RESEARCH NOTE

Maataloustieteellinen Aikakauskirja
Vol. 59: 37—40, 1987

STUDIES ON PRODUCTION TECHNIQUES OF SOME HERB PLANTS

II Row spacing and cutting height of dill herb (Anethum graveolens L.)

HÄLYÄ, S.

Dept, of Horticulture, University of Helsinki,
SF-00710 HELSINKI, Finland

Abstract. A study was undertaken to determine the row spacing and cuttingheight of dill
to produce a good quality herb in terms of high proportion of leaves. The row spacings were
12.5 or 25 cm, and the herb was harvested to the stubbles of 7.5, II or 15 cm.

The greatest dry leaf yield, 8 kg/100 m 2, was achieved with the narrow row spacing and
lowest stubble. The proportion of leaves of the dry herb was highest (68 °/o) when cut to the
highest stubble. The difference in the yields between the cuttings of 7.5 and 15 cm was signifi-
cant, only. The relation between the dry and fresh yields (11 %) remained unaffected.

Index words: cutting, dill, herb yield, row spacing

Introduction

Many studies have been carried out to
determine the optimum plant density for hor-
ticultural crops, however, only few of those
are for herb plants. Plant density influences
the plant growth and yield. Generally, with
increasing plant density the dry matter con-
tent and mean plant and fruit size decreases.
At the same time the total yield increases (e.g.
Franz and Fritz 1978 and Garrabrants and
Craker 1986). Fleeger and Schröder (1958)
and Putievsky and Basker (1977), on the
other hand, found marjoram yield (Origanum
majorana L.) not respond to row spacing.

There is growing interest in the Nordic
countries to produce dill herb for drying in

addition to fresh use. Thick stems have caused
problems because they retard drying and
lenghten the drying time. Leaves, instead, will
dry in shorter period of time and might lose
color and volatile oils during the long drying
period. Good quality dill herb consists mainly
of leaves. A study was carried out at the Uni-
versity of Helsinki in purpose to produce
abundant and good quality dill yield in terms
of high proportion of leaves. The effect of row
spacing and cutting height of the herb was in-
vestigated.

Materials and methods

The row spacings were 12.5 and 25.0 cm
which are commonly used in mechanical dill

37

JOURNAL OF AGRICULTURAL SCIENCE IN FINLAND

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production. The crop was harvested at leaf
stage, before flower bud formation. The three
cutting heights were 7.5, 11.0 and 15.0 cm.
The lowest cutting was thepractical minimum
in mechanical harvesting and the highest one
supposed to leave largest proportion of stems
in the field.

Dill (’Dura’) was sown at the rate of 200 g/
100 m 2 on a humous loamy soil on June 2.
Compound fertilizer (0.8—0.8—1.6 kg NPK/
100 m 2) was broadcast before sowing dill,
weeds were controlled by linuron before
germination of dill, and the field was irrigated
during the dry periods.

Plant density, height of the crop stand and
diameter of stems (basal end of the cut herb)
were measured, fresh and dried herb yields
were weighed. The stems and leaves were
separated and weighed before and after
drying. The herb was freeze-dried as descri-
bed by Mäkinen et ai. (1986).

The field trials were set up using a split-plot
(4.5 m 2 each) design in quadruplicate. Statis-
tical analysis was done using the analysis of
variance and the means were separated by
Tukey’s and Student-Newman-Keuls’ tests
(Steel and Torrie 1980).

Results and discussion

The plants reached a height of 30 cm by the
harvest time on July 15. The row spacing did
not affect the height of the dill crop. There
were no significant differences in the number
of plants (1342—1446 plants/m2 ) per unit area
between the row spacings. The density was 90
plants/m at a row spacing of 12.5 and signi-
ficantly (p < 0.05) larger, 168 plants/m, at
a spacing of 25 cm.

The total fresh herb yields ranged from 80
to 138 kg/100 m 2 (Table 1). The relation of
the dry and fresh yields accounted for 9.9—

11.6 %, the total dry herb yield being 7.0—

16.7 kg/100 m 2. The proportion of the leaves
in the total herb ranged from 55.9—70.2 %.

The total dry yields were 13.1 and 9.9 kg/
100 m 2, and the separated leaf yields (dry) 7.8
and 6.1 kg/100 m 2 with the row spacings of

Table I. Total herb and leaf yields (fresh and dry) and
diameters of fresh stems in relation to cutting
height of dill (Tukey 0.05) (Helsinki 1986).

