Comparison of four prewetting techniques in wet aggregate stability determination

1991 ◽  
Vol 71 (1) ◽  
pp. 67-72 ◽  
Author(s):  
E. L. Dickson ◽  
V. Rasiah ◽  
P. H. Groenevelt
Keyword(s):  
Key Words ◽  
Coefficient Of Variation ◽  
Treatment Effects ◽  
Soil Aggregates ◽  
High Vacuum ◽  
Aggregate Stability ◽  
Gas Pressure ◽  
Wet Aggregate Stability ◽  
Wetting Rate

Variabilities in measured values of wet aggregate stability (WAS) of replicate samples of treatment exceeding that between treatments can create problems in interpreting treatment effects. The variabilities in WAS of replicate samples of treatment can be minimized by subjecting soil aggregates to a high vacuum fast prewetting technique. However, this technique is laborious and time consuming. In this paper the effect of four prewetting techniques: (1) and (2) high vacuum fast (HVFW) and slow (HVSW) wetting; (3) and (4) no vacuum (atmospheric) fast (NVFW) and slow wetting (NVSW) on the variations in WAS and coefficient of variation (CV) of WAS are reported. The measured values in WAS and CV of WAS for each soil varied with wetting rate and/or gas pressure used. The highest variation in WAS was found with NVFW, HVFW, NVSW and HVSW, respectively. For three out of four soils, the CV of WAS for NVSW technique was less than 2%, which was similar to that obtained under HVFW technique. Compared to HVFW technique, NVSW technique is simple, less laborious and less time consuming. Key words: Wet aggregate stability, prewetting techniques, vacuum wetting.

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.

scholarly journals Dynamics of Soil Organic Carbon and Labile Carbon Fractions in Soil Aggregates Affected by Different Tillage Managements

2021 ◽  
Vol 13 (3) ◽  
pp. 1541
Author(s):  
Xiaolin Shen ◽  
Lili Wang ◽  
Qichen Yang ◽  
Weiming Xiu ◽  
Gang Li ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Soil Aggregates ◽  
Aggregate Stability ◽  
Soil Aggregate ◽  
No Tillage ◽  
Labile Carbon ◽  
Carbon Fractions ◽  
Soil Aggregate Stability ◽  
Positive Effects

Our study aimed to provide a scientific basis for an appropriate tillage management of wheat-maize rotation system, which is beneficial to the sustainable development of agriculture in the fluvo-aquic soil areas in China. Four tillage treatments were investigated after maize harvest, including rotary tillage with straw returning (RT), deep ploughing with straw returning (DP), subsoiling with straw returning (SS), and no tillage with straw mulching (NT). We evaluated soil organic carbon (SOC), dissolved organic carbon (DOC), permanganate oxidizable carbon (POXC), microbial biomass carbon (MBC), and particulate organic carbon (POC) in bulk soil and soil aggregates with five particle sizes (>5 mm, 5–2 mm, 2–1 mm, 1–0.25 mm, and <0.25 mm) under different tillage managements. Results showed that compared with RT treatment, NT treatment not only increased soil aggregate stability, but also enhanced SOC, DOC, and POC contents, especially those in large size macroaggregates. DP treatment also showed positive effects on soil aggregate stability and labile carbon fractions (DOC and POXC). Consequently, we suggest that no tillage or deep ploughing, rather than rotary tillage, could be better tillage management considering carbon storage. Meanwhile, we implied that mass fractal dimension (Dm) and POXC could be effective indicators of soil quality, as affected by tillage managements.

