Required amounts of medium and fertilizer for potted culture of zucchini

doi:10.4236/as.2012.36099

Paper Menu >>

Journal Menu >>

Vol.3, No.6, 816-821 (2012) Agricultural Sciences

http://dx.doi.org/10.4236/as.2012.36099

Required amounts of medium and fertilizer for

potted culture of zucchini

Hiromi Ikeura*, Takahiko Tokuda, Yasuyoshi Hayata

School of Agriculture, Meiji University, Kanagawa, Japan; *Corresponding Author: [email protected]

Received 23 July 2012; revised 29 August 2012; accepted 13 September 2012

ABSTRACT

In Japan, zucchini culture has yet to get under-

way, and the current costs of zucchini can be

attributed to damage from soil-borne disease

and the unstable yields due to seasonal change

of female flowers. Eradication of these problems

will lead to st able supply and a conse quent price

reduction of zucchini fruits. We previously clari-

fied the efficacy of potted culture as a new cul-

ture method for zucchini, but potted culture can

be burdensome as the weak water and nutrient

retention capacity of the medium warrants its

regular replacement. To solve this problem, in

this study, we investigated the blend ratio for

mixing rice husk charcoal with peat and the

amount of fertilizer required for potted culture of

zucchini. Results revealed no significant differ-

ences in the length of the largest leaf, total

number of flowers, number of female flowers,

and the ratio of female flowers to total flowers

with different blend ratios of rice husk charcoal

to peat. However, the number of harvested fruits

increased with higher ratios of rice husk char-

coal to peat and was highest at 80:20. The length

of the largest leaf increased with increased

amount s of fertilizer, with the best response was

at 200 g. No significant differences were noted

between the ratio of female flowers to total

flowers in any treatments. In addition, the num-

ber of harvested fruits was highest with 160 g

and 200 g of fertilizer. Taken together, the opti-

mal blend ratio of rice husk charcoal to peat is

80:20, and the optimal amount of fertilizer with

this ratio is 160 g.

Keywords: Zucchini; Rice Husk Charco al; Peat;

Potted Culture; Fertilizer

1. INTRODUCTION

In Japan, large-scale zucchini culture has yet to get

underway, and the current costs of zucchini makes wide-

spread distribution prohibitive. The high cost of zucchini

can be attributed to damage from soil-borne disease and

the unstable yields due to seasonal change of female

flowers. Eradication of these problems will lead to stable

supply and a consequent price reduction of zucchini

fruits, which will open the door for zucchini business

prospects.

Generally, zucchini is produced open culture, but the

culture methods and cultivars are not established due to

difference environmental condition in some areas. Espe-

cially, planting density in zucchini culture is important to

prevent soil-borne disease. In fact, interstrain used in

zucchini culture was from 50 cm to 100 cm, and different

by producers or areas. There are many reports about

study to demonstrate optimum interstrain and cultivar in

zucchini culture [1].

We previously clarified the efficacy of potted culture

as a new culture method for zucchini [2]. However, pot-

ted culture can be burdensome as the weak water and

nutrient retention capacity of the medium warrants its

regular replacement. To solve this problem, we consid-

ered using rice husk charcoal and peat moss as a medium

as both are organic materials with a high cation exchange

capacity and are often used as a medium in soilless cul-

ture [3-9]. Rice husk charcoal and peat moss have been

studied for recycling and the subsequent reclamation of

solid and organic residues produced in agriculture, fam-

ing, forestry, and industry, and they are also being suc-

cessfully used as container media for ornamental plant

production [9,10]. In addition, these organic materials are

available for compost after use and are easily applied in

the field [10,11]. In particular, rice husk charcoal is made

from burning rice husks, which are generated from har-

vested rice, the principal food in Japan and Thailand [12].

In addition, rice husks are typically utilized as a medium

for ornamental crops (e.g., Chrysanthemum morifolium)

and as soil cover for protecting rice in nurseries by cov-

ering with oil paper. Such uses are common because rice

husk charcoal is affordable, has high cation exchange

and aeration properties, has good moisture retentiveness

due to its porosity, and mixes well with other substances

[4,13,14]. Moreover, Inden and Torres (2004) [14] re-

H. Ikeura et al. / Agricultural Sciences 3 (2012) 816-821 817

ported an increase in yield and total soluble solid content

in tomato when using coconut coir or perlite plus car-

bonized rice hulls as a growth substrate. Islam (2008) [15]

described focusing on good aeration and lightweight

properties and thereby found rise husk charcoal to be a

suitable medium for soilless culture. Peat moss, which

has high moisture and nutrient retentiveness as well as a

high buffering ability, is particularly utilized as a growth

medium for strawberry culture [5,16].

In this study, we investigated the effects of different

ratios of rice husk charcoal to peat moss as a medium as

well as the optimal amount of fertilizer required for zuc-

chini potted culture.

2. MATERIALS AND METHODS

2.1. Culture Conditions

Zucchini seeds “Diner” (Takii Co. Ltd., Kyoto, Japan)

were planted in a plastic tray containing propagation

medium (Coop Chemical Co. Ltd., Tokyo, Japan) and

vermiculite (Showa vermiculite Co. Ltd., Kanagawa,

Japan) (1:1). A hydroponic fertilizer (Otsuka house No. 1

and No. 2) diluted 2-fold in tap water (as a standard

concentration) was added for propagation. Interstrain and

interrow spaces after settled planting were 60 cm and 80

cm, respectively. Agrisheet was laid out in a greenhouse

as the pots should not have contact with regular soil.

Rice husk charcoal and peat were purchased from

Berry’s life Co. (Kagawa, Japan) and Nichias Co. (Tokyo,

Japan). Irrigation after settled planting was conducted at

3 L·pot−1 at 7 am daily.

2.2. Blend Ratio of Rice Husk Charcoal to

Peat

Culture was conducted in a greenhouse at Meiji Uni-

versity from July 6, 2008 to October 28, 2008. Zucchini

seeds were planted in 12-cm plastic pots (height 10 cm)

containing propagation medium, and seedlings were cul-

tured until developing 7 leaves. The plants were then

settled in 30.5-cm plastic pots (height 30.5 cm; medium

volume, 15 L; Kaneko Seed Co