Searching for the Correlation Between the Activity of Urease and the Content of Nickel in the Soil Samples: The Role of Metal Speciation

Abstract

The purpose of this study was to verify the correlation between the activity of urease and the content of nickel in soil of temperate climate in relation to the land management. Moreover, the metal speciation was taken into account in order to search for the above-mentioned correlation. Arable lands, forested lands, and wastelands were analyzed. The basic soil parameters were determined such as pH, clay fraction content, and organic matter content. The speciation of nickel was studied by using BCR (Bureau Communitaire de Reference) sequential extraction procedure and flame atomic absorption spectrometry, while the urease activity was determined spectrophotometrically. The pseudo-total content of Ni in every sample was below 30 mg kg−1 of dry soil. The dominant form of nickel in the soil samples was the residual form. Although the urease activity varied slightly between the samples, the differences turned out to be statistically insignificant. However, the highly positive correlations between the urease activity, organic matter content, and the pseudo-total content of Ni were found and discussed. Moreover, the positive correlations between the urease activity and two geochemical forms of nickel, namely, active and residual form, were confirmed. The results of performed experiments prove that the method of land management does not significantly affect either the topsoil urease activity or the nickel distribution in the case of the extensive agriculture and forestry. However, the existence of at least two forms of the active soil urease was proposed. The first one―contained in the soil solution or loosely adsorbed on the soil particulates and the second one―strongly adsorbed onto the clay minerals. Also the complex role of the organic matter in protecting urease from external factors was presented. Finally, it was postulated that the nickel content in soil may be the indicator of the soil urease activity.

Multi-walled carbon nanotubes improve nitrogen use efficiency and nutritional quality inBrassica campestris

“…Soil urease activity was measured by phenol sodium hypochlorite colorimetry. 36 Soil sucrase activity was measured by the 3,5-dinitrosalicylic acid method according to Qin et al 37 Protease activity was measured as described by Boyce et al 38 Soil nitrate reductase activity was measured by phenol disulfonic acid colorimetry according to Moro et al 39 The details of the organic nutrient quantification experiments are provided in section S1 in the ESI †. All treatments were repeated three times, and three replicate samples were analyzed.…”

The impact of the mountain barrier on the spread of heavy metal pollution on the example of Gorce Mountains, Southern Poland

“…This is typical approach in case of monitoring works, as pseudo-total contents give an assessment of the maximum potentially soluble or mobile contents of metals (moreover, metals that are contaminants are usually not bound in silicates) (Relić et al, 2011 ). The extraction procedure was conducted based on US EPA standard and on our previous works (EPA, 1996 ; Miśkowiec & Olech, 2020 ; Miśkowiec et al, 2016 ). Approximately 1.5 g of each sample (dried previously to the constant mass in 105 °C), weighed to the nearest 0.0001 g, was digested with the mixture of the concentrated (65%) nitric acid and 8.8-M solution of hydrogen peroxide (solid to solution ratio 1:10) in a microwave oven.…”

“…The modified Bureau Communitaire de Reference (BCR) method (Rauret et al, 2000 ), successfully applied in our previous studies (Miśkowiec & Olech, 2020 ), was conducted for the so-called functional speciation analysis of the tested metals in soil. Four forms (FM) of metal binding in soil have been extracted.…”

Soil Microbial Community Composition and Diversity Analysis under Different Land Use Patterns in Taojia River Basin

“…PCR amplification system (50 µL) [29]: 2 × Taq master Mix 25 µL, Bar-PCR upstream and downstream primers (10 µmol/L) 1 µL, template DNA 1 µL, ddH2O to 50 µL. Each sample was amplified in triplicate with the 50 µL reaction under the following conditions [30]: 30 cycles of denaturation at 94 • C for 30 s, annealing at 55 • C for 30 s and extension at 72 • C for 30 s; with a final extension at 72 • C for 10 min. The fungal 18S rRNA gene variable region fragment was amplified by PCR, and the fungal primer sequence were NS1 and GCFung [30,31].…”