## 2 Materials and Methods
### Experimental Design
#### 2.2.2 Experimental Program  
From January 2021 to January 2023, early monitoring of halophyte planting was carried out. The research objects suitable for this experiment were selected through a comprehensive evaluation. In mid-February, 2023, this experiment was carried out in the middle of Yizhou District. Three different types of halophytes were planted randomly. Five large sample plots of 20 m \(\times\) 20 m were set for each halophyte. In order to avoid the interaction of different salt solutions between large sample plots, a 5 m buffer zone was set between large sample plots. A 5 m \(\times\) 5 m small sample plot was set at five positions in the four corners and center of each large sample plot. When the spacing between plants is too small, it will affect the balance between the promotion and competition between plants. To provide plants with a better living space, through many experiments and comparisons, the optimal spacing between halophytes was finally determined to be 2 m [16]. Therefore, one plant was planted in the four corners and five positions in the center of each plot, and the spacing between plants was 2 m. In total, there were 15 large plots, 75 small plots, and 375 samples in this experiment. After three different types of halophytes were planted in the small sample plot, fresh water was used for drip irrigation. After all three different types of halophytes had grown normally for 30 days, salt stress treatment was carried out again. Through the investigation of different areas in the study area, the lowest salt concentration of groundwater in the study area was found to be 150 mmol\(\cdot\)L\({}^{-1}\), and the highest was 300 mmol\(\cdot\)L\({}^{-1}\), under natural conditions. In order to simulate the common salt concentration levels in this study area, we designed five salt solutions with different concentrations, namely, 150 mmol\(\cdot\)L\({}^{-1}\), 200 mmol\(\cdot\)L\({}^{-1}\), 250 mmol\(\cdot\)L\({}^{-1}\), and 300 mmol\(\cdot\)L\({}^{-1}\), with 0 mmol\(\cdot\)L\({}^{-1}\) as the control (Table 2). Irrigation was carried out using drip irrigation. Five plots of each halophyte were irrigated with the above five salt solutions with different concentrations, and the period of drip irrigation was once every 7 days. The experiment was completed in mid-August, 2023, and the indexes were determined.  
\begin{table}
\begin{tabular}{c c c c c c c c c c} \hline \hline \multirow{2}{*}{**Type**} & **Organic** & **Total** & **Total** & **Total** & **Available** & **Available** & **Available** & **Available** & **Electrical** & \multirow{2}{*}{**pH**} & **Salt** \\  & **Matter** & **Nitrogen** & **Phosphorus** & **Potassium** & **Nitrogen** & **Phosphorus** & **Potassium** & **Conductivity** & **Content** \\  & **(g\(\cdot\)kg\({}^{-1}\))** & **(g\(\cdot\)kg\({}^{-1}\))** & **(g\(\cdot\)kg\({}^{-1}\))** & **(g\(\cdot\)kg\({}^{-1}\))** & **(mg\(\cdot\)kg\({}^{-1}\))** & **(mg\(\cdot\)kg\({}^{-1}\))** & **(mg\(\cdot\)kg\({}^{-1}\))** & **(mg\(\cdot\)kg\({}^{-1}\))** & **(ms\(\cdot\)cm\({}^{-1}\))** & & **(g\(\cdot\)kg\({}^{-1}\))** \\ \hline \multirow{2}{*}{
\begin{tabular}{c} Desert \\ soil \\ \end{tabular} } & \multirow{2}{*}{\(1.17\pm 0.4\)} & \multirow{2}{*}{\(0.09\pm 0.03\)} & \multirow{2}{*}{\(0.30\pm 0.05\)} & \multirow{2}{*}{\(34.10\pm 7.7\)} & \multirow{2}{*}{\(31.10\pm 5.1\)} & \multirow{2}{*}{\(2.17\pm 0.6\)} & \multirow{2}{*}{\(61.30\pm 13.9\)} & \multirow{2}{*}{\(11.19\pm 4.4\)} & \multirow{2}{*}{\(7.78\pm 2.1\)} & \multirow{2}{*}{\(30.07\pm 6.3\)} \\ \hline \hline \end{tabular} Note: The data in the table are mean and standard deviation.  
\end{table}
Table 1: Specific profile of soils in the study area.