Impact of monovalent cations on soil structure. Part II. Results of two Swiss soils

Farahani, Elham; Emami, Hojat; Keller, Thomas

doi:10.1515/intag-2016-0092

Cited by 18 publications

(15 citation statements)

References 40 publications

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“…The sensitivity to clay dispersion caused by adding monovalent cations is higher in soils with clay contents >15% than in soils with lower clay content (Levy and Torrento, 1995), and SDC generally increases with increasing clay content (Levy and Torrento, 1995;Etana et al, 2009). Similarly, in Part II of our series of papers (Farahani et al, 2018), we have found that clay dispersion was higher in a clay soil than in a silty loam soil.…”

Section: Resultssupporting

confidence: 67%

“…Moreover, K ions within the diffuse double layer (DDL) probably increase DDL thickness, facilitating clay dispersion. In contrast, we found a smaller impact of K, compared to Na, on clay dispersion in Swiss soils in Part II of our study (Farahani et al, 2018). The dominant clay type in these soils was illite.…”

Section: Sdc (%)contrasting

confidence: 80%

“…Illite has an interlayer K deficiency and, therefore, some of the added K ions can be adsorbed between the clay layers of illite, i.e. illite can fix K. The role of clay mineralogy on K effects on soil structure will be discussed in detail in Part II of this series of papers (Farahani et al, 2018).…”

Section: Sdc (%)mentioning

confidence: 99%

“…We suggest that further studies are required to clarify the effect of K on K s at different EPP levels. In addition to K concentration, the effect of K on soil structure is also affected by clay mineralogy, and this will be discussed in Part II of this series of papers (Farahani et al, 2018). CONCLUSIONS 1.…”

Section: Sdc (%)mentioning

confidence: 99%

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Impact of monovalent cations on soil structure. Part I. Results of an Iranian soil

Farahani¹,

Emami²,

Keller³

et al. 2018

International Agrophysics

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A b s t r a c t. This study investigated the impact of monovalent cations on clay dispersion, aggregate stability, soil pore size distribution, and saturated hydraulic conductivity on agricultural soil in Iran. The soil was incubated with treatment solutions containing different concentrations (0-54.4 mmol l -1 ) of potassium and sodium cations. The treatment solutions included two levels of electrical conductivity (EC=3 or 6 dS m -1 ) and six K:Na ratios per electrical conductivity level. At both electrical conductivity levels, spontaneously dispersible clay increased with increasing K concentration, and with increasing K:Na ratio. A negative linear relationship between percentage of water-stable aggregates and spontaneously dispersible clay was observed. Clay dispersion generally reduced the mean pore size, presumably due to clogging of pores, resulting in increased water retention. At both electrical conductivity levels, hydraulic conductivity increased with increasing exchangeable potassium percentage at low exchangeable potassium percentage values, but decreased with further increases in exchangeable potassium percentage at higher exchangeable potassium percentage. This is in agreement with earlier studies, but seems in conflict with our data showing increasing spontaneously dispersible clay with increasing exchangeable potassium percentage. Our findings show that clay dispersion increased with increasing K concentration and increasing K:Na ratio, demonstrating that K can have negative impacts on soil structure.

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Section: Resultssupporting

confidence: 67%

Section: Sdc (%)contrasting

confidence: 80%

Section: Sdc (%)mentioning

confidence: 99%

Section: Sdc (%)mentioning

confidence: 99%

See 2 more Smart Citations

Impact of monovalent cations on soil structure. Part I. Results of an Iranian soil

Farahani¹,

Emami²,

Keller³

et al. 2018

International Agrophysics

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“…Relationship between SAR or CROSS and exchangeable cations may vary because many soil factors, including pH, affect exchange reactions, and hence, the dispersive charge. In spite of including K and Mg effects in the formula, the relationship between CROSS and clay dispersion or hydraulic conductivity, although stronger than SAR, has been found to vary with soil factors [47,[52][53][54]. It is becoming clearer that clay dispersion in relation to CROSS depends on the dispersive charge of a given soil.…”

Section: Validity Of Models Based On Irrigation Water Qualitymentioning

confidence: 99%

Irrigation Water Quality and Soil Structural Stability: A Perspective with Some New Insights

Rengasamy

2018

Agronomy

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Abstract:The sustainability of irrigated agriculture depends on the quality of irrigation water used. The electrolyte concentration (EC) of irrigation water may lead to the accumulation of salts in the root zone layers and affect the physiological functions of the crop by osmotic and ion toxicity effects. Further, the cationic and anionic composition of the water may alter the exchangeable cation composition of the soil as well as its pH. Because of the dominance of sodium salts in many sources of irrigation water, parameters related to sodium such as exchangeable sodium percentage (ESP) of soils and sodium adsorption ratio (SAR) of soil solutions have been commonly used to study the effects of sodium in irrigation water on soil structural stability. Quirk and Schofield's concept of 'threshold electrolyte concentration' (TEC) has shown the importance of electrolytes in preventing the effects of sodium on soil structure. Based on this concept, several models have been proposed to relate ESP or SAR with EC to predict the possible impacts of irrigation water on soil structural stability. However, many research reports indicate that this relationship varies with soils, and a given model is not suitable for all types of soils. Further, the effects of potassium and magnesium in the processes leading to clay dispersion are disregarded in these models. This essay analyses all the factors involved in the structural failure of soils with different cationic composition, identifies the defects in these TEC models, and re-defines TEC on the basis of new insights on dispersive and flocculating charges of soils. This review does not deal with EC effects on crops nor the role of contaminant ions not involved with soil structural stability.

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Early spring prescribed burning in mixedPinus halepensisMill. andPinus pinasterAit. stands reduced biological soil functionality in the short term

et al. 2020

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This study evaluates the effects of prescribed burnings on soil physico‐chemical and biological properties in the short term. This practice is still in the process of evaluation and its effect on Mediterranean pine forests is not understood completely. Prescribed burning was carried out in three plots of mixed Pinus halepensis and Pinus pinaster stands in Castilla‐La Mancha (Spain) while monitoring soil temperature. Vegetation coverage was measured and soil samples were taken before, immediately after and 1 year after burning. Texture, pH, soil electrical conductivity, cation exchange capacity, soil organic carbon, total nitrogen, available phosphorus, magnesium, calcium, potassium, basal soil respiration, microbial biomass carbon content and enzymatic activities of urease, dehydrogenase, phosphatase, and β‐glucosidase were evaluated by generalized linear models, and a principal component analysis was used to reveal the relations between variables. The vegetation cover was reduced by 85% after fire. Soil organic carbon increased immediately after burning to return to the previous values one year later. Phosphorous and cationic exchange capacity increased immediately after burning and remained high one year later, while electrical conductivity and sodium were significantly lower after a year. Basal soil respiration and glucosidase were not affected by prescribed burning. Microbial biomass carbon, urease, phosphatase, and dehydrogenase had significantly lowered one year after burning. Our results show that prescribed burning managed to decrease the vegetation cover of the understory while it also reduced soil biological functions in areas with poorly developed soil and a dry climate, where recovery periods can be longer than expected.

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Impact of monovalent cations on soil structure. Part II. Results of two Swiss soils

Cited by 18 publications

References 40 publications

Impact of monovalent cations on soil structure. Part I. Results of an Iranian soil

Impact of monovalent cations on soil structure. Part I. Results of an Iranian soil

Irrigation Water Quality and Soil Structural Stability: A Perspective with Some New Insights

Early spring prescribed burning in mixedPinus halepensisMill. andPinus pinasterAit. stands reduced biological soil functionality in the short term

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