RESPONSE OF TAGETES ERECTA L. TO COMPOST AND
FOLIAR APPLICATION OF SOME MICROELEMENTS
An experiment was carried out at National Research Centre Farm at Giza
during two successive seasons 1999 and 2000 to study the effect of two levels of
compost (0.0, 3.5 and 7.0 ton/fed.) or foliar application of microelements (Zn
and Mn) or their combinations on growth, yield and chemical constituents of
African marigold plant Tagetes erecta L. Compost levels significantly
increased the vegetative growth characters and yield including, plant height,
number of branching, fresh and dry weight of herb and flower. The photosynthetic
pigments (chlorophyll a, b) caroteniod, total carbohydrate and mineral (N, P, K,
Zn, Mn, and Fe) as well as oil percentage and yield of herb and flowers were
pronouncedly affected by compost. The highest increment induced with highest
level of compost. Appreciable effects of zinc or, and manganese were observed on
all the studies parameters. However,
the effect of the two elements together was superior to any of them in
single. The combined effect
of compost and (Zn+ Mn) surpassed all other treatments and producing the best
results. Compost and micronutrients increased the profitability (in terms of
economic value) compared to the control. The two levels of compost combined
with (Zn+ Mn) resulted the
highest net economic returns; which represented more than 215% of the control. Fourty three components were identified in the oil of Tagetes
erecta L., compromising about 79%-in average-from the oil. The oxygenated
compounds consisted more than double the percent of hydrocarbonic ones in herb or flowers oil, with little
differences between the treatments. The major constituents of African marigold
oil were tagetone (23.9 and 19.5% in herb and flowers oil, respectively),
followed by geranyl acetate and cyclohexanone.