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.

scholarly journals Determination of soil specific surface area by water vapor adsorption: I Drying of soil samples

1987 ◽  
Vol 59 (2) ◽  
pp. 63-65
Author(s):  
Raina Niskanen ◽  
Väinö Mäntylahti
Keyword(s):  
Organic Carbon ◽  
Carbon Content ◽  
Mineral Soil ◽  
Clay Content ◽  
Fine Sand ◽  
Water Vapor Adsorption ◽  
Soil Samples ◽  
Organic Carbon Content ◽  
Clay Sample

Drying of three mineral soil samples (clay content 4—58 %, organic carbon content 1—5 %) equilibrated at 75.5 % relative humidity was studied. The soils were dried in an oven at +50°C, +70°C and + 105°C for 4 and 8 hours and in a desiccator over pure concentrated H2SO4 and P2O5. Drying over desiccants for 8 hours removed less water than drying at + 50°C. Drying over desiccants for 3—7 days was as efficient as drying at +70°C, for 14—24 days as efficient as 4 hours of drying at + 105°C. Eight hours of drying at + 105°C seemed to be too drastic, because it caused a greater weight loss in the clay sample of 5 % organic carbon content than did prolonged desiccant-drying. Drying at + 70°Cremoved as much water from fine sand which contained 4 % clay as prolonged desiccant-drying.

scholarly journals Can mud (silt and clay) concentration be used to predict soil organic carbon content within seagrass ecosystems?

2016 ◽  
Author(s):  
O. Serrano ◽  
P. S. Lavery ◽  
C. M. Duarte ◽  
G. A. Kendrick ◽  
A. Calafat ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Carbon Content ◽  
Clay Content ◽  
Cost Effective ◽  
Blue Carbon ◽  
Organic Carbon Content ◽  
Terrestrial Organic Matter ◽  
Seagrass Meadows ◽  
Clay Concentration ◽  
Seagrass Ecosystems

Abstract. The emerging field of blue carbon science is seeking cost-effective ways to estimate the organic carbon content of soils that are bound by coastal vegetated ecosystems. Organic carbon (Corg) content in terrestrial soils and marine sediments has been correlated with mud content (i.e. silt and clay), however, empirical tests of this theory are lacking for coastal vegetated ecosystems. Here, we compiled data (n = 1345) on the relationship between Corg and mud (i.e. silt and clay, particle sizes <63 μm) contents in seagrass ecosystems (79 cores) and adjacent bare sediments (21 cores) to address whether mud can be used to predict soil Corg content. We also combined these data with the δ13C signatures of the soil Corg to understand the sources of Corg stores. The results showed that mud is positively correlated with soil Corg content only when the contribution of seagrass-derived Corg to the sedimentary Corg pool is relatively low, such as in small and fast growing meadows of the genera Zostera, Halodule and Halophila, and in bare sediments adjacent to seagrass ecosystems. In large and long-living seagrass meadows of the genera Posidonia and Amphibolis there was a lack of, or poor relationship between mud and soil Corg content, related to a higher contribution of seagrass-derived Corg to the sedimentary Corg pool in these meadows. The relative high soil Corg contents with relatively low mud contents (i.e. mud-Corg saturation) together with significant allochthonous inputs of terrestrial organic matter could overall disrupt the correlation expected between soil Corg and mud contents. This study shows that mud (i.e. silt and clay content) is not a universal proxy for blue carbon content in seagrass ecosystems, and therefore should not be applied generally across all seagrass habitats. Mud content can only be used as a proxy to estimate soil Corg content for scaling up purposes when opportunistic and/or low biomass seagrass species (i.e. Zostera, Halodule and Halophila) are present (explaining 34 to 91% of variability), and in bare sediments (explaining 78% of the variability).

