The effect of deicing reagents on soil properties of the roadside lawns in Novosibirsk

Abstract

The aim of the study was to evaluate the effect of deicing reagents on soil properties of the roadside lawns in Novosibirsk. Location and time of the study. Roadside lawns and a public green square in the central part of the Novosibirsk city. Field and laboratory work was performed in late 2023–early 2024. Methods. Soil samples were analyzed according to the following methods: preparation of aqueous extract was done at the ratio of soil:solution of 1:5; determination of specific electrical conductivity and water pH was performed using the electrodes HI763123 and ESC-10603, respectively; the content of water-soluble sulfates was measured with precipitation of sulfate ions by barium chloride and determination of barium sulfate by turbidimetric method; water-soluble sodium was measured by atomic absorption spectrometer with flame atomization Kvant-2A; water-soluble chlorides were measured by ion-selective electrode Econix ECOM-Cl; and water-soluble phosphates were measured by molybdenum-blue spectrophotometric method. The statistical processing of the data was carried out using the principal components analyzis, as well as by variation, regression, correlation and variance analyses. Results. Application of deicing reagents (DR) altered most significantly the content of water-soluble sodium and chlorine in the urban soils of roadside lawns, the values of which reached as high as 443 mg Na/kg and 511 mg Cl/kg. Sulfate and phosphate concentrations depended on the DR application to a much lesser extent. The relationship of chlorine content with the sodium one was described by a simple linear regression equation with a coefficient of determination (R2) equal to 0,92: Cl = 1,503 × Na – 34,655, where Cl and Na concentrations are presented in mg/kg. A close positive relationship (R2 = 0,87) was also found between the sum of all four analyzed ions (SI) and specific electrical conductivity (EC), described by the linear equation SI = 0,0078 × EC – 0,985, where SI (sum of Na+, Cl–, SO42–, and PO42– ions) is represented in cmol(eq)/kg, and EC in μS/cm. Conclusions. In the urban soils of roadside lawns, as compared to the central part of the public square, a significant increase in the content of water-soluble sodium and chlorine was found: 7–24 times and 30–80 times, respectively. The increase in the concentration of these elements was associated with a 3,3-fold increase in the value of specific electrical conductivity (which characterizes the general level of soil salinization with easily soluble salts) and a change in the reaction from "slightly alkaline" to "moderately alkaline". Such significant changes in the chemical properties of the urban roadside soils are caused by the DR use, which may result in the suppression of growth and development of plants, especially tree species less adapted to salt pollution, eventually leading to their dying-off.