# Hydrochemical Characteristics and Suitability Assessment of Groundwater Quality for Irrigation
## 3 Results and Discussion
### Hydrochemical Characteristics
The magnesium adsorption ratio (MAR) [37; 38] is a crucial index that determines irrigation water quality in terms of magnesium hazard. Higher values of magnesium pose a risk to agricultural yields after releasing sodium from the soil [39]. High magnesium values are a warning against using such water because long-term usage negatively influences the soil's chemical structure and ultimately affects the crop yield. At the measuring point at Nikinci, all analyzed samples were unsuitable (MAR \(>\) 50%), while at the measuring point at Sid, all analyzed samples were suitable for irrigation purpose (MAR \(<\) 50%). At the measuring point at Lacarak, 50% of samples were suitable and 50% were unsuitable for irrigation. These results suggest that water quality must be monitored due to potential harm to soil infiltration properties, growing plants, and irrigation equipment. Total hardness (TH) was calculated based on Equation (7) from Table 2. Average values were 138 at the measuring point at Sid, 203 at the measuring point at Lacarak, and 320 at the measuring point at Nikinci (Table 6). These results indicate that irrigation water is hard (TH 150-300 mg/L) to very hard (TH \(>\) 300 mg/L) and do not control corrosion of equipment. TH values around 100 mg/L provide corrosion control and are considered an acceptable limit [40]. Lower water hardness usually causes less loss of pipe mass and less pronounced corrosion. [PERSON]'s classification indicated good to excellent water quality throughout the observation period. USSL classification highlighted variations in salinity, indicating the \begin{table}
\begin{tabular}{c c c c c c c c c c c c c} \hline \hline  & \multicolumn{4}{c}{**Nikinci**} & \multicolumn{4}{c}{**Sid**} & \multicolumn{4}{c}{**Lacarak**} \\ \hline
**Irrigation** & & & & & & & & & & & & \\
**Water Quality** & **Min** & **Max** & **Average** & **SD** & **Min** & **Max** & **Average** & **SD** & **Min** & **Max** & **Average** & **SD** \\
**Indices** & & & & & & & & & & & & \\ \hline SSP & 6.54 & 17.83 & 11.91 & 3.59 & 6.31 & 13.24 & 8.90 & 2.31 & 4.77 & 31.87 & 24.17 & 8.89 \\ SAR & 0.25 & 0.83 & 0.58 & 0.18 & 0.26 & 0.58 & 0.37 & 0.11 & 0.21 & 1.82 & 1.28 & 0.51 \\ RSC & \(-\)3.37 & 2.01 & \(-\)0.07 & 1.51 & \(-\)2.43 & \(-\)0.51 & \(-\)1.41 & 0.62 & \(-\)0.73 & 2.52 & 1.59 & 0.99 \\ PI & 29.54 & 47.11 & 38.15 & 4.79 & 33.58 & 42.79 & 37.96 & 3.01 & 33.06 & 61.00 & 53.27 & 9.56 \\ KR & 0.05 & 0.20 & 0.13 & 0.04 & 0.06 & 0.15 & 0.09 & 0.03 & 0.05 & 0.47 & 0.33 & 0.14 \\ MAR & 52.63 & 60.51 & 58.41 & 2.27 & 26.66 & 38.92 & 33.13 & 4.56 & 21.62 & 61.98 & 48.03 & 11.08 \\ TH & 252 & 355 & 320 & 33 & 111 & 168 & 138 & 18 & 82 & 338 & 203 & 70 \\ \hline \hline \end{tabular}
\end{table} 
Table 6: Descriptive statistics of irrigation water quality indices at three monitoring locations. need for moderate leaching measures. FAO classification further supported the need for monitoring, with occasional shifts between classes. [PERSON]'s classification indicated good to excellent water quality throughout the observation period. At the measuring location at Nikinci, there was fluctuation in the water quality from Ia to Ib class of water for irrigation. At the measuring location at Sid, water quality was uniform through entire analyzed period and it belong to Ia class, while at the measuring point at Lacarak, both the Ia and II class of irrigation water were observed. The percentage representation of certain classes during the analyzed period according to the [PERSON]'s classification on all monitoring locations are shown in Figure 6.  
USSL classification highlighted variations in salinity, indicating the need for moderate leaching measures. Water samples at the measuring point at Nikinci were uniform throughout the entire analyzed period and belonged to the C3-S1 class. At the measuring point at Sid, water quality was in the C2-S1 class from 2011 to 2014. After that, until 2020, the remaining 60% of the analyzed samples belonged to the C3-S1 class.