Effect of lime (CaCO3) application on soil structural stability of a red earth

Soil Research ◽  
1998 ◽  
Vol 36 (1) ◽  
pp. 73 ◽  
Author(s):  
K. Y. Chan ◽  
D. P. Heenan
Keyword(s):  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Structural Stability ◽  
Wagga Wagga ◽  
Lime Treatment ◽  
Temporary Reduction ◽  
Red Earth ◽  
Lime Application ◽  
Soil Structural Stability ◽  
Cultivated Soils

Changes in soil structural stability as a result of lime application (1·5 t/ha) were monitored over 3 years in a red earth with contrasting initial pH, organic carbon, and structural stability conditions at Wagga Wagga, NSW. The lime was applied to the surface of the direct drilled-soil without any incorporation, but in the case of the cultivated soils, the lime was incorporated into the top 10 cm by scarifying. After liming, an initial temporary reduction in macroaggregate (>2 µm) stability was detected in the immediate surface (0-2·5 cm) of the direct-drilled soil where the highest increases in pH, losses in soil organic carbon, and increases in microbial biomass were also observed. The decrease in structural stability was attributed to lime-induced increases in biological decomposition and the resulting soil organic carbon losses. Subsequent samplings did not detect any difference in either macro- or micro- (<50 µm) aggregate stability of this soil as a result of lime treatment. In contrast, for the 2 cultivated soils which had lower initial structural stability and organic carbon levels, a decline in stability was not observed. Instead, significant increases in macroaggregate and microaggregate stability were detected 1·5 years after lime application. By the end of 3 years, macroaggregate stability of the limed cultivated soils approached that of the direct-drilled soil. The improvement in structural stability extended to 7·5 cm depth 3 years after lime application. Wet-sieving experiments using prolonged periods of shaking indicated enhanced stability of the water-stable aggregates of the limed cultivated soils but not the direct-drilled soils.

Organic carbon and associated soil properties of a red earth after 10 years of rotation under different stubble and tillage practices

Soil Research ◽  
1992 ◽  
Vol 30 (1) ◽  
pp. 71 ◽  
Author(s):  
KY Chan ◽  
WP Roberts ◽  
DP Heenan
Keyword(s):  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Management Practices ◽  
Management Practice ◽  
Wagga Wagga ◽  
Continuous Cropping ◽  
Carbon Level ◽  
Significant Difference ◽  
Red Earth ◽  
Stubble Burning

Differences in soil organic carbon level as a result of different tillage and stubble management practices under continuous cropping were studied in a 10 years old wheat/lupin rotation experiment on a red earth at Wagga Wagga, New South Wales. Stubble burning and tillage had a similar impact in reducing the total amounts of organic carbon in the top 0-2 m of soil. There was no significant difference between the conventional cultivation (3 cultivations) and reduced cultivation (1 cultivation) systems. A 31% difference in organic carbon in the top 0.1 m (2.42% v. 1.68%) was found between the extreme management practices, i.e. direct drill /stubble retained treatment and the conventional/stubble burnt treatment. These results highlight the important effect of management practice on soil organic carbon level under continuous cropping. Tillage had the additional effect of changing the distribution of organic carbon resulting in higher level in the 0.10-0.15 m layer. The reduction in organic carbon was accompanied by significant losses in total nitrogen, exchangeable calcium and magnesim, as well as reduction in biological activity and aggregate stability. Loss of 1% organic carbon resulted in a loss of 2-97 cmole(+) kg soil-1 of negative charge. However, C/N ratio remained constant at 12-1 under different tillage and stubble treatments. Finally, while stubble burning resulted in pH increase, tillage led to a significant reduction in soil pH (5.38 to 4.98) in the 0 - 0.05 m layer due to increased exchangeable A1 brought to the soil surface as a result of an inversion action.

Soil Structural Stability and Extracellular Polymeric Substances (EPS): transient binding agents affected by land-use.