Stub- YIELDS (kg/100 m;

) DlA-
b!e METERFresh Dry „

.cm of stems
Total Leaves Total Leaves nmt

7.5 138.2 a 63.5 a 14.6 a B.la 2.8 a
11 106.5 b 56.4 a 11.5 b 7.lab 2.9 a
15 80.3 c 50.8 b 8.4 c 5.7 b 2.4 b

12.5 and 15 cm, respectively. The differences
were significant (p < 0.1) (Fig. 1). Franz
and Fritz (1978) and Garrabrants and
Craker (1986) have also reported on larger
yields of aromatic plants when grown with
narrow row spacings.

The yields were the larger the lower the crop
was cut, and inversely, proportion of the
leaves increased the higher the crop was cut.
The highest proportion of leaves, 68 %, was
in the herb which was cut at 15 cm. The
figures are presented in Table 1 and Figure 2.

The diameters of the fresh stems ranged
from 2.4 to 2.9 mm (Table 1). The figures
being lowest when cut to the stubble of 15 cm.
The difference was significant (p < 0.05).

Accordingly, cutting at 15 cm resulted in
significantly smaller fresh yields than those at
7.5 and 11 cm, but in the important dry leaf
yields the difference was significant only

Fig. I. Total herb (a) and leaf yields (b) (dry) of dill
grown at row spacings of 12.5 and 25 cm (Hel-
sinki 1985).

38



between the cuttings of 7.5 and 15 cm. The
largest proportion of leaves and thinnest
stems, however, support the cutting of dill
herb to a high stubble.

Postharvest handling, specifically therates
and costs of drying with different proportion
of stems and leaves, as well the effects of the
treatments in different crop stands warrant
further investigation to determine the most
profitable techniques for the production of dill
herb.

Acknowledgements. I wish to thank Leena Puukka and
Kirsti Pääkkönen for technical assistance. This work was
supported by the Ministry of Agriculture and Forestry
and the Tiura foundation.

References

Franz, Ch. & Fritz, 1978. Cultivation aspects of Gen-
liana lulea L. Acta Hort. 73: 307—314.

Garrabrants, N. L. & Cracer, L. E. 1986. Optimizing
field production of dill. Hort. Sci. 21 (3): 830.

Heeger, E. F. & Schröder, H. 1958. Einige Bemer-
kungen zu Fragen des Anbaus von Majorana horten-
sis Moench in Hinblick auf die Methodik pflanzenbau-
licher Versuche mil Arznei- und Gewiirzpflanzen. Phar-
mazie 13: 480—486.

Mäkinen, S., Hälvä, S., Pääkkönen, K., Huopalahti,
R., Hirvi, T., Ollila, P., Nykänen, I. & Nykänen, L.

1986. Maustekasvitutkimus SA 01/813, loppuraport-
ti. Sadon käsittely ja aistinvarainen laatu, pp 41—65.

Putievsky, E. & Basker, D. 1977. Experimental cultiva-
tion of marjoram, oregano and basil. J. Hort. Sci. 51:
181 188.

Steel, R. G. D. & Torrie, J. H. 1980. Principles and
procedures of statistics, a biometrical approach. 633
p. New York.

Ms received January 29, 1987

Fig. 2. Proportions of stems and leaves in dill herb
harvested to low (7.5 cm), middle (11 cm) and
high (15 cm) stubble (Helsinki 1985).

39



SELOSTUS

Eräiden maustekasvien viljelyteknisiä kokeita.
II Rivivälin ja leikkuukorkeuden vaikutus
tillisatoon

Häivä, S.
Helsingin yliopisto, puutarhatieteen laitos,
00710 Helsinki

Kiinnostus kuivattavan tillin (Anethum graveolensL.)
tuottamiseen on kasvanut viime vuosina. Yhtenä ongel-
mana kuivauksessa on kuitenkin ollut tillin paksut var-
ret, jotkakuivuvat hitaammin kuin lehdet janostavat si-
ten kustannuksia pidemmän kuivausajan takia. Hyvälaa-
tuisessa kuivatussa yrtissä tulisi lehtien osuuden olla mah-
dollisimman suuri. Yhtenäiset mausteiden laatukriteerit
Suomesta kuitenkin puuttuvat.

Vuonna 1986 selvitettiin Helsingin yliopiston puutar-

hatieteen laitoksella rivivälin ja leikkuukorkeuden vaiku-
tusta lehtitillin satoon. Rivivälit olivat 12.5 ja 25 cm. Sa-
to leikattiin 7.5, 11 ja 15 cm:n korkeudelta ja kuivattiin
pakkaskuivurilla. Suurin kuivattu lehtitillisato (8 kg/
100 m 2) saatiin viljeltäessä 12.5 cm:n rivivälillä ja kor-
jattaessa sato 7.5 cm sänkeen. Lehtien osuus kokonais-
sadosta oli suurin (68 %) silloin kun sato leikattiin 15 sent-
timetrin sänkeen.

40