MACROAGGREGATION OF A PALEUDALF AFFECTED BY CAVITATION INTENSITY AND MANAGEMENT SYSTEMS WITH COVER PLANTS

Ultrasonic-based techniques allow the prediction of the energy required to break the aggregate and have been more commonly used to measure the stability of aggregates. Although they result in the same applied energy, certain combinations of time and power might correspond to different intensities of cavitation. Consequently, different responses in aggregation indexes can be obtained with different configurations of ultrasound techniques. Thus, this work was carried out to evaluate the effects of cavitation intensity in the distribution of aggregates of a Paleudalf under management systems with cover plants and to compare aggregate stability determination methods (ultrasound versus wet sieving). Aggregate samples of the BS (bare soil), OT (black oat + forage turnips) and OV (black oat + hairy vetch) treatments were exposed to ultrasonic irradiation in different combinations of potency and time: (U1) 74.5 W/4 s; (U2) 49.7 W/6 s; (U3) 74.5 W/10 s and (U4) 49.7 W/15 s. After each sonification, the samples were passed in the same set of sieves used in the standard method of wet sieving -WS (8.00 - 4.76, 4.76 - 2.00, 2.00 - 1.00, 1.00 - 0.25 and < 0.25 mm) and the geometric mean diameter (GMD) and mass-weighted mean diameter (WMD) were calculated. The amplitude of vibration exerted a greater influence on soil breakdown than the total energy applied. Compared to the ultrasound method, in the WS method observed higher percentage of retained aggregates in the size class 8-4.76 mm and, consequently, greater aggregation indexes GMD and WMD.

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Effect of soil organic carbon loss on the stability and structure of microaggregates: First insights from an organic carbon depletion field trial in a loess soil

10.5194/egusphere-egu21-9266 ◽

2021 ◽

Author(s):

Svenja Roosch ◽

Vincent Felde ◽

Daniel Uteau ◽

Stephan Peth

Keyword(s):

Organic Carbon ◽

Soil Organic Carbon ◽

Aggregate Stability ◽

Loess Soil ◽

Bulk Soil ◽

Undisturbed Soil ◽

Ap Horizon ◽

The Stability ◽

Shed Light ◽

Wet Sieving

Soil microaggregates are considered to play an important role in soil functioning and soil organic carbon (SOC) is of great importance for the formation and stabilization of these aggregates. The loss of SOC can occur, for example, after a change in land use and may lead to a decreased aggregate stability, which makes soils vulnerable to various threats, such as erosion or compaction. It is therefore important to shed light on the effect of SOC loss on aggregate stability in order to better understand and preserve the functioning of healthy soils.We sampled two adjacent plots from a loess soil in Selhausen (Germany) and measured aggregate stability and architecture of soil microaggregates. One plot was kept free from vegetation by the application of herbicides and by tillage (to a depth of 5 cm) from 2005 on (organic matter depletion, OMD), while the other plot was used for agriculture using conventional tillage (control). Over the course of 14 years, the SOC concentration in the bulk soil has been reduced from 12.2 to 10.1 g SOC kg-1 soil. It was, however, unclear whether a loss of SOC had also taken place in microaggregates (since they are known to have very long turnover times). We took 10 undisturbed soil cores from two depths of each plot (Ap and Bt horizons).The stability of aggregates against hydraulic and mechanical stresses was tested using wet sieving&#160; (mesh sizes of 0.25 to 8 mm) and a crushing test in a load frame adapted to the microaggregate scale. For the latter test, microaggregates were isolated from the bulk soil using a newly developed dry crushing approach. To shed light on the effect of a decreased SOC content on microaggregate structure, we scanned several microaggregates with a computed tomography scanner at sub-micron resolution and analysed the features of their pore systems. SOC losses had also occurred in large&#160; microaggregates (250-53 &#181;m) in the Ap horizon: SOC contents in this fraction were 16.3 g SOC kg&#8315;&#185; (control) and 12.8 g SOC kg&#8315;&#185; (OMD). While wet sieving indicated a lower stability of macroaggregates from the Ap horizon in the OMD plot (geometric mean diameter: 1.54 mm (control) vs 0.43 mm (OMD)), an effect on the tensile strength of large microaggregates could not be found. Total porosity and pore connectivity, derived from Euler characteristic, as well as several pore skeleton traits (number of branches, junctions, etc.) were lower in aggregates from the OMD treatment. However, the difference was also present or even stronger in the Bt horizon than in the Ap horizon, so the supposed treatment effect might have been due to other effects like spatial heterogeneity of texture. Thus, the observed SOC losses may not have been large enough to substantially influence struture or stability of large microaggregates.

