Iranian Medicinal Plants Society Journal of Medicinal plants and By-products 2322-1399 2 2 2013 09 01 Effect of Nutrition and Harvest Time on Growth and Essential Oil Content of Thymus vulgaris L. 143 151 108587 10.22092/jmpb.2013.108587 EN Bohloul Abbaszadeh Research Institute of Forests and Rangelands, Tehran, Iran Masoumeh Layegh Haghighi Young Researchers and Elites Club, North Tehran Branch, Islamic Azad University, Tehran, Iran Journal Article 2013 06 17 Thyme (<em>Thymus vulgaris</em> L.) is an important medicinal plant with highly valuable essential oils. In this study, effects of different fertilizer treatments and cuts on <em>Thymus vulgaris</em> L. was evaluated in 2008-2009. The research was conducted at Alborz Research Station, Research Institute of Forests and Rangelands, Karaj, Iran. The Experimental design was split plot in time in the form of a randomized complete block design with three replications. The main factor was nutritionin 16 levels consisting of different combinations of nitrogen (N), phosphorus (P), potassium (K) and manure (M): N<sub>0</sub>P<sub>0</sub>K<sub>0</sub>M<sub>0</sub>, N<sub>40</sub>P<sub>32</sub>K<sub>40</sub>M<sub>0</sub>, N<sub>80</sub>P<sub>64</sub>K<sub>80</sub>M<sub>0</sub>, N<sub>120</sub>P<sub>96</sub>K<sub>120</sub>M<sub>0</sub>, N<sub>160</sub>P<sub>128</sub>K<sub>160</sub>M<sub>0</sub>, N<sub>140</sub>P<sub>112</sub>K<sub>140</sub>M<sub>5</sub>, N<sub>120</sub>P<sub>96</sub>K<sub>120</sub>M<sub>10</sub>, N<sub>100</sub>P<sub>80</sub>K<sub>100</sub>M<sub>15</sub>, N<sub>80</sub>P<sub>64</sub>K<sub>80</sub>M<sub>20</sub>, N<sub>60</sub>P<sub>48</sub>K<sub>60</sub>M<sub>25</sub>, N<sub>40</sub>P<sub>32</sub>K<sub>40</sub>M<sub>30</sub>, N<sub>20</sub>P<sub>16</sub>K<sub>20</sub>M<sub>35</sub>, N<sub>0</sub>P<sub>0</sub>K<sub>0</sub>M<sub>40</sub>, N<sub>0</sub>P<sub>0</sub>K<sub>0</sub>M<sub>30</sub>, N<sub>0</sub>P<sub>0</sub>K<sub>0</sub>M<sub>20</sub> and N<sub>0</sub>P<sub>0</sub>K<sub>0</sub>M<sub>10</sub> (indices following the letters N, P and K are application rates in kg/ha, indices following the letter M are the application rates of manure in t/ha). The sub factor was harvest (cut) time (late May and early September). Results indicated that fertilizer, harvest date and their interactions significantly affected most of the traits. Mean comparison of the interactions indicated that treatments containing both chemical fertilizers and manure showed positive effects, although the most plant height was achieved with N<sub>160</sub>P<sub>128</sub>K<sub>160</sub>M<sub>0</sub> × 1<sup>st</sup> cut, in both years (32.5 cm in 2008 and 32.66 cm in 2009). Essential oil yield was the highest in 2008 in N<sub>120</sub>P<sub>96</sub>K<sub>120</sub>M<sub>10</sub> × 2<sup>nd</sup> cut (26.01 kg/ha), and in 2009 in N<sub>100</sub>P<sub>80</sub>K<sub>100</sub>M<sub>15</sub> × 1<sup>st</sup> cut (26.79 kg/ha). Generally, it can be concluded from the results that <em>T. vulgaris</em> responds well to fertilization, and selecting the best treatment depends on the objective of production. essential oil P-cymene Thyme Thymol γ-terpinene https://jmpb.areeo.ac.ir/article_108587_c1879532558deff977bf757aa1383488.pdf