## 3 Results
### Biofertilizers Improved Soil Physical and Chemical Traits under Salt Stress  
The physicochemical properties of soil after the experiment reported in Table 5 showed significant effects of the salt stress on the pH, EC, TOC, OM and available P. The pH values decreased after the experiment compared to the initial soil value (8.6). However, the application of compost under 120 mM salinity level decreased the pH to a lower value (7.94). Concerning EC, the application of the biofertilizers increased this parameter under non-stressed conditions, except that one recorded in the case of PGPR+AMF\({}_{2}\), which significantly decreased compared to the control. Under stressed conditions (120 and 240 mM), the EC values were significantly decreased. In the absence of salt stress, the TOC rate was reduced by half in the plants treated by PGPR+AMF\({}_{1}\) and PGPR+AMF\({}_{2}\) compared to the inoculated and non-amended control. The applied biofertilizers significantly enhanced the OM compared to the control independently to the salinity level. Moreover, the application of compost alone or in different combinations with AMF and/or PGPR bacteria enhanced the amount of OM in the soil. Concerning the available P content in the soil, the application of compost, AMF and PGPR bacteria alone or in different combinations enhanced the P content in the soil. The addition of compost, whether or not it was associated with AMF and/or PGPR, considerably increased the available P content under every salinity level. Figure 4: Effects of salt stress and biofertilizes on superoxide dismutase (SOD), catalase (CAT), peroxidase (POD) and polyphenol oxidase (PPO) activities in date palm vitrophants. Comp: compost; AMF\({}_{1}\): AMF consortium; AMF\({}_{3}\): AMF pure strain; PCFR plant growth promoting rhizobacteria. Data presented are means \(\pm\) standard deviations, n = 3. Bars followed by the same letters within the same salt stress level are not significantly different according to Student–Newman-Keuls test (\(p<0.05\)). \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline
**NaCl** & **Teatments** & **pH** & **EC (us - cm\({}^{-3}\))** & **TOC (\%)** & **OM (\%)** & **P\({}_{\rm{Gloss}}\) (ppm)** \\ \hline  & Control & 8.47 (0.08)  & 0.50 (0.12)  & 13.68 (1.06)  & 742.00 (12.00)  & 2.54 (0.10)  \\  & AMF\({}_{1}\) & 8.60 (0.02)  & 1.06 (0.06)  & 38.71 (2.03)  & 430.00 (5.00)  & 1.74 (0.02)  \\  & FGFR & 8.61 (0.02)  & 0.71 (0.16)  & 55.47 (2.60) [FOOTNOTE:]Footnote : footnotemark: [ENDFOOTNOTE] \\
0 mM & AMF\({}_{1}\)+Comp & 8.37 (0.01)  & 1.924 (0.10)  \\  & AMF\({}_{2}\)+Comp & 8.33 (0.04)  & 2.02 (0.09)  & 182.92 (8.34)  & 107.50 (24.50)  & 1.94 (0.10)  \\  & FGFR+AMF\({}_{1}\) & 8.69 (0.03)  & 0.26 (10.18)  & 61.03 (106)  & 318.50 (5.50)  & 0.43 (0.08)  \\  & FGFR+AMF\({}_{1}\)+Comp & 8.53 (0.04)  & 0.88 (0.10)  & 192.48 (11.54)  & 780.50 (1.50)  & 1.83 (0.13)  \\ \hline  & Control & 8.05 (0.08)  & 0.26 (0.10)  & 11.27 (1.09)  & 739.00 (14.00)  & 1.88 (0.18)  \\  & AMF\({}_{1}\) & 8.32 (0.05)  & 0.68 (0.10)  & 51.15 (1.94)  & 656.00 (0.00)  & 1.33 (0.20)  \\  & FGFR & 8.56 (0.03)  & 0.54 (0.12)  & 74.86 (1.60) [FOOTNOTE:]Footnote : footnotemark: [ENDFOOTNOTE] \\
120 mM & AMF\({}_{1}\)+Comp & 8.38 (0.05) [FOOTNOTE:]Footnote : footnotemark: [ENDFOOTNOTE \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline
**NaCl** & **Teatments** & **pH** & **EC (us - cm\({}^{-2}\))** & **TOC (\%)** & **OM (\%)** & **P\({}_{\text{O}ien}\) (ppm)** \\ \hline \hline PCPR+Comp & 8.37 (0.01) b  & 992.00 (6.00) f  & 1.43 (0.07) a  & 2.46 (0.12) a  & 261.34 (3.20) a  \\ PCPR+AMF\({}_{1}\) & 8.40 (0.01) b  & 1161.50 (2.50) c  & 0.52 (0.04) d  & 0.90 (0.06) d  & 50.48 (0.95) f  \\ PCPR+AMF\({}_{2}\) & 8.36 (0.02) b  & 1274.0 (10) a  & 0.56 (0.03) d  & 0.97 (0.05) d  & 49.92 (3.70) f  \\ PCPR+AMF\({}_{1}\)+Comp & 8.18 (0.02) d  & 891.00 (5.00) b  & 1.48 (0.14) a  & 2.55 (0.23) a  & 219.92 (1.29) c  \\ PCPR+AMF\({}_{2}\)+Comp & 8.18 (0.02) d  & 872.00 (7.00) b  & 1.51 (0.09) a  & 2.60 (1.06) a  & 208.88 (3.31) d  \\ \hline \hline \end{tabular}
\end{table}