DISTRIBUTION OF CARBON, NITROGEN, SULPHUR AND PHOSPHORUS IN PARTICLE-SIZE SEPARATES FROM GLEYSOLIC SOILS

1980 ◽  
Vol 60 (4) ◽  
pp. 783-786 ◽  
Author(s):  
A. A. HINDS ◽  
L. E. LOWE
Keyword(s):  
Particle Size ◽  
Soil Carbon ◽  
Organic P ◽  
Soil N ◽  
Dispersion Method ◽  
Ultrasonic Dispersion ◽  
Soil Material ◽  
Size Fractions ◽  
Particle Size Fractions ◽  
Fine Clay

Levels of C, N, S and organic P (Po) were determined in fine, medium and coarse clay- and silt-size separates obtained from five Gleysolic soils by an ultrasonic dispersion method. Contents of C, N, S and Po increased with decreasing particle size, with average C values increasing from 3.7% in the silt to 10.1% in fine clay fractions. The corresponding increases for N, S and Po were 0.26–1.17%, 0.037–0.178% and 0.043–0.172%, respectively. C/N and C/S ratios decreased with decreasing particle size, indicating a relative enrichment of N and S in the finer particle-size fractions. N/S showed little variation with particle size, while C/Po ratios were erratic. The three clay fractions accounted on average for 31.3% of the soil material, and for 39.1% of soil carbon. In contrast, the clay fractions together accounted on average for 52–59% of soil N, S and Po.

STUDIES ON THE DYNAMICS OF "RECENTLY" CLAY-FIXED NH4+ USING 15N

1980 ◽  
Vol 60 (1) ◽  
pp. 61-70 ◽  
Author(s):  
C. G. KOWALENKO ◽  
G. J. ROSS
Keyword(s):  
Particle Size ◽  
Clay Fraction ◽  
Extraction Methods ◽  
Size Fractions ◽  
Particle Size Fractions ◽  
Fine Clay ◽  
Tracer Methods ◽  
Field And Laboratory Conditions ◽  
The Relationship ◽  
Fast Release

The dynamics of fixation and release of NH4+ in soils were studied using tracer N under field and laboratory conditions. Field data showed that release of fixed NH4+ was relatively slow after an initial moderately fast release. Forty months of field weathering of Bainsville soil left 3.48 kg 15N/ha in the 75-cm profile of the 13.5 kg 15N/ha applied and most (76%) of this recovered 15N was fixed NH4+–N. The relative quantitative importance of recently fixed NH4+ in the various particle size fractions was not in the same order as the native fixed NH4+. The fine silt fraction (2–5 μm) fixed a larger amount (whole soil basis) than the fine clay fraction (< 0.2 μm). The coarse clay fraction (0.2–2 μm) fixed the most NH4+ added as well as being the fraction containing the most native fixed NH4+. Sand size fractions were shown to contain native fixed NH4+ and were capable of fixing a small amount of added NH4+. Measurements of recently fixed NH4+–N in various particle sizes covering four time intervals (up to 40 mo) of field weathering under fallow showed that the 0.2 to 2-μm fraction was quantitatively most important, the < 0.2-μm fraction most readily released recently fixed NH4+ and the 2 to 5-μm fraction was the most stable with respect to recently fixed NH4+. Plant growth affected the relative stability of the recently fixed NH4+ in the various particle size fractions. Laboratory studies of three Brookston soil samples revealed higher estimates of fixation of NH4+ by direct tracer methods than by indirect extraction methods. This discrepancy was assumed to have been caused by some exchange of added NH4+ with native fixed NH4+ and by some NH4+ being fixed on other sites. The relationship between mineralogical and related analyses to fixation of NH4+ was discussed.

scholarly journals Geochemical Fingerprint and Soil Carbon of Sandy Alfisols

Soil Systems ◽  
2019 ◽  
Vol 3 (3) ◽  
pp. 59 ◽  
Author(s):  
Jenifer L. Yost ◽  
Eric E. Roden ◽  
Alfred E. Hartemink
Keyword(s):  
Particle Size ◽  
Soil Carbon ◽  
Soil Depth ◽  
Soil Carbon Storage ◽  
Size Fractions ◽  
Particle Size Fractions ◽  
Weathering Indices ◽  
Geochemical Fingerprint ◽  
High Concentrations ◽  
Carbon Concentrations

Soil carbon storage is affected by particle-size fractions and Fe oxides. We assessed soil carbon concentrations in different particle-size fractions, determined the soil chemical composition of the soil, and weathering and mineralogy of sandy soils of the Wisconsin Central Sands, USA. Three land uses were studied (agriculture, forest, and prairie). The soils contained a minimum of 830 g sand kg−1 up to 190 cm soil depth. Approximately 46% of the sand was in the 250–500 μm fraction, and 5% was <125 μm. Soil carbon ranged from 5 to 13 g kg−1 in the topsoil, and decreased with depth. The <45 μm fraction tended to have high concentrations of carbon, ranging from 19 to 43 g kg−1 in the topsoil. Silicon content was over 191 g Si kg−1, and was lowest in the Bt horizons (191–224 g Si kg−1). Up to 29 g Fe kg−1 and 39 g Al kg−1 were present in the soil, and were highest in the Bt horizons. These soils were mostly quartz, and diopside was found throughout the soil profiles. Weathering indices, such as the Ruxton Ratio, showed that the C horizons were the least weathered and the Bt horizons were more weathered. We conclude that most of the carbon in these soils is held in the <45 μm fraction, and soil carbon and total Fe were lowest in the coarser size fractions.