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Aggregate stability as affected by short and long-term tillage systems and nutrient sources of a hapludox in southern Brazil

Revista Brasileira de Ciência do Solo ◽

10.1590/s0100-06832009000400003 ◽

2009 ◽

Vol 33 (4) ◽

pp. 767-777 ◽

Cited By ~ 15

Author(s):

Milton da Veiga ◽

Dalvan José Reinert ◽

José Miguel Reichert

Keyword(s):

Organic Matter ◽

Crop Residues ◽

Geometric Mean ◽

Organic Matter Content ◽

Aggregate Stability ◽

Matter Content ◽

Tillage Systems ◽

Soil Layers ◽

Nutrient Sources ◽

Mean Diameter

The ability of a soil to keep its structure under the erosive action of water is usually high in natural conditions and decreases under frequent and intensive cultivation. The effect of five tillage systems (NT = no-till; CP = chisel plowing and one secondary disking; CT = primary and two secondary distings; CTb = CT with crop residue burning; and CTr = CT with removal of crop residues from the field), combined with five nutrient sources (C = control, no nutrient application; MF = mineral fertilizers according to technical recommendations for each crop; PL = 5 Mg ha-1 y-1 fresh matter of poultry litter; CM = 60 m³ ha-1 y-1 slurry cattle manure; and SM = 40 m³ ha-1 y-1 slurry swine manure) on wet-aggregate stability was determined after nine years (four sampled soil layers) and on five sampling dates in the 10th year (two sampled soil layers) of the experiment. The size distribution of the air-dried aggregates was strongly affected by soil bulk density, and greater values of geometric mean diameter (GMD AD) found in some soil tillage or layer may be partly due to the higher compaction degree. After nine years, the GMD AD on the surface was greater in NT and CP compared to conventional tillage systems (CT, CTb and CTr), due to the higher organic matter content, as well as less soil mobilization. Aggregate stability in water, on the other hand, was affected by the low variation in previous gravimetric moisture of aggregates, which contributed to a high coefficient of variation of this attribute. The geometric mean diameter of water-stable aggregates (GMD WS) was highest in the 0.00-0.05 m layer in the NT system, in the layers 0.05-0.10 and 0.12-0.17 m in the CT, and values were intermediate in CP. The stability index (SI) in the surface layers was greater in treatments where crop residues were kept in the field (NT, CP and CT), which is associated with soil organic matter content. No differences were found in the layer 0.27-0.32 m. The effect of nutrient sources on GMD AD and GMD WS was small and did not affect SI.

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Biological soil crusts mediate changes in soil aggregate stability along a climate gradient in Chile

10.5194/egusphere-egu21-7914 ◽

2021 ◽

Author(s):

Nicolás Riveras Muñoz ◽

Steffen Seitz ◽

Corinna Gall ◽

Hugo Pérez ◽

Peter Kuehn ◽

...

