Effect of potassium humate and nitrogen fertilizer on herb - Ozean ...

Journal <strong>of</strong> Applied Sciences 2(3), 2009
Said-Al Ahl (2005); Mauyo et al. (2008). The results in Table (1) show that plant growth is a function <strong>of</strong>
nutrients supply providing, there were clear significantly positive trend in increasing herb fresh yield by
spraying <strong>of</strong> <strong>potassium</strong> <strong>humate</strong>. Similar results were reported by Zaghloul et al. (2009) they indicated that
spraying Thuja orientalis plants with humic acid increased growth compared with control plants due to the
direct effect <strong>of</strong> humic acid on solubilization <strong>and</strong> transport <strong>of</strong> nutrients. These results are in accordance with
those obtained by Norman et al (2004) on marigolds <strong>and</strong> peppers <strong>and</strong> number <strong>of</strong> fruits <strong>of</strong> strawberries.
Chen <strong>and</strong> Avaid (1990) added that humic substances have a very pronounced influence on the growth <strong>of</strong>
plant roots <strong>and</strong> enhance root initiation <strong>and</strong> increased root growth which known root stimulator. Humic acid
improve growth <strong>of</strong> plant foliage <strong>and</strong> roots. Vaughan (1974) proposed that humic acids may primarily
increase root growth by increasing cell elongation or root cell membrane permeability, therefore increased
water uptake by increased plant roots, <strong>and</strong> added that it can produce root systems with increased branching
<strong>and</strong> number <strong>of</strong> fine roots, as a result potentially increase nutrients uptake by increase root surface area
(Rauthan <strong>and</strong> Schnitzer, 1981).
The interaction effect was significant in both cuts <strong>of</strong> both seasons. The highest values <strong>of</strong> plant fresh weight
were produced from the treatment irrigated every 3 days <strong>and</strong> sprayed with 1% <strong>potassium</strong>-<strong>humate</strong>, followed
by the treatment irrigated every 3 days <strong>and</strong> sprayed with 1% <strong>potassium</strong>-<strong>humate</strong> <strong>and</strong> fertilized with 1.2 g N
pot -1 at the two cuts in both seasons.
Essential oil production:
In both cuts in both seasons, irrigation intervals, <strong>potassium</strong>-<strong>humate</strong>, <strong>nitrogen</strong> application <strong>and</strong> their
interaction affected the percentage <strong>of</strong> essential oils in oregano (Table 1). The mean values <strong>of</strong> essential oils
due to irrigation intervals treatments showed that increasing the period <strong>of</strong> irrigation from 7 to 5 days
increased essential the percentage <strong>of</strong> oils. Increasing the period <strong>of</strong> irrigation from 3 to 5 days increased
percentage <strong>of</strong> essential oils. In other words, the irrigation <strong>of</strong> oregano plants every 5 days accelerated the
production <strong>of</strong> essential oils, while the severe stress conditions due to irrigated every 7 days decreased the
biosynthesis <strong>of</strong> the essential oils. Similar results were recorded by Singh et al. (1997) <strong>and</strong> Fatima et al.
(2000). The mean values <strong>of</strong> essential oils due to <strong>nitrogen</strong> application at 0.6 g N pot -1 <strong>and</strong> 1.2 g N pot -1
increased in both cuts <strong>of</strong> both seasons. Nitrogen fertilization might enhance the essential oil biosynthesis
processes through its direct or indirect role in plant metabolism resulting in more plant metabolites. These
finding are in agreement with those <strong>of</strong> Omer (1998) <strong>and</strong> Omer et al. (2008), who said that <strong>nitrogen</strong> <strong>fertilizer</strong>
was effective in increasing essential oil <strong>of</strong> Origanum syriacum <strong>and</strong> Ocimum americanum, respectively.
Essential oil percent in oregano fresh herb were significantly affected as a result <strong>of</strong> foliar application with
K-<strong>humate</strong> (Table 1). Zaghloul et al. (2009) reported that <strong>humate</strong> application lead to increase oil content in
Thuja orientalis. From the above mentioned results, it could be concluded that foliar application <strong>of</strong> K-
<strong>humate</strong> promoted growth <strong>and</strong> possessed the best oil percentage in oregano plant. Generally, the maximum
essential oil content was observed in the fresh herb <strong>of</strong> plants that irrigated every 5 days <strong>and</strong> sprayed with
1% K-<strong>humate</strong> <strong>and</strong> fertilized with 1.2 g N pot -1 in the two cuts.
The oil yield <strong>of</strong> oregano (ml plant -1 ) was affected by irrigation intervals, <strong>potassium</strong> <strong>humate</strong> <strong>and</strong>/or <strong>nitrogen</strong>
fertilization in both cuts <strong>of</strong> both seasons. Decreasing the period <strong>of</strong> irrigation from 7 to 5 days increased oil
yield in both cuts <strong>of</strong> both seasons. Increasing irrigation intervals from 3 to 5 days increased oil yield in both
cuts <strong>of</strong> both seasons. Moisture stress also decreased fresh herb yield, so there was a decrease in oil yield
with an increase in moisture stress. These findings agree with those <strong>of</strong> Singh <strong>and</strong> Ramesh (2000) <strong>and</strong>
Zehtab- Salmasi et al. (2001). They found that water deficit decreased the oil yield <strong>of</strong> rosemary
(Rosmarinus <strong>of</strong>ficinalis L.) <strong>and</strong> anise (Pimpinella anisum L.), respectively. Increasing <strong>nitrogen</strong> doses
resulted in gradual <strong>and</strong> significant increase in essential oil yield in both cuts <strong>of</strong> both seasons. The higher the
amount <strong>of</strong> the <strong>nitrogen</strong>, the higher was the oil yield. The response <strong>of</strong> volatile oil content to <strong>nitrogen</strong>
fertilization might be attributed to de novo meristemic cell metabolism in building dry matter with essential
oil production. These results agree with those <strong>of</strong> Omer (1998) <strong>and</strong> Omer et al. (2008), who found a positive
correlation between <strong>nitrogen</strong> <strong>fertilizer</strong> <strong>and</strong> essential oil content in herbage <strong>of</strong> Origanum syriacum <strong>and</strong>
Ocimum americanum, respectively in all cuttings. In addition, spraying oregano plants with K-<strong>humate</strong>
caused an increase in the essential oil yield (Table 1). Generally, the highest essential oil yield (ml plant -1 )
was obtained from plants irrigated every 5 days <strong>and</strong> fertilized with 1.2 g N pot -1 <strong>and</strong> sprayed at 1% K-
<strong>humate</strong> in both cuts <strong>of</strong> both seasons.
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