الفهرس 
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Abstract
As open field experiment was carried out at the Floriculture Nursery, Faculty of Agricultures, Assiut University during two continual seasons (2019/20 and 2020/21) to investigate the influence of some organic substances (humic acid and liquid compost) in aqueous solutions; each at the concentrations of 2000 and 4000 ppm, besides untreated control (only water) were applied as foliar sprays or as soil drenches on German chamomile growth, flower-heads yield, essential oil production and its main constituents, as well as some nutrient elements and active biochemical compounds content in leaves.
Chamomile seeds were sown in November 3rd 2019 and 2020, after treated with fungicide, on the experimental area in plots (experimental unites), each was 2x1 m including terrace divided into four rows with 20 cm distance and each row contained 20 hills at 10 cm distance (one feddan contained approximately 96000 plants).
This experiment was arranged in a split-plot design since the two application methods (foliar sprays and soil drenches) were distributed in the main-plots and the five treatments of organic substances in the sub-plots. Accordingly, the experiment was involved to treatments replicated four times.
Four doses of both organic substances were applied with the two application methods; the first was added after 45 days from sowing and followed by three doses at the same levels, two weeks intervals through growth season. The yield of flower-heads was harvested periodically at full opening stage; once or twice weekly depending on the acceleration of flowering that started from the first of February to the end of April.
The study presented the following principal concepts:
• Characteristics of vegetative and root growth.
• Floral parameters and flower-heads yield.
• Nutritional state of plant.
• Active biochemical components in leaves.
• Essential oil yield, its constituents and quality.
The obtained results could be summarized as follows:
• characteristics of vegetative and root growth
Application of humic acid and liquid compost treatments applied as a soil drench was more effective in stimulating the characteristics of vegetative and root growth (plant height, stem diameter, branch number, fresh and dry weights of shoots and root system per plant) than foliar sprays in most cases.
Each treatment of organic substances cleared enhancement effects on studied growth measurements, while they significantly decreased shoot: root (S/R) ratio compared to control.
Liquid compost at a concentration of 4000 ppm was the most pronounced treatment in stimulating the growth strongly as recorded significant increases in the growth characteristics and a great reduction in S/R ratio compared to the rest of organic substances treatment.
The interactive effects between application methods and organic substances indicated that liquid compost at 4000 ppm applied as a soil drench followed by foliar spray application showed a considerable improvement in plant growth resulted in the highest values of measurements, mostly, with significant increases compared to the other combinations.
• Floral parameters and flower-heads yield
Number of flower-heads per plant was markedly higher by a soil drench method than foliar spray application, but insignificant deference between them in flower diameter was noticed.
Both humic acid and liquid compost treatments increased number of flower-heads per plant and flower diameter with increasing their concentrations from 2000 to 4000 ppm showing significant increases compared to control.
Liquid compost at 4000 ppm was the most effective treatment in flowering stimulation and increasing flower diameter resulting in significant increase compared to the other treatments.
Results declared considerable variation in flower-heads production through flowering season since the collecting yield in March reached 78.5% of seasonal total yield, however, February and April recorded 5.5 and 16.0%, respectively.
All organic substances treatment significantly increased fresh and dry weight of flower-heads per plant and per feddan compared to control, meanwhile, liquid compost at 4000 ppm was exceeded as produced the heaviest yield significantly compared to the rest of organic materials treatment.
A direct relationship was found between the considerable increase in flower-heads production per feddan and their fresh and dry weights through flowering season that closely correlated with the harvest-time whereas the heaviest fresh and dry yields (58% of seasonal total yield) were induced in March, in contrast to this, the lightest yield occurred in April (13%), but February was intermediately (29%).
The interaction between organic substances and their application methods showed that the maximum yield of flower-heads per plant and per feddan was produced by liquid compost at 4000 ppm applied as a soil drench or as foliar sprays, insignificant difference between them was observed. Meanwhile, the best combination produced the heaviest fresh and dry yields of flower-heads were occurred by the same treatment with a soil drench method.