2020 ◽  
Author(s):  
Marc Redmile-Gordon
Keyword(s):  
Land Use ◽  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Structural Stability ◽  
Extracellular Polymeric Substances ◽  
Aggregate Stability ◽  
Land Uses ◽  
Total Soil ◽  
Binding Agents ◽  
Soil Structural Stability

&lt;p&gt;Structural stability in agricultural soils is said to be maintained through production of &amp;#8216;biological binding agents&amp;#8217;, including temporary binding agents (fungi, roots), transient binding agents (EPS), and persistent binding agents (of less certain origin). We sampled soils from a long-term field trial, comprising previous grassland, arable and fallow land-uses in factorial combination with current land-uses of the same type: previous 3 land-uses &amp;#160;x current 3 land-uses = 9 treatments (Redmile-Gordon et al., 2020). Total soil organic carbon (SOC), EPS (including protein, and polysaccharide fractions; Redmile-Gordon et al., 2014), and mean weight diameter (MWD) of water stable aggregates (Le Bissonnais, 1996) were quantified.&lt;/p&gt;&lt;p&gt;Both EPS and MWD were correlated, and were both strongly influenced by current land-use (implemented 2.5 years before sampling), but not by previous land-use (implemented &gt; 50 years ago, terminated 2.5 years before sampling). While exopolysaccharides were significantly correlated to the soil&amp;#8217;s structural stability (p = 0.027), proteinaceous EPS were more closely related to the associated gains in soil aggregate stability (p = 0.002).&lt;/p&gt;&lt;p&gt;In contrast to EPS and soil stability, total soil organic carbon (SOC) was strongly influenced by previous land-use. Importantly, this indicates that any capacity for relatively stable organic matter to contribute to the soil&amp;#8217;s structural stability is overwhelmed by temporary/transient effects owed to current land-use. This is cause for optimism, as it seems the physical quality of soils might be improved by short-term application of managements that favour EPS production. This approach would represent a qualitative step beyond that of building total SOC, which can be difficult for land-managers to achieve. This study is the first to simultaneously assess the effects of land-use on proteinaceous and polysaccharide content of EPS, and link this to the structural stability of soils. Further understanding surrounding the ecology of EPS production, and disentangling the contributions of temporary (largely physical) vs. transient (biochemical) binding agents is hoped to contribute to the development of more efficient land-management strategies.&lt;/p&gt;&lt;p&gt;&amp;#160;&lt;/p&gt;&lt;p&gt;&lt;strong&gt;References:&lt;/strong&gt;&lt;/p&gt;&lt;p&gt;Le Bissonnais, Y., &lt;strong&gt;1996&lt;/strong&gt;. Aggregate stability and assessment of soil crustability and erodibility.&lt;br&gt;1. Theory and methodology. Eur. J. Soil Sci. 47, 425&amp;#8211;437.&lt;/p&gt;&lt;p&gt;Redmile-Gordon, M., Brookes, P.C., Evershed, R.P., Goulding, K.W.T., Hirsch, P.R., &lt;strong&gt;2014&lt;/strong&gt;. Measuring the soil-microbial interface: extraction of extracellular polymeric substances (EPS) from soil biofilms. Soil Biol. Biochem. 72, 163&amp;#8211;171.&lt;/p&gt;&lt;p&gt;Redmile-Gordon, M., Gregory, A.S., White, R.P., Watts, C.W. &lt;strong&gt;2020&lt;/strong&gt;. Soil organic carbon, extracellular polymeric substances (EPS), and soil structural stability as affected by previous and current land-use. Geoderma, 363. https://doi.org/10.1016/j.geoderma.2019.114143&lt;/p&gt;

Spatial variation in soil organic carbon and nitrogen at two field sites under crop and pasture rotations in southern New South Wales, Australia

Soil Research ◽  
2018 ◽  
Vol 56 (8) ◽  
pp. 780 ◽  
Author(s):  
Mark Conyers ◽  
Beverley Orchard ◽  
Susan Orgill ◽  
Albert Oates ◽  
Graeme Poile ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Spatial Variation ◽  
New South ◽  
New South Wales ◽  
Wagga Wagga ◽  
Soil Cores ◽  
South Wales ◽  
Sampling Protocols ◽  
The Mean

