ORNAMENTAL & FLOWERS

Effect of Humic Acid on Yield and Quality of Marigold (Calendula officinalis L.) - Abstract

To study the effect of humic acid on yield and yield components of marigold, a complete randomized experiment with five levels of humic acid treatments (0, 500, 1000, 2000, 4000 mg/l) with three replications and 15 experimental plots was carried out. Analysis of variance showed that the effect of humic acid treatments on number of leaves and flowers, dry weight and plant height was significantly at the one percent probability level. Mean comparisons revealed that treatment with 2000 mg/l humic acid had the most dry weight, plant height, leaves and flowers number.

Humic acid effects on plant height were best for 2000 mg/l (yielding 27,45 cm, compared to the control with 18,55 cm). The humic acid effect on the dry weight (applying 2000 mg/l) yielded 215.7 gram, compared to the control with 141.26 gram. The positive effect of humic acid improving the ability to absorb nutrients may be due to its effect on the dry plant biomass, which was confirmed as well.

In conclusion, the effect of humic acid on yield and yield components of marigold was positive.

(Results of the Study by Ehsan Mohammadipour et al)

Table 1- Effecht of humic acid on the measured traits of marigold (Calendula officinalis L.)

Treatments	Seedling height (cm)	Leaves number	Flowers number	Dry Weight (g)
H₁	18,55 c	30,67c	18,43 d	141,26 c
H2	22.61b	38.01b	23.59bc	175.66b
H₃	24.37ab	40.09b	25.33ab	187.70b
H₄	27,45a	46.00a	27.13a	215.07a
H₅	22.05b	37.44b	20.70cd	171.36b

Treatments

Seedling height (cm)

Leaves number

Flowers number

Dry Weight (g)

H₁

18,55 c

30,67c

18,43 d

141,26 c

22.61b

38.01b

23.59bc

175.66b

H₃

24.37ab

40.09b

25.33ab

187.70b

H₄

27,45a

46.00a

27.13a

215.07a

H₅

22.05b

37.44b

20.70cd

171.36b

H₁ control; H₂: 500 mgl¹ humic acid; H₃: 1000 mgl¹ humic acid; H₄: 2000 mgl¹ humic acid; H₅: 4000 mgl¹ humic acid In each columm, means with a common letter are significant based on the LSD test.