Factors Affecting Aggregate Stability and Water Dispersible Clay of Recently Cultivated Semiarid Soils of Argentina

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.

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Aggregate distribution, stability and release of water dispersible clay for two subtropical Oxisols

Scientia Agricola ◽

10.1590/s0103-90162007000100006 ◽

2007 ◽

Vol 64 (1) ◽

pp. 36-43 ◽

Cited By ~ 2

Author(s):

Antonio Carlos de Azevedo ◽

Darrel Gene Schulze

Keyword(s):

Aggregate Stability ◽

Conventional Tillage ◽

Native Vegetation ◽

Land Uses ◽

Soil Functions ◽

Soil Suspension ◽

Aggregate Distribution ◽

Water Dispersible ◽

Dispersible Clay ◽

Suspension Ph

The behavior of a soil regarding the dispersion and aggregation of its particles is very important for the development of environmental and agricultural soil functions. This study was conducted to determine how aggregate distribution and stability are impacted by land uses and how the release of Water Dispersible Clay (WDC) relates to disaggregation in Oxisols from subtropical Brazil. Samples from two Oxisols, collected at three depths from sites under no-tillage (NT), conventional tillage (CT) and native vegetation (NV) land uses were shaken in 250 mL plastic bottles for intervals up to 27 hours. The mass of aggregates was measured in five size classes ranging from 53 to 2000 µm. Most aggregates larger than 500 mm disappeared during the first 7.5 hours of shaking, concurrent with an increase in WDC release and without change in soil suspension pH and electrical conductivity, without increase in smaller aggregates. Therefore, there is no aggregate hierarchy in these soils and the release of WDC was caused by breaking aggregates within the 500 to 2000 mm range. Land uses affect mass of aggregates in each size class, but the aggregate stability depends on its size, not land use.

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Water-dispersible clay in soils treated with sewage sludge

Revista Brasileira de Ciência do Solo ◽

10.1590/s0100-06832010000500005 ◽

2010 ◽

Vol 34 (5) ◽

pp. 1527-1534 ◽

Cited By ~ 7

Author(s):

João Tavares Filho ◽

Graziela Moraes de Césare Barbosa ◽

Adriana Aparecida Ribon

Keyword(s):

Sewage Sludge ◽

Block Design ◽

Clay Fraction ◽

Organic Matter Content ◽

Soil Samples ◽

Point Of Zero Charge ◽

Native Forest ◽

Water Dispersible ◽

Significant Difference ◽

Dispersible Clay

A by-product of Wastewater Treatment Stations is sewage sludge. By treatment and processing, the sludge is made suitable for rational and environmentally safe use in agriculture. The aim of this study was to assess the influence of different doses of limed sewage sludge (50 %) on clay dispersion in soil samples with different textures (clayey and medium). The study was conducted with soil samples collected from native forest, on a Red Latosol (Brazilian classification: Latossolo Vermelho distroférrico) loamy soil in Londrina (PR) and a Red-Yellow Latosol (BC: Latossolo Vermelho-Amarelo distrófico) medium texture soil in Jaguapitã (PR). Pots were filled with 3 kg of air-dried fine earth and kept in greenhouse. The experiment was arranged in a randomized block design with six treatments: T1 control, and treatments with limed sewage sludge (50 %) as follows: T2 (3 t ha-1), T3 (6 t ha-1), T4 (12 t ha-1), T5 (24 t ha-1) and T6 (48 t ha-1) and five replications. The incubation time was 180 days. At the end of this period, the pots were opened and two sub-samples per treatment collected to determine pH-H2O, pH KCl (1 mol L-1), organic matter content, water-dispersible clay, ΔpH (pH KCl - pH-H2O) and estimated PZC (point of zero charge): PZC = 2 pH KCl - pH-H2O, as well as the mineralogy of the clay fraction, determined by X ray diffraction. The results showed no significant difference in the average values for water-dispersible clay between the control and the other treatments for the two soil samples studied and ΔpH was the variable that correlated best with water-dispersible clay in both soils.

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

Soil Research ◽

10.1071/sr9950975 ◽

1995 ◽

Vol 33 (6) ◽

pp. 975 ◽

Cited By ~ 124

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.

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FACTORS AFFECTING CLAY DISPERSION AND AGGREGATE STABILITY OF ARID-ZONE SOILS

Soil Science ◽

10.1097/00010694-198811000-00004 ◽

1988 ◽

Vol 146 (5) ◽

pp. 317-325 ◽

Cited By ~ 80

Author(s):

SABINE GOLDBERG ◽

D. L. SUAREZ ◽

R. A. GLAUBIG

Keyword(s):

Arid Zone ◽

Aggregate Stability ◽

Factors Affecting ◽

Clay Dispersion

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Soil aggregation under different management systems

Revista Brasileira de Ciência do Solo ◽

10.1590/s0100-06832012000600021 ◽

2012 ◽

Vol 36 (6) ◽

pp. 1868-1877 ◽

Cited By ~ 17

Author(s):

Cibele Mascioli Rebello Portella ◽

Maria de Fátima Guimarães ◽

Christian Feller ◽

Inês Cristina de Batista Fonseca ◽

João Tavares Filho

Keyword(s):

Chemical Properties ◽

Aggregate Stability ◽

Stability Index ◽

Conventional Tillage ◽

Soil Aggregation ◽

Natural State ◽

Native Forest ◽

Water Dispersible ◽

Soil Preparation ◽

And Chemical Properties

Considering that the soil aggregation reflects the interaction of chemical, physical and biological soil factors, the aim of this study was evaluate alterations in aggregation, in an Oxisol under no-tillage (NT) and conventional tillage (CT), since over 20 years, using as reference a native forest soil in natural state. After analysis of the soil profile (cultural profile) in areas under forest management, samples were collected from the layers 0-5, 5-10, 10-20 and 20-40 cm, with six repetitions. These samples were analyzed for the aggregate stability index (ASI), mean weighted diameter (MWD), mean geometric diameter (MGD) in the classes > 8, 8-4, 4-2, 2-1, 1-0.5, 0.5-0.25, and < 0.25 mm, and for physical properties (soil texture, water dispersible clay (WDC), flocculation index (FI) and bulk density (Bd)) and chemical properties (total organic carbon - COT, total nitrogen - N, exchangeable calcium - Ca2+, and pH). The results indicated that more intense soil preparation (M < NT < PC) resulted in a decrease in soil stability, confirmed by all stability indicators analyzed: MWD, MGD, ASI, aggregate class distribution, WDC and FI, indicating the validity of these indicators in aggregation analyses of the studied soil.

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