Estimating the likely variance in soil organic carbon (OC) at the scale of farm fields or smaller monitoring areas is necessary for developing sampling protocols that allow temporal change to be detected. Given the relatively low anticipated soil OC sequestration rates (&lt;0.5 Mg/ha.0.30 m/year) for dryland agriculture it is important that sampling strategies are designed to reduce any cumulative errors associated with measuring soil OC. The first purpose of this study was to evaluate the spatial variation in soil OC and nitrogen (N), in soil layers to 1.50 m depth at two monitoring sites (Wagga Wagga and Yerong Creek, 0.5 ha each) in southern New South Wales, Australia, where crop and pasture rotations are practiced. Four variogram models were tested (linear, spherical, Gaussian and exponential); however, no single model dominated across sites or depths for OC or N. At both sites, the range was smallest in surface soil, and on a scale suggesting that sowing rows (stubble) may dominate the pattern of spatial dependence, whereas the longer ranges appeared to be associated with horizon boundaries. The second purpose of the study was to obtain an estimate of the population mean with 1%, 5% and 10% levels of precision using the calculated variance. The number of soil cores required for a 1% precision in estimation of the mean soil OC or N was impractical at most depths (&gt;500 per ha). About 30 soil cores per composite sample to 1.50 m depth, each core being at least 10 m apart, would ensure at least an average of 10% precision in the estimation of the mean soil OC at these two sites, which represent the agriculture of the region.

Effect of sampling density on regional soil organic carbon estimation for cultivated soils

2012 ◽  
Vol 175 (5) ◽  
pp. 671-680 ◽  
Author(s):  
Weixia Sun ◽  
Yongcun Zhao ◽  
Biao Huang ◽  
Xuezheng Shi ◽  
Jeremy Landon Darilek ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Sampling Density ◽  
Cultivated Soils

Influence of organic matter, clay mineralogy, and pH on the effects of CROSS on soil structure is related to the zeta potential of the dispersed clay

Soil Research ◽  
2013 ◽  
Vol 51 (1) ◽  
pp. 34 ◽  
Author(s):  
Alla Marchuk ◽  
Pichu Rengasamy ◽  
Ann McNeill
Keyword(s):  
Organic Matter ◽  
Organic Carbon ◽  
Zeta Potential ◽  
Structural Stability ◽  
Soil Structure ◽  
Clay Mineralogy ◽  
Net Charge ◽  
Clay Dispersion ◽  
Soil Structural Stability ◽  
Negative Zeta Potential

The high proportion of adsorbed monovalent cations in soils in relation to divalent cations affects soil structural stability in salt-affected soils. Cationic effects on soil structure depend on the ionic strength of the soil solution. The relationships between CROSS (cation ratio of soil structural stability) and the threshold electrolyte concentration (TEC) required for the prevention of soil structural problems vary widely for individual soils even within a soil class, usually attributed to variations in clay mineralogy, organic matter, and pH. The objective of the present study was to test the hypothesis that clay dispersion influenced by CROSS values depends on the unique association of soil components, including clay and organic matter, in each soil affecting the net charge available for clay–water interactions. Experiments using four soils differing in clay mineralogy and organic carbon showed that clay dispersion at comparable CROSS values depended on the net charge (measured as negative zeta potential) of dispersed clays rather than the charge attributed to the clay mineralogy and/or organic matter. The effect of pH on clay dispersion was also dependent on its influence on the net charge. Treating the soils with NaOH dissolved the organic carbon and increased the pH, thereby increasing the negative zeta potential and, hence, clay dispersion. Treatment with calgon (sodium hexametaphosphate) did not dissolve organic carbon significantly or increase the pH. However, the attachment of hexametaphosphate with six charges on each molecule greatly increased the negative zeta potential and clay dispersion. A high correlation (R2 = 0.72) was obtained between the relative clay content and relative zeta potential of all soils with different treatments, confirming the hypothesis that clay dispersion due to adsorbed cations depends on the net charge available for clay–water interactions. The distinctive way in which clay minerals and organic matter are associated and the changes in soil chemistry affecting the net charge cause the CROSS–TEC relationship to be unique for each soil.

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