Soil Aggregates Stability of Forest Islands and Adjacent Ecosystems in West Africa

2021 ◽  
Vol 9 (2) ◽  
pp. 283
Author(s):  
Amelie Baomalgré Bougma ◽  
Korodjouma Ouattara ◽  
Halidou Compaore ◽  
Hassan Bismarck Nacro ◽  
Caleb Melenya ◽  
...  
Keyword(s):  
Land Use ◽  
West Africa ◽  
Agricultural Soils ◽  
Direct Action ◽  
Soil Aggregates ◽  
Aggregate Stability ◽  
Mean Annual Precipitation ◽  
Savanna Vegetation ◽  
Study Sites ◽  
Forest Islands

In the more mesic savanna areas of West Africa, many areas of relatively tall and dense vegetation with a species composition more characteristic of forest than savanna are often found around villages areas. These ‘forest islands’ may be the direct action of human activity. To better understand these patches with relatively luxuriant vegetation, our study focused on how they influence soil aggregation in comparison with nearby areas and natural savanna vegetation across a precipitation transect in West Africa for which mean annual precipitation at the study sites ranges from 0.80 to 1.27 m a-1. Soil samples were taken from 0 to 5 cm and 5 to 10 cm depths and aggregate groups with diameters: > 500 μm, 500-250 μm and 250-53 μm (viz. “macroaggregates”, “mesoaggregates” and “microaggregates”) determined using the wet sieving method. The results showed significantly higher proportion of stable meso and macroaggregates in forest islands and natural savanna compared to agricultural soils (p <0.05). On the other hand, although there was no effect of land-use type on microaggregates stability, there was a strong tendency for the microaggregate fraction across all land use types to increase with increasing precipitation. Soil organic carbon and iron oxides contents are the most important factors influencing aggregate stability in West African ecosystems. By increasing soil structural stability, forest islands contribute to soil erosion reduction and the control of land degradation.

Aggregate size distribution and stability of an oxisol under legume-based and pure grass pastures in the eastern Colombian savannas

Soil Research ◽  
1995 ◽  
Vol 33 (1) ◽  
pp. 153 ◽  
Author(s):  
AJ Gijsman ◽  
RJ Thomas
Keyword(s):  
Size Distribution ◽  
Soil Aggregates ◽  
Aggregate Stability ◽  
Aggregate Size ◽  
Soil Aggregate ◽  
Hot Water ◽  
Aggregate Size Distribution ◽  
Carbohydrate Concentration ◽  
Stability Measurement ◽  
Water Extractable

This study evaluated soil aggregate size distribution and stability of an Oxisol under improved grass-only or grass-legume pastures, established in previously native savanna. Three grass-legume combinations were included at various stocking rates. In all treatments and soil layers, soils were well aggregated, having more than 90% of their weight in macroaggregates (>250 �m). The addition of legumes to pastures did not affect the soil aggregate size distribution, although aggregates showed somewhat more stability against slaking. An increase in stocking rate negatively affected both average aggregate size and aggregate stability. Aggregates showed little or no dispersion of clay particles in any treatment. A positive correlation was found between wet aggregate stability and hot-water extractable carbohydrate concentration, supporting the hypothesis that these carbohydrates equate with plant-derived or microbial polysaccharides which glue soil aggregates together. It is suggested that determination of hot-water extractable carbohydrates may serve as a useful indicator of small differences in aggregate stability, even when these differences are not evident in the stability measurement itself.

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.

scholarly journals Soil uses in the sugarcane fallow period to improve chemical and physical properties of two latosols (oxisols)

2012 ◽  
Vol 36 (1) ◽  
pp. 283-294 ◽  
Author(s):  
Carolina Fernandes ◽  
José Eduardo Corá ◽  
Adolfo Valente Marcelo
Keyword(s):  
Physical Properties ◽  
Soil Aggregates ◽  
Block Design ◽  
Chemical Properties ◽  
Aggregate Stability ◽  
Fallow Period ◽  
Growing Seasons ◽  
Randomized Block Design ◽  
Sunn Hemp ◽  
In The Beginning