Keyword(s):

Geometric Mean ◽

Aggregate Stability ◽

Soil Surface ◽

Soil Aggregate ◽

Biological Soil Crusts ◽

Soil Aggregate Stability ◽

Climate Gradient ◽

Soil Crusts ◽

Stabilizing Effect ◽

The Stability

Biological soil crusts (biocrusts) composed of cyanobacteria, algae, lichens and bryophytes have a stabilizing effect on the soil surface. This effect is mostly studied in arid climates, where biocrusts are the main biological agent to steady and bind together soil aggregates. Nevertheless, biocrusts are also an integral part of the soil surface under semi-humid and humid climate conditions, mainly covering open spaces in forests and on fallow lands. As such, they often develop after vegetation disturbances, when their ability to compete with higher plants is increased. To better understand how biocrusts mediate changes in soil aggregate stability under different climatic conditions, we analyzed soil substrates taken under biocrust communities from four national parks in Chile using dry and wet sieving. These samples cover soils from a large climate gradient from arid (Pan de Az&#250;car), semiarid (Santa Gracia), mediterranean (La Campana) to humid (Nahuelbuta).&#160; Biocrust communities were dominated by cyanobacteria in Pan de Az&#250;car and Santa Gracia, bryophytes and lichens in La Campana and bryophytes in Nahuelbuta. They showed a stabilizing effect on the soil surface in three of the four investigated climates. Their presence increased the Mean Weight Diameter of the aggregates (MWD) by 102% in Pan de Az&#250;car, 208% in Santa Gracia and 82% in La Campana. In Nahuelbuta there was no significant increase to the condition without biocrust, because the abundance of permanent soil covering higher vegetation does not allow the effect of biocrusts to manifest. The stabilization differed between the aggregate fractions studied, being most pronounced for smaller aggregates >2 mm. The Geometric Mean Diameter (GMD) showed similar results as MWD, but with a clear effect of drying and wetting conditions, as an increase in the stability directly related to precipitation and the climatic gradient. Bulk density (BD) changed from high mean values of 1.50 g cm-3 in Pan de Az&#250;car and 1.63 g cm-3 in Santa Gracia (where cattle grazing was observed) to 1.16 g cm-3 in La Campana and the lowest mean of 0.62 g cm-3 in Nahuelbuta, where we observed a more developed soil structure and high organic matter content (21.58% in average). Accordingly, here we also found pronounced hydrophobicity of the soil. These preliminary findings indicate not only differences in the stability of the aggregates, but also in the state of conservation and management of the soils. Results will now be extended by further statistical analyses, which will additionally be presented at vEGU21.

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EDAPHIC ATTRIBUTES OF A CROP-LIVESTOCK INTEGRATION SYSTEM IN THE CERRADO BIOME

Revista Caatinga ◽

10.1590/1983-21252016v29n414rc ◽

2016 ◽

Vol 29 (4) ◽

pp. 892-900 ◽

Cited By ~ 2

Author(s):

SIDINEI JULIO BEUTLER ◽

MARCOS GERVASIO PEREIRA ◽

ARCÂNGELO LOSS ◽

ADRIANO PERIN ◽

CRISTIANE FIGUEIRA DA SILVA

Keyword(s):

