity and aggregation status of the soil. There was a significant increase in the total nitrogen content of the soil due to algal growth. Two out of the three inoculated species of algae could establish in the pots along with the indigenous algal flora. Combination of gypsum and algal application were found to have appreciable reclamative properties, and the possibility of using algae as a biological input for the reclamation of sodic soils has been indicated.

scholarly journals Quantitative and qualitative comparison of three wet aggregate stability methods using a long-term tillage system and crop rotation experiment

2018 ◽  
Vol 98 (4) ◽  
pp. 738-742 ◽  
Author(s):  
L.L. Van Eerd ◽  
A.H. DeBruyn ◽  
L. Ouellette ◽  
D.C. Hooker ◽  
D.E. Robinson
Keyword(s):  
Capital Investment ◽  
Surface Soil ◽  
Aggregate Stability ◽  
Clay Loam Soil ◽  
Qualitative Comparison ◽  
No Till ◽  
Tillage System ◽  
Loam Soil ◽  
Wet Aggregate Stability

Automated wet-sieving is preferred for this clay loam soil due to better sensitivity and savings (time and disposables) despite a larger capital investment. Rotations with greater frequency of winter wheat and no-till compared with conventional plow system had greater wet aggregate stability values, indicating better surface soil quality.

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