Sugarcane production should be integrated with crop diversification with a view to competitive and sustainable results in economic, social and environmental aspects. The purpose of this study was to assess the influence of different soil uses during the sugarcane fallow period on the chemical and physical properties of eutroferric Red Latosol - LVef (Oxisol) and Acric Latosol - LVw (Acric Oxisol), in Jaboticabal, São Paulo State, Brazil (21º14'05'' S, 48º17'09'' W, 600 m asl). A randomized block design was used with five replications and four treatments, consisting of different soil uses (crops) in the sugarcane fallow period: soybean only, soybean/fallow/soybean, soybean/millet/soybean, and soybean/sunn hemp/soybean. After two soybean crops, the LVef chemical properties remained at intermediate to high levels; while those of the LVw, classified as intermediate to high in the beginning, increased to high levels. Thus, the different soil uses during the sugarcane fallow period allowed the maintenance of LVef fertility levels and the improvement of those of the LVw. Two soybean crops increased macroporosity in the 0.0-0.1 m layer of the LVef; reduced soil aggregates in the 0.0-0.1 and 0.1-0.2 m layers of both soils, and reduced aggregate stability in these two layers of the LVw. Planting pearl millet or sunn hemp between the two soybean growing seasons promoted the formation of larger soil aggregates in the surface layer (0.0-0.1 m) of the LVw.

Effect of ground covers and tillage between raspberry rows on selected soil physical and chemical parameters and crop response

1993 ◽  
Vol 73 (4) ◽  
pp. 481-488 ◽  
Author(s):  
B. J. Zebarth ◽  
S. Freyman ◽  
C. G. Kowalenko
Keyword(s):  
Perennial Ryegrass ◽  
White Clover ◽  
Cover Crops ◽  
General Pattern ◽  
Aggregate Stability ◽  
Rubus Idaeus ◽  
Perennial Grasses ◽  
Total N ◽  
Organic C ◽  
Wet Aggregate Stability

The use of inter-row ground covers has been suggested to reduce soil degradation in raspberry (Rubus idaeus L.) production. The effect after 6 yr of consistent inter-row management of ground covers or roto-tillage in raspberry on soil wet aggregate stability (WAS), bulk density, organic C and total N, and mineralizable nitrogen in the Fraser Valley of British Columbia was studied. Management treatments included no cover crop or cover crops of barley (Hordeum vulgare L.), sheep's fescue (Festuca ovina L.), perennial ryegrass (Lolium perenne L.), and white clover (Trifolium repens L.). A general pattern of perennial grasses > legume and barley > control was observed for soil WAS. Some quantitative and qualitative differences in the organic component of the soil profile to 30 cm were detected among management treatments. The differences were not statistically strong because the changes were small relative to the large pool present, but were relatively consistent overall. The white clover treatment tended to have more organic carbon, particularly in the subsurface, than the other treatments. The four treatments that included inter-row vegetation tended to have a greater amount of total and mineralizable N than the clean-tilled control. Crop vigour, as indicated by cane diameter, was reduced by the perennial grasses, but the inter-row management had only limited effects on berry yield. White clover appears to provide the best compromise between improving soil quality and minimizing competition with the berry crop. Key words: Wet aggregate stability, barley, sheep's fescue, perennial ryegrass, white clover

scholarly journals Temporal Changes in Wet Aggregate Stability

1992 ◽  
Vol 35 (2) ◽  
pp. 493-498 ◽  
Author(s):  
G. A. Lehrsch ◽  
P. M. Jolley
Keyword(s):  
Aggregate Stability ◽  
Temporal Changes ◽  
Wet Aggregate Stability

scholarly journals Optimal Buffer Allocation For Unpaced Balanced And Unbalanced Mean Processing Time

2012 ◽  
Author(s):  
Zalinda Othman ◽  
Shahrul Kamaruddin ◽  
Mohd. Shihabudin Ismail
Keyword(s):  
Key Words ◽  
Coefficient Of Variation ◽  
Production Line ◽  
Processing Time ◽  
Simulation Method ◽  
Buffer Allocation ◽  
Throughput Rate ◽  
Processing Times ◽  
The Mean