STUDIES WITH WASTE SULPHITE LIQUOR: II. WASTE SULPHITE LIQUOR AS A SOIL AGGREGATING AGENT

1959 ◽  
Vol 39 (2) ◽  
pp. 92-97 ◽  
Author(s):  
J. J. Doyle ◽  
A. A. MacLean
Keyword(s):  
Biological Activity ◽  
Organic Carbon ◽  
Carbon Content ◽  
Clay Content ◽  
Organic Carbon Content ◽  
Early Stages

Ammonium-base waste sulphite liquor (solids) (W.S.L.S.) was added to three soils and incubated for 7 weeks. Weekly measurements of organic carbon content and aggregation showed an increase in aggregation to a maximum at 3 weeks, followed by a decline and then by a second increase at 6 weeks. This increase and decline in aggregation paralleled very closely the corresponding biological activity as indicated by loss of organic carbon. Results suggest that decomposition of sugars is responsible for the⁁ development of aggregation in the early stages of incubation and that the ligninsulphonates may have an effect after further incubation.The aggregating effect of W.S.L.S. was compared with that of two synthetic conditioners HPAN and VAMA. The effect of all materials varied considerably with the clay content of the soil. Results indicate that W.S.L.S. is about 1/16 as effective as HPAN and about 1/36 as effective as VAMA.

scholarly journals A near infrared index to assess effects of soil texture and organic carbon content on soil water content

2018 ◽  
Vol 70 (1) ◽  
pp. 151-161 ◽  
Author(s):  
I. Soltani ◽  
Y. Fouad ◽  
D. Michot ◽  
P. Bréger ◽  
R. Dubois ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Carbon Content ◽  
Water Content ◽  
Soil Water ◽  
Soil Water Content ◽  
Soil Texture ◽  
Near Infrared ◽  
Organic Carbon Content

Biodegradation of 2,4-D herbicide as affected by Its adsorption-desorption behaviour and microbial activity of soils

Soil Research ◽  
1996 ◽  
Vol 34 (6) ◽  
pp. 1041 ◽  
Author(s):  
NS Bolan ◽  
S Baskaran
Keyword(s):  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Carbon Content ◽  
Microbial Activity ◽  
Clay Content ◽  
Freundlich Isotherm ◽  
Surface Concentration ◽  
Initial Increase ◽  
Organic Carbon Content ◽  
Adsorption Desorption

The adsorption-desorption behaviour and the degradation of an ionic herbicide (2,4-D) were examined using 10 soils from New Zealand that differed in their organic matter and clay content. Adsorption isotherms for 2,4-D were adequately described by the Freundlich isotherm and the values of the exponent N of the Freundlich isotherm were close to 1 (0.92-0.98), indicating that the adsorption isotherm tended to become linear. The extent of adsorption, as measured by the distribution coefficient (Kd), increased with an increase in soil organic carbon. The rate of desorption of 2,4-D followed first-order reaction kinetics with respect to surface concentration, and decreased with an increase in the organic carbon content of the soils. The rate of degradation of 2,4-D, as measured by the half-life (t1/2), decreased with an initial increase in soil organic carbon, which is attributed to the increase in adsorption. With increasing adsorption, the rate of desorption decreased, resulting in a low concentration of 2,4-D in the soil solution that is available for microbial degradation. When the organic carbon content was more than 12%, however, both the adsorption and rate of degradation increased. The enhanced degradation of 2,4-D at these levels of organic carbon may be related to the increased biological activity of the soil, as measured by substrate-induced respiration, and the decreased 2,4-D-induced inhibitory effect on microbial activity.

scholarly journals Effects of reduced and traditional tillage on soil properties and diversity of diatoms under winter wheat

2018 ◽  
Vol 32 (3) ◽  
pp. 403-409 ◽  
Author(s):  
Jadwiga Stanek-Tarkowska ◽  
Ewa A. Czyż ◽  
Anthony R. Dexter ◽  
Cezary Sławiński
Keyword(s):  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Winter Wheat ◽  
Soil Properties ◽  
Water Content ◽  
Bulk Density ◽  
Reduced Tillage ◽  
Research Station ◽  
Organic Carbon Content ◽  
Dispersible Clay