Soil Aggregates ◽

Geometric Mean ◽

Aggregate Stability ◽

Farming Systems ◽

Cerrado Biome ◽

Cerrado Vegetation ◽

Urochloa Decumbens ◽

Tillage System ◽

Pasture Area ◽

The Stability

ABSTRACT A significant increase in the use of integrated farming systems have been observed in the Brazilian Cerrado, such as crop-livestock integration (CLI), which combined with the no-tillage system (NTS) have shown significant influence on soil properties. Therefore, the objective of this work was to evaluate the influence of a CLI system on the chemical, physical and microbiological soil characteristics, in an area in the Cerrado biome, Montividiu, State of Goias, Brazil. The soil fertility, remaining phosphorus (Prem), total organic carbon (TOC), total nitrogen (Nt), aggregate stability (geometric mean diameter - GMD), microbial respiration (C-CO2) and easily-extractable glomalin-related soil protein (EE-GRSP) were evaluated. Soil samples were collected at depth of 0-5 and 5-10 cm in three areas with: CLI (13 years of annual rotation with Urochloa ruziziensis); Urochloa decumbens pasture (15 years of implementation); and native Cerrado vegetation. The CLI area had higher pH, Mg, P available (0-10 cm) and Prem (5-10 cm) values compared to the other areas, and equal values of TOC, Nt, EE-GRSP (0-10 cm) and aggregate stability (5-10 cm) compared to the pasture area. The CLI had no differences in C-CO2 emissions compared to the Cerrado, but had lower rates compared to the pasture. The P available and Prem were sensitive indicators to show the differences between the CLI and pasture systems, with higher contents in the CLI area. The TOC and Nt indicators had no differences between these two systems. The GMD results indicated a better aggregation in the pasture (0-5 cm) compared to the CLI area, while the EE-GRSP were similar in these areas. The total values of C-CO2 emission from the soil aggregates showed the stability of respirometry rates in the CLI and Cerrado areas.

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Effect of Stability of Soil Water-Stable Aggregates under Different Land Use

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.518-523.4026 ◽

2012 ◽

Vol 518-523 ◽

pp. 4026-4029

Author(s):

Hong Zheng ◽

Yan Dong Zhang

Keyword(s):

Land Use ◽

Secondary Forest ◽

Soil Aggregates ◽

Geometric Mean ◽

Land Use Patterns ◽

Natural Secondary Forest ◽

Use Patterns ◽

Water Stable Aggregates ◽

Mean Diameter ◽

The Stability

Using the Northeast region for the study area as it has a typical different land use types, through the soil sampling and analysis, research and compare different land use distribution of soil aggregates. The results showed that among different land use patterns, the surface (0 ~ 20 cm) has the maximum of water stable aggregates <0.25mm (up to 52.262%). Whether it is farmland or plantations, subsurface soil aggregates are higher than the surface aggregates content, but showing natural secondary forest soil structure has the stability characteristics that natural secondary forest water-stable aggregate content has no significant effect; soil aggregates average body weight diameter and geometric mean diameter, the surface fields are the lowest, the use of forest land into farmland, the mean weight diameter and geometric mean diameter, has declined. In general, the surface 0 ~ 20 cm is higher than the subsurface 20 ~ 40 cm.

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Soil aggregation as influenced by cultural practices in Saskatchewan: II. Brown and Dark Brown Chernozemic soils

Canadian Journal of Soil Science ◽

10.4141/cjss93-058 ◽

1993 ◽

Vol 73 (4) ◽

pp. 597-612 ◽

Cited By ~ 10

Author(s):

C. A. Campbell ◽

D. Curtin ◽

R. P. Zentner ◽

S. Brandt

Keyword(s):

