## 6 Agrotechnical Factors
### Effect of Plant Density  
In addition, thyme plant density within a specific area is another factor influencing the essential oil composition of thyme. [PERSON] et al. [122] found that reducing plant density in _Thymbra spicata_ L. led to a decrease in total phenol and flavonoids. Optimal row spacing between 20 and 30 cm has been suggested for achieving the best morphological and biochemical plant parameters [122; 123]. Conversely, [PERSON] et al. [124] demonstrated that _Thymus linearis_ of the Himalayan thyme prefers narrower spacing and higher plant densities, resulting in increased yields of essential oil and improved quality.  
The composition of thyme essential oil is highly influenced by a variety of factors, as discussed previously and summarized in Table 2, showing the effect of different abiotic and biotic factors on essential oil composition of thyme species. Under the different mentioned factors, _Thymus vulgaris_ shows an increased rate of thymol in the essential oil, in case of increased salinity at 150 mM NaCl [125] and at 100 mM NaCl [126] using substrate that contain 100 gm\({}^{-2}\) of humic acid, using biofertilizers such as AMF [119] or PGPB [121], and in the case of increasing shade rate by using shade nets with a shade index of 40% [127]. However, thymol rate decreased in case of drought stress [102; 103]. In fact, in response to stress, plants may exhibit a resistance mechanism by partially closing their stomata, which restricts the absorption of a reduced amount of CO\({}_{2}\) by the plant, directing it primarily towards the synthesis of essential secondary metabolites crucial for preventing cellular oxidation [128].  
\begin{table}
\begin{tabular}{c c c c c c c c c c c c c c c c c} \hline \hline
**Factor** & **Reference** & **Reference** & **Type-type** & **Treatment** & **\(\mathbf{m_{10}^{-10}}\)** & **\(\mathbf{m_{20}^{-10}}\)** & **\(\mathbf{m_{30}^{-10}}\)** & **\(\mathbf{m_{40}^{-10}}\)** & **\(\mathbf{m_{50}^{-10}}\)** & **\(\mathbf{m_{60}^{-10}}\)** & **\(\mathbf{m_{70}^{-10}}\)** & **\(\mathbf{m_{80}^{-10}}\)** & **\(\mathbf{m_{90}^{-10}}\)** & **\(\mathbf{m_{10}^{-10}}\)** & **\(\mathbf{m_{10}^{-10}}\)** \\ \hline \multirow{4}{*}{**Double**} & \multirow{2}{*}{[20]} & \multirow{2}{*}{[20]} & \multirow{2}{*}{[20]} & Calus Computed & 1.70 & 2.20 & 3.00 & 7.70 & 1.40 & 1.50 & 14.23 & 1.20 & 1.80 & 1.00 & 13.20 & 13.20 & 7.20 \\ \cline{3-14}  & & & Calus Computed & 1.00 & 5.10 & 10.80 & 1.60 & 1.30 & 13.0 & 1.20 & 1.30 & 1.30 & 9.80 & 9.60 & 3.10 \\ \cline{3-14}  & & & Normal projection & 1.00 & 1.32 & & 9.52 & 1.34 & 1.96 & 11.33 & & 2.00 & & 51.99 & 3.80 & 2.57 \\ \cline{3-14}  & & & Single-length & 1.10 & 1.10 & & 11.79 & 1.19 & 2.08 & 12.66 & & 2.35 & & 41.46 & 4.77 & 2.71 \\ \hline \multirow{4}{*}{**Sult**} & \multirow{2}{*}{[20]} & \multirow{2}{*}{[20]} & \multirow{2}{*}{[20]} & Control & 12.09 & 6.67 & 12.67 & & 0.01 & 0.06 & 2.98 & 12.37 & 0.56 & 15.90 & 3.13 & 2.77 \\ \cline{3-14}  & & & 150 and MCI MCI & 4.15 & 6.06 & 7.33 & & 0.05 & 0.08 & 4.75 &  
A high variability has been noticed in the concentration of the other active compounds in the different factors mentioned in Table 2, which can illustrate how these factors collectively contribute to the complexity and variability of thyme oil. While, in general, biotic factors such as AMF or PGPB and the application of humic acid showed higher active compound rates, this can be an effective way to obtain a higher quality of essential oil in thyme.