Data synthesis of carbon distribution in particle size fractions of tropical soils: Implications for soil carbon storage potential in croplands

Geoderma ◽  
2018 ◽  
Vol 313 ◽  
pp. 41-51 ◽  
Author(s):  
Kenji Fujisaki ◽  
Lydie Chapuis-Lardy ◽  
Alain Albrecht ◽  
Tantely Razafimbelo ◽  
Jean-Luc Chotte ◽  
...  
Keyword(s):  
Particle Size ◽  
Soil Carbon ◽  
Carbon Storage ◽  
Tropical Soils ◽  
Soil Carbon Storage ◽  
Carbon Distribution ◽  
Data Synthesis ◽  
Size Fractions ◽  
Particle Size Fractions ◽  
Storage Potential

CHANGES IN NATURAL 15N ABUNDANCE OF SOILS ASSOCIATED WITH TILLAGE PRACTICES

1984 ◽  
Vol 64 (3) ◽  
pp. 345-354 ◽  
Author(s):  
F. SELLES ◽  
R. E. KARAMANOS ◽  
K. E. BOWREN
Keyword(s):  
Particle Size ◽  
Conventional Tillage ◽  
Soil N ◽  
Zero Tillage ◽  
Total N ◽  
Size Fractions ◽  
Particle Size Fractions ◽  
Tillage Practices ◽  
Total Soil ◽  
Total Soil N

The objective of this study was to determine changes in N dynamics in an Orthic Black Chernozem as a result of two tillage practices (conventional and zero tillage) using the variations in the natural 15N abundance of different soil-N fractions. After 14 yr, no significant differences in isotope composition of total soil-N between the two tillage practices could be found. However, changes were detected in the natural 15N abundance of the acid-hydrolyzable N and various organo-mineral size fractions which led to useful comparisons of the nature of N under the two systems. The N-content of the hydrolyzable-N fraction was similar at the 0- to 4- and 8- to 16-cm depth under both tillage practices, while it was significantly different at the 4- to 8-cm depth. The δa15N of this fraction was consistently higher than that of total soil N at all depths only under zero tillage. This was associated with the presence of more labile N compounds under zero tillage. No differences in the isotopic composition of the organomineral size fractions were found at the 0- to 4-cm depth. At the 4- to 8- and 8- to 16-cm depths, the δa15N values of the finer particle size fractions were higher under zero tillage than under conventional tillage. This indicates a more labile nature of the N associated with these size fractions under zero tillage. Key words: δa15N, conventional tillage, zero tillage, total N, acid-hydrolyzable fraction, particle size fractions

Possible role of aluminum in stabilizing organic matter in particle size fractions of Chernozemic and solonetizic soils

2002 ◽  
Vol 82 (2) ◽  
pp. 265-268 ◽  
Author(s):  
D. Curtin
Keyword(s):  
Particle Size ◽  
Organic Matter ◽  
Specific Surface ◽  
Clay Fraction ◽  
Organic Matter Content ◽  
Ultrasonic Dispersion ◽  
Organic C ◽  
Size Fractions ◽  
Particle Size Fractions ◽  
Organic Matter Stabilization

Although phyllosilicate clays, with their large surface areas, are often considered to play the leading role in stabilizing soil organic matter against microbial attack, several studies have suggested recently that oxides of Al and Fe may stabilize organic matter in some soils. The distribution of organic C and oxides in clay (< 0.2 and 0.2–2 mm) and silt fractions (2–5, 5–20, and 20–50 mm) of four Saskatchewan soils (organic C ranged from 21 to 46 g kg-1) was examined to differentiate the contributions of oxides and specific surface to organic matter retention. Carbon concentrations in the particle size fractions (separated following ultrasonic dispersion of the soils) tended to be highest in the fine silt and coarse clay fractions, not in the fine clay as would be expected if specific surface was the sole factor governing organic matter content. When data for the four soils were pooled there was a strong relationship between organic C (y) in the size fractions and Al (x) extracted by dithionite-citrate-bicarbonate [y = 33.9 x0,5 - 7.3; R2 = 0.90***], suggesting a role for A1 in determining the C storage capacity of the size fractions. The C: A1 ratio increased from an average of 12:1 in clay-sized material to 28:1 in coarse silt. Because it had less A1 per unit mass of C, organic matter in the silt separates may be more weakly bonded to mineral material than is clay-associated organic matter. This may imply that organic matter bound to silt is less stable, and thus susceptible to mineralization, than is organic matter residing in the clay fraction. Key words: Organic matter stabilization, particle size separates, extractable A1 and Fe

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