Nutrient Dynamics ◽

Management Practices ◽

Crop Residues ◽

Geometric Mean ◽

Aggregate Stability ◽

Soil Disturbance ◽

Water Infiltration ◽

Chernozemic Soil ◽

Mean Diameter ◽

Erodible Fraction

The size distribution and stability of aggregates are important characteristics influencing tilth, erosion, water infiltration and nutrient dynamics in soil. We need to understand how soil management influences agregation so that we may make suitable modifications to farming practices to enhance soil stability. Two long-term crop-rotation experiments in southern Saskatchewan were used to examine the effects of management on aggregation. In 1991, soil was collected three times during the summer from the top 5 cm of soil as part of a 25-yr experiment at Swift Current (Orthic Brown Chernozemic soil) and twice as part of a 27-yr experiment at Scott (Orthic Dark Brown Chernozemic soil). The two medium-textured soils were dry-sieved by rotary sieve and then wet-sieved after (i) slow wetting and (ii) fast wetting of the 1–2-mm size fractions. The wind-erodible fraction (<0.84 mm) of soil and geometric mean diameter (GMD) of aggregates varied with antecedent precipitation. Thus, wind-erodible aggregates increased at both sites, even in cropped rotation phases, when conditions were dry during the last 6 wk of the 1991 summer. However, the presence of crops and management practices that increased crop residues (e.g., fertilizers) tended to reduce the wind-erodible fraction and increase GMD. A very close relationship existed between the wind-erodible fraction (y) and GMD at the two sites: y = 16.2 + 105/GMD, (r2 = 0.95***) for the pooled data for the two sites. In contrast to results for the wind-erodible fraction, dry growing-season weather conditions tended to increase the water stability of aggregates. Fast wetting was more effective than slow wetting in delineating management effects on aggregate stability. Aggregate stability was increased by frequent cropping and by adequate fertilization, presumably as a result of increased production of crop residues. At Swift Current, chemical fallow increased aggregate stability, likely as a result of reduced soil disturbance. Key words: Wet sieving, dry sieving, crop rotations, erodibility, geometric mean diameter, meteorological conditions

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Spatial variability of aggregate stability in latosols under sugarcane

Revista Brasileira de Ciência do Solo ◽

10.1590/s0100-06832009000200002 ◽

2009 ◽

Vol 33 (2) ◽

pp. 245-253 ◽

Cited By ~ 8

Author(s):

Zigomar Menezes de Souza ◽

José Marques Júnior ◽

Gener Tadeu Pereira ◽

Carolina Maria Sánchez Sáenz

Keyword(s):

Organic Matter ◽

Spatial Variability ◽

Management System ◽

Geometric Mean ◽

Aggregate Stability ◽

Variation Coefficient ◽

Mean Weight Diameter ◽

Mean Diameter ◽

Lower Variation ◽

Red Latosol

The spatial variability of soils under a same management system is differentiated, as expressed in the properties. The spatial variability of aggregate stability of a eutrophic Red Latosol (ERL) and a dystrophic Red Latosol (DRL) under sugarcane was characterized. Samples were collected in a regular 10 m grid, in the layers 0.0-0.2 and 0.2-0.4 m, with 100 points per area, and the following properties were determined: geometric mean diameter (GMD) of aggregates, mean weight diameter (MWD) of aggregates, percent of aggregates in the > 2.0 mm class and organic matter (OM) content. The eutrophic Red Latosol (ERL) had a higher aggregate stability thn the dystrophic Red Latosol (DRL), which may be attributed to the higher clay and OM content and the gibbsitic mineralogy of this soil class. The differentiated evolution of the studied Oxisols explains the wider range and lower variation coefficient and variability, for all properties studied in the eutrophic Red Latosol.

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Spatial Variability in Stability of Aggregates and Organic Matter of an Oxisol

Journal of Agricultural Science ◽

10.5539/jas.v10n8p328 ◽

2018 ◽

Vol 10 (8) ◽

pp. 328

Author(s):

Ismênia Ribeiro De Oliveira ◽

Jussara Silva Dantas ◽

Letícia Da Silva Ribeiro ◽

James Ribeiro De Azevedo ◽

Lauter Silva Souto ◽

...

Keyword(s):

Organic Matter ◽

Spatial Variability ◽

Geometric Mean ◽

Conventional Tillage ◽

No Tillage ◽

Important Indicator ◽

Spatially Correlated ◽

Rectangular Mesh ◽

Mean Diameter ◽

The Stability

Soil preparation may break its structure, destabilize the aggregates, and cause the loss of organic matter (OM). The study of spatial variability of soil attributes is an important indicator of soil physical quality. The aim of this study was to describe the spatial variability of the stability of aggregates and organic matter in Oxisol (Yellow Latosol) under different management systems.We collected simple samplings of soil in the eastern mesoregion of Maranhão, Brazil. Experimental areas with two distinct management systems were studied: conventional tillage and no-tillage. In each experimental area, we fitted a rectangular mesh of 50 points with 40m of spacing and 0.00 to 0.20 mof depth. The response variables were: weighted mean diameter (WMD); geometric mean diameter (GMD); percentage of aggregates (on classes of size between 1-2 mm and above 2 mm); and organic matter (OM). The no-tillage management showed high values of WMD, GMD, class of aggregates and OM. Maps of WMD and GMD were spatially correlated to OM map at no-tillage management. Soil properties had a spatial-dependent structure. The management system influenced the stability of aggregates and the amount of organic matter.