• Nutritional state of plant
The best treatments which stimulated and improved plant growth and development were closely associated with more balanced total uptake of nutrient elements (N, P, K, Ca and Mg). In contrast, the worst growth of control was correlated with the minimum values of such elements.
Chemical analysis of plant showed that a soil drench method increased nitrogen and phosphorus uptake, while foliar spray application increased potassium and calcium uptake, however, insignificant difference between both application methods was found in relation to magnesium uptake.
It was observed on antagonistic effect among K, Ca and Mg uptake, also a synergistic effect between Mg and P uptake. These findings were induced by liquid compost at 4000 ppm since the increase in Mg uptake caused decreases in K and Ca uptake and an increase in P uptake.
• Active biochemical components in leaves
Both application methods showed insignificant difference between them in relation to biosynthesis of photosynthetic pigments and total carbohydrates content, but leaf protein level was higher in soil drench method than in foliar application.
Humic acid at 2000 ppm was the most effective treatment is synthesis of chlorophyll “a”. Meanwhile liquid compost at 2000 or 4000 ppm was superior in increasing carotenoids content, but chlorophyll “b” was not significantly affected by any organic substance treatment compared to control.
Organic material treatments significantly increased leaf carbohydrates compared to control, while liquid compost at 4000 ppm was the most effective treatment in carbohydrates accumulation compared to the rest of treatments that closely associated with the highest carbohydrates: nitrogen (C/N) ratio in leaves.
Each treatment of organic substances cleared a considerable increase in leaf protein accumulation compared to control.
The interaction between organic substances and application methods indicated that liquid compost at 2000 or 4000 ppm applied as foliar sprays resulted in the highest C/N ratio that was in a direct coordination with a favorable and considerable effect on the increased flower-heads production. Furthermore, humic acid at 2000 ppm or liquid compost at 4000 ppm applied as a soil drench gave the highest leaf protein content.
• Essential oil yield, its constituents and quality
In general, whole organic substances addition improved essential oil characteristics (oil percentage, oil yield per plant and per feddan) compared to control.
It was noticed that the physiological activity of plant was associated with a close relationship with its metabolism processes reflected in raising the previous biochemical components which have a positive association with increasing essential oil yield per plant and per feddan. Since the best combination (liquid compost at 4000 ppm applied as a soil drench) cleared a considerable exceeded in essential oil yield (44 l/fed) but control showed inferior yield (14 l/fed.)
GLC analysis of the essential oil separated 30 components among them nine principal compounds representing 83.14-94.89% of total detected constituents with different treatments. Three main components are chamazulene (39.6-49.71%), bisabolone-oxide A (10.11-17.72%) and bisabolol-oxide B (8.88-13.20%) since the percentages in their ranges were markedly higher with foliar sprays than with a soil drench application.
Liquid compost at 4000 ppm declared the highest percentage of total three main component (73%) followed by humic acid at 2000 ppm (69%) that closely associated with improvement in oil chemical properties led to high-quality.
The interaction between organic substances and application methods showed that the highest seasonal yield of the three main components obtained by liquid compost at 4000 ppm applied as a soil drench followed by foliar application with the same treatment.
Recommendation
As evident from the results presented in this text, the combination of liquid compost at 4000 ppm applied as a soil drench proved to be the superior treatment which has high efficiency to produce German chamomile yield. This combined treatment was correlated with enhancement in vegetative and root characteristics which reflected on producing the maximum yield of flower-heads (3.3 and 1.2 ton/fed, fresh and dry, respectively) compared to control (1.9 and 0.67 ton/fed), as well as increased essential oil yield (44 l/fed) containing the optimum percentages of main components.
These findings were attributed to adequate absorption of the tested macronutrients and stimulation of physiological traits and metabolic processes in plant led to increases in biosynthesis of photosynthetic pigments, total carbohydrates and protein levels in leaf tissues.
So, it could be recommended to apply this treatment for organic German chamomile is cleanly, safety, health quality and free contaminated chemicals that is desirable in manufacturing of pharmaceutical, food industries and export as a promise medicinal crop.