Artikel ini membincangkan peruntukan penampan optimum untuk talian pengeluaran unpaced yang pendek dan boleh diharap (tiada mesin rosak). Parameter utama yang mempengaruhi talian dalam kajian ini adalah min masa pemprosesan (μ) dan pekali variasinya (Cv). Lapan taburan min masa pemprosesan telah dikaji. Setiap taburan dipadankan dengan 15 konfigurasi peruntukan penampan. Kaedah simulasi digunakan bagi menganggar kadar keluaran talian untuk setiap kes. Keputusan kajian menunjukkan peruntukan penampan tertentu mempengaruhi kadar keluaran talian. Bagi talian yang boleh diharap dan min seimbang, peruntukan penampan yang optima adalah dengan mengagihkan bilangan penampan secara sama rata ke setiap slot penampan. Jika penampan tambahan diperlukan selepas agihan dilakukan, letakkan penampan tambahan tersebut pada slot penampan yang di tengah. Manakala bentuk peruntukan penampan yang baik bagi talian yang mempunyai min tidak seimbang (dengan anggapan setiap stesen mempunyai Cv tetap dan boleh diharap) ialah mengikut bentuk taburan min masa pemprosesan talian tersebut. Kata kunci: Talian pengeluaran unpaced, min tidak seimbang, peruntukan penampan optima, talian seimbang, talian pengeluaran unpaced boleh diharap This article discusses an optimal buffer allocation for short unpaced production line and it is assumed reliable (no machines breakdown). The main parameters that affect the line are mean processing time (μ) and its coefficient of variation (Cv). Eight different mean processing time distributions were studied. Each distribution was matched with 15 different buffer allocations. Simulation method was used to estimate the line throughput rate. The results showed that the allocation of buffers affect the throughput rate. For a reliable and balanced line, the optimum buffer allocation is by equally distributing the number of buffers to each buffer slot. In the case of an extra buffer is needed after equally distribution, it is placed at the center buffer slot. Meanwhile, the best buffer allocation shape for a line with unbalanced mean (with the assumption that each station is having fixed Cv and is reliable) follows the shape of the mean processing times of that line. Key words: Unpaced production line, unbalanced mean, optimal buffer allocation, balanced line, reliable unpaced production line

scholarly journals Do different arbuscular mycorrhizal fungi affect the formation and stability of soil aggregates?

2019 ◽  
Vol 43 ◽  
Author(s):  
Marisângela Viana Barbosa ◽  
Daniela de Fátima Pedroso ◽  
Nilton Curi ◽  
Marco Aurélio Carbone Carneiro
Keyword(s):  
Arbuscular Mycorrhizal Fungi ◽  
Mycorrhizal Fungi ◽  
Soil Aggregates ◽  
Aggregate Stability ◽  
Stability Index ◽  
Arbuscular Mycorrhizal ◽  
Soil Aggregate ◽  
Porous Space ◽  
Soil Aggregate Stability ◽  
The Mean

ABSTRACT Soil structure, which is defined by the arrangement of the particles and the porous space forming aggregates, is one of the most important properties of the soil. Among the biological factors that influence the formation and stabilization of soil aggregates, arbuscular mycorrhizal fungi (AMF) are distinguished due to extrarradicular hyphae and glomalin production. In this context, the objective of this study was to evaluate different AMF (Acaulospora colombiana, Acaulospora longula, Acaulospora morrowiae, Paraglomus occultum and Gigaspora margarita) associated with Urochloa brizantha (A. Rich.) Stapf on soil aggregate stability. The study was conducted in a completely randomized design, using an Oxisol and autoclaved sand 2:1 (v/v), with seven treatments: five AMF; and treatments with plants without inoculation and with only the soil, with 5 replicates. The experiment was conducted during 180 days and the following variables were evaluated: mycelium total length (TML); production of easily extractable glomalin-related soil protein (GRSP) in the soil and aggregate classes; stability of the dry and immersed in water aggregates through the mean geometric diameter (MGD) and the mean weighted diameter (MWD) of aggregates; and the soil aggregate stability index (ASI). It was observed that the inoculation favored soil aggregation, with a high incidence of A. colombiana, which presented the highest MGD, TML and GRSP production in the aggregates with Ø>2.0mm and for A. colombiana and A. morrowiae in the aggregates with Ø<0.105 mm, when compared to the treatment without inoculation. These results show that there is a distinction between the effects of different AMF on the formation and stability of soil aggregates.

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