Abstract The aim of this study was to quantify soil properties, microbial biodiversity and crop yield under two tillage systems used for winter wheat production in monoculture. The study was conducted in the period 2013-2016, on a long-term field experiment on a silt loam at the Krasne Research Station near Rzeszów, Poland. Traditional tillage involved soil inversion whereas reduced tillage was a non-inversion system. The following soil properties: chemical (soil organic carbon, pH, available P, K, Mg), physical (soil bulk density, water content, stability in water), and biological (the diversity of diatoms) were measured on samples collected throughout the growing season and at harvest. Soil organic carbon content, water content and bulk density in the 0-5 and 5-10 cm layers were greater in reduced tillage than in traditional tillage. Under reduced tillage the amount of readily dispersible clay was reduced giving increased soil stability in water. Soil under reduced tillage had greater diversity of diatoms (139 taxa) than that under traditional tillage (102 taxa). Wheat yields were positively correlated with precipitation, soil water content and soil organic carbon, and negatively correlated with readily dispersible clay.

scholarly journals The use of in situ volumetric water content at field capacity to improve the prediction of soil water retention properties

2008 ◽  
Vol 88 (4) ◽  
pp. 533-541 ◽  
Author(s):  
Hassan Al Majou ◽  
Ary Bruand ◽  
Odile Duval
Keyword(s):  
Organic Carbon ◽  
Carbon Content ◽  
Water Content ◽  
Bulk Density ◽  
Water Retention ◽  
Field Capacity ◽  
Volumetric Water Content ◽  
Organic Carbon Content ◽  
Water Retention Properties

Most pedotransfer functions (PTF) developed over the past three decades to generate water retention characteristics use soil texture, bulk density and organic carbon content as predictors. Despite the high number of PTFs published, most being class- or continuous-PTFs, the accuracy of prediction remains limited. In this study, we compared the performance of different class- and continuous-PTFs developed with a regional database. Results showed that the use of in situ volumetric water content at field capacity as a predictor led to much better estimation of water retention properties compared with using predictors derived from the texture, or the organic carbon content and bulk density. This was true regardless of the complexity of the PTFs developed. Results also showed that the best prediction quality was achieved by using the in situ volumetric water content at field capacity after stratification by texture. Comparison of in situ volumetric water content at field capacity, with the water retained at different matric potentials as measured in the laboratory, showed field capacity to approximate 100 hPa, whatever the soil texture. Finally, the lack accuracy of PTFs that do not use the in situ volumetric water content at field capacity as predictor did not appear due to the test soils being unrepresentative of the soils used to develop the PTFs, but were instead related to poor correlations between the predictors used and the water retention properties. Key words: Pedotransfer functions, root mean square error, mean error of prediction, standard deviation of prediction, texture, bulk density, organic carbon content

Reactions of copper with soil affecting its availability to plants. I. Effect of soil type and time

Soil Research ◽  
1980 ◽  
Vol 18 (4) ◽  
pp. 447 ◽  
Author(s):  
RF Brennan ◽  
JW Gartrell ◽  
AD Robson
Keyword(s):  
Organic Carbon ◽  
Soil Properties ◽  
Carbon Content ◽  
Soil Type ◽  
Clay Content ◽  
Organic Carbon Content ◽  
The Difference ◽  
Western Australian

The effect of moist incubation on the availability of applied copper to wheat was examined in a range of Western Australian soils. Incubating soil with copper reduced its availability relative to freshly applied copper by up to 70%. The availability of copper to wheat plants decreased with increasing time of incubation up to 120 days. The extent of the decline in availability differed among soils. The difference did not appear to be specifically related to any one of the following soil properties-pH, organic carbon content, clay content, free sesquioxide content and levels of total and extractable copper.

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