Lead and zinc concentration in genetic horizons of Terra rossa soil at a local scale. How these concentrations differ?

Abstract

The goals of this study were to (i) determine the concentration of the Pb and Zn in Terra rossa soil, (ii) reveal its origin and (iii) establish how the concentration of these elements between genetic horizons differ. In a total of 128 soil samples collected from the genetic A and B horizon of 64 Terra Rossa soil profiles were analyzed for aqua regia soluble concentration of lead (Pb A and Pb B) and zinc (Zn A and Zn B) as well as soil properties: pH in KCl, CaCO 3 , soil organic carbon (SOC) and particle size distribution. The median value of Pb A , Pb B , Zn A , and Zn B were 41.6, 33.8, 106.1 and 103.8 mg/ kg, respectively. The principal component analyses have shown that the Pb and Zn contribute most to the variability of A horizon and have the same and natural origin-they are accumulated by geochemical weathering and soil-forming processes. Using non-parametric techniques (the two-sided Kolmogorov-Smirnov test (K-S) and a shift function (SF) we estimated that (i) the Pb A and Pb B distribution differ in spread and median and (ii) the Pb B distribution need to be progressively shifted, at the whole range starting from 2.8 mg/kg for the first decile; 7.2 mg/kg for the fifth decile (median) to 12.2 mg/kg for the ninth decile to match Pb A distribution. In the case of Zn, there is no evidence that the distribution of Zn A is in any way different than the distribution of Zn B. This implies that the Zn A and Zn B have a remarkably similar shape of their distribution functions and a noticeable slight shift with a value of 2.3 mg/kg at fifth decile. The analysis presented here illustrated why detailed statistical descriptions can help to better understand how and by how much lead and zinc distributions in Terra rossa genetic horizon differ.

Humus quality in Terrra rossa soils under olive groves with different soil management types

“…The studied soils are silty clay loams, except for one sample of soil under IOG that belongs to the silty clay texture class. Obtained results are typical for Terra rossa soils proven in many studies (Bellanca et al, 1996;Vingiani et al 2018;Miloš and Bensa, 2020;Miloš and Bensa, 2021).…”

“…Although typical Terra rossa soils formed "in situ" are non-calcareous (Škorić et al, 1985;Peh et al, 2003), a colluvial subtype of Terra rossa soil contains carbonates due to the presence of carbonate skelet (Bogunović et al, 2009). Some studies of Terra rossa of Middle Dalmatia (Miloš and Maleš, 1998;Miloš and Bensa, 2020) also reported a similar range of CaCO 3 content and attributed it to the process of colluviation. 2010) pointed out that the lower the SOC content in the original soil, the higher the increase after compost application.…”