Effect of particle-size distribution, soil organic carbon content and organo-mineral aluminium complexes on acid phosphatases of seasonally flooded forest soils

2004 ◽  
Vol 41 (1) ◽  
pp. 69-72 ◽  
Author(s):  
Noemi Chacon ◽  
Nelda Dezzeo ◽  
Saul Flores
1985 ◽  
Vol 57 (3) ◽  
pp. 183-194
Author(s):  
Raina Niskanen ◽  
Antti Jaakkola

Analytical methods for testing soil fertility were compared in a material of 430 topsoil samples. The samples were analyzed for particle-size distribution, organic carbon content, pH(CaCl2), exchangeable Ca and Mg extracted with 1 M ammonium acetate (pH 7) and 1 M KCI, exchangeable K extracted with 1 M ammonium acetate (pH 7) and P extracted by the Bray 1 method. These soil properties were compared with the soil textural class and humus content class estimated visually, pH (H2O) and Ca, Mg, K and P extracted with acid ammonium acetate. The estimation of soil textural class was quite successful, but the content of organic matter was frequently underestimated. pH (H2O) and pH(CaCl2) were highly correlated and 95 % of the variation in pH (H2O) was explained by pH(CaCl2). Exchangeable Ca together with pH(CaCl2) explained about 90 % of the variation in Ca extracted with acid ammonium acetate. Exchangeable Mg explained about 70 % of the variation in Mg extracted with acid ammonium acetate. Exchangeable K explained 90 % of the variation in K extracted with acid ammonium acetate. The Bray 1 P and pH(CaCl2) explained 60 % of the variation in P extracted with acid ammonium acetate. pH(CaCl2), clay and organic carbon content explained 72—83 % of the variation in Ca. Mg, K and P were not highly dependent on pH, particle-size distribution and organic carbon content of soil.


2021 ◽  
Author(s):  
Dmitriy Moskovchenko ◽  
Roman Pozhitkov ◽  
Dzhamilya Ukarkhanova

Abstract The article presents the results of studying the composition of road dust in Tyumen, a large city in Western Siberia. On roads with different traffic intensities, 50 dust samples were taken, in which the particle size distribution, pH, and organic carbon content were determined. The content of 62 major and trace elements was studied using atomic emission spectrometry (AES-MS) и inductively coupled plasma spectrometry (ICP-MS). It was revealed that the dust has an alkaline reaction pH = 7.4 - 10.2, low organic carbon content (0.07 - 2.9%). The particle size distribution is dominated by particles PM = 100-250. The content of small particles (PM <2 and PM2-10) representing the greatest environmental hazard is minimal on roads with an average traffic intensity. Studies have shown that the main road dust pollutants in Tyumen are Ni, Sb, Cr, Zn, Co. The average geoaccumulation index (Igeo) values ​​are ranked as Ni (2.2) > Sb (1.5) > Cr (1.3) > Zn (0.4) > Co (0.4) > Cu (0.2). The contamination evaluation through enrichment factor (EF) calculation showed that road dust is highly enriched in Ni and significantly in Cr and Sb. More than 80% of Zn, Co, Cu and more than 90% of Ni, Sb, Cr come from anthropogenic sources. By the content of Ni and Cr, Tyumen surpasses all cities of the Earth where similar studies were carried out. The high Ni content is associated with the composition of local soils and roadways, increased content in vehicle exhaust gases, and abrasion of metal parts. Calculations of the total pollution indices (IPI and Zc) showed that the level of road dust pollution in most of Tyumen's territory is average, moderately hazardous.


2021 ◽  
Vol 24 ◽  
pp. e00367
Author(s):  
Patrick Filippi ◽  
Stephen R. Cattle ◽  
Matthew J. Pringle ◽  
Thomas F.A. Bishop

2021 ◽  
Author(s):  
Christoph Rosinger ◽  
Michael Bonkowski

AbstractFreeze–thaw (FT) events exert a great physiological stress on the soil microbial community and thus significantly impact soil biogeochemical processes. Studies often show ambiguous and contradicting results, because a multitude of environmental factors affect biogeochemical responses to FT. Thus, a better understanding of the factors driving and regulating microbial responses to FT events is required. Soil chronosequences allow more focused comparisons among soils with initially similar start conditions. We therefore exposed four soils with contrasting organic carbon contents and opposing soil age (i.e., years after restoration) from a postmining agricultural chronosequence to three consecutive FT events and evaluated soil biochgeoemical responses after thawing. The major microbial biomass carbon losses occurred after the first FT event, while microbial biomass N decreased more steadily with subsequent FT cycles. This led to an immediate and lasting decoupling of microbial biomass carbon:nitrogen stoichiometry. After the first FT event, basal respiration and the metabolic quotient (i.e., respiration per microbial biomass unit) were above pre-freezing values and thereafter decreased with subsequent FT cycles, demonstrating initially high dissimilatory carbon losses and less and less microbial metabolic activity with each iterative FT cycle. As a consequence, dissolved organic carbon and total dissolved nitrogen increased in soil solution after the first FT event, while a substantial part of the liberated nitrogen was likely lost through gaseous emissions. Overall, high-carbon soils were more vulnerable to microbial biomass losses than low-carbon soils. Surprisingly, soil age explained more variation in soil chemical and microbial responses than soil organic carbon content. Further studies are needed to dissect the factors associated with soil age and its influence on soil biochemical responses to FT events.


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