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Characteristics and Stability of Soil Aggregates in Tea Plantation

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.343-344.968 ◽

2011 ◽

Vol 343-344 ◽

pp. 968-974

Author(s):

Zi Cheng Zheng ◽

Ting Xuan Li ◽

Shu Qin He

Keyword(s):

Soil Aggregates ◽

Geometric Mean ◽

Aggregate Stability ◽

Stability Index ◽

Soil Aggregate ◽

Tea Plantation ◽

Soil Aggregate Stability ◽

Mean Weight Diameter ◽

Eucalyptus Plantations ◽

Wet Sieving

Soil aggregate stability as a key indicator of soil structure and erodibility to evaluate soil stability, is a product of interactions between soil environment, management practices, and land use patterns. The objective of this study was to analyze the distribution characteristics, characteristics of fractal features and stability of soil aggregates in tea plantations and eucalyptus plantations of Western Sichuan in China. The dry- and water-stable aggregate size distributions were determined by dry sieving and wet sieving methods. The results showed that soil structural properties in tea and eucalyptus plantations were similar. With increase in depth of soil layer, the aggregate stability of tea plantation soil became stronger. Comparative analysis of dry and wet sieving results showed that most of the aggregates in tea plantation soil were unstable. The soil aggregates >5mm and 0.5-0.25mm in size had higher stability, while those 2-1mm in size had lower stability. For tea plantation soil, the correlation coefficients between aggregate stability index and mean weight diameter, geometric mean diameter, fractal dimension were bigger under wet sieving than those under dry sieving. The results showed that aggregate stability index, mean weight diameter, geometric mean diameter, fractal dimension of water-stable aggregates could characterize soil aggregate stability in tea plantation ideally.

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Morphology and stability of aggregates of an Oxisol according to tillage system and gypsum application

Revista CERES ◽

10.1590/s0034-737x2012000600017 ◽

2012 ◽

Vol 59 (6) ◽

pp. 859-866 ◽

Cited By ~ 2

Author(s):

Fábio Régis de Souza ◽

Edgard Jardim Rosa Junior ◽

Carlos Ricardo Fietz ◽

Douglas Martins Pereira Pellin ◽

Anderson Cristian Bergamin ◽

...

Keyword(s):

Aggregate Stability ◽

Residual Effect ◽

Conventional Tillage ◽

Morphological Characterization ◽

Management Systems ◽

No Tillage ◽

Tillage System ◽

Aggregate Morphology ◽

The Stability ◽

Residual Action

Morphological characterization and aggregate stability is an important factor in evaluating management systems. The aim of this paper is to evaluate the stability and morphology of the aggregates of a dystrophic Oxisol managed with no-tillage and conventional tillage with and without the residual action of gypsum. The experimental design was randomized blocks arranged in split-split plot, where the treatments were two soil management systems (plots) with 0 and 2000 kg ha-1 of gypsum (subplots) and five depths (0-0.05, 0.05-0.10, 0.10-0.15, 0.15-0.20 and 0.20-0.30 m) as the subsubplots, with four replications. The aggregate morphology was determined through images and later evaluated by the Quantporo software. Stability was determined by the wet method. The results showed that the no-tillage system, with or without gypsum residual effect, provided the aggregates with the largest geometric diameters. The combination of no-tillage system and the gypsum residual effect provided rougher aggregates.

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