## 2 Materials and Methods  
### Study Area  
The research was carried out in three administrative territorial units (AUTs) from the south of Galati (GL) County (Tulucesti (TUL) and Sendreni (SEN)) and north of Braila (BR) County (Vadeni (VAD)), southeast of Romania, in some agricultural territories from the Lower Danube Basin, which are near the Iron and Steel Plant (I.S.P.) industry (Figure 1) [1]. This area is geographically located in the Covurlui and Siret Plains and is characterized by quaternary loess and loessoid deposits of eolian origin, as well as fluviatile deposits. These deposits are the parent material for the prevalent soil types in this area, namely chemrozems and fluvisols.  
The sampling sites were located on arable lands, cultivated with the three main crops that have the highest favorability for the researched area, namely _Triticum vulgare Vill_. (wheat), _Zea mays_ L. (corn), and _Helianthus annuus_ L. (sunflower). The position of the collection sites is presented in Table 1.  
\begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Sample ID** & **Sampling Location** & **Longitude** & **Latitude** & **Altitude (m)** \\ \hline I-1a/1b & E of Sivita & 45\({}^{\circ}\)36\({}^{\prime}\)40.02\({}^{\prime\prime}\) & 28\({}^{\circ}\)03\({}^{\prime}\)53.05\({}^{\prime\prime}\) & 4 \\ I-2a/2b & V of Sivita, Tatarca Hill & 45\({}^{\circ}\)36\({}^{\prime}\)35.00\({}^{\prime\prime}\) & 28\({}^{\circ}\)02\({}^{\prime}\)19.00\({}^{\prime\prime}\) & 97 \\ I-3a/3b & NV of Tulucesti, right side of Tartuca Valley & 45\({}^{\circ}\)35\({}^{\prime}\)08.02\({}^{\prime\prime}\) & 28\({}^{\circ}\)01\({}^{\prime}\)35.95\({}^{\prime\prime}\) & 120 \\ I-4a/4b & NV of Tulucesti, left side of Tartuca Valley & 45\({}^{\circ}\)35\({}^{\prime}\)11.98\({}^{\prime\prime}\) & 28\({}^{\circ}\)01\({}^{\prime}\)56.00\({}^{\prime\prime}\) & 113 \\ I-5a/5b & NV of Ghiluan Sasa Forest & 45\({}^{\circ}\)37\({}^{\prime}\)29.01\({}^{\prime\prime}\) & 28\({}^{\circ}\)01\({}^{\prime\prime}\)08.01\({}^{\prime\prime}\) & 142 \\ I-6a/6b & Ghiluan Hill & 45\({}^{\circ}\)37\({}^{\prime}\)34.00\({}^{\prime\prime}\) & 28\({}^{\circ}\)01\({}^{\prime}\)42.00\({}^{\prime\prime}\) & 106 \\ II-1a/1b & on the right side of Malina Valley & 45\({}^{\circ}\)25\({}^{\prime}\)05.00\({}^{\prime\prime}\) & 27\({}^{\circ}\)56\({}^{\prime}\)36.00\({}^{\prime\prime}\) & 21 \\ II-2a/2b & between Serbesti Noi and Sendreni villages & 45\({}^{\circ}\)25\({}^{\prime}\)21.33\({}^{\prime\prime}\) & 27\({}^{\circ}\)53\({}^{\prime}\)37.05\({}^{\prime\prime}\) & 28 \\ II-1a/1b & V of Pietroiu & 45\({}^{\circ}\)19\({}^{\prime}\)19.91\({}^{\prime\prime}\) & 27\({}^{\circ}\)52\({}^{\prime}\)11.00\({}^{\prime\prime}\) & 7 \\ III-2a/2b & on the left side of Psalaru Valley & 45\({}^{\circ}\)23\({}^{\prime}\)30.02\({}^{\prime\prime}\) & 27\({}^{\circ}\)54\({}^{\prime}\)56.00\({}^{\prime\prime}\) & 5 \\ III-3a/3b & on the left side of Sendreni-Baldovinesti road & 45\({}^{\circ}\)23’38.62\({}^{\prime\prime}\) & 27\({}^{\circ}\)55\({}^{\prime}\)17.90\({}^{\prime\prime}\) & 5 \\ \hline \hline \end{tabular}
\end{table}
Table 1: The geographical position of soil sampling sites.  
Figure 1: Soil and crop collection sites in Tulucesti, Sendreni, and Vadeni, Galati–Braila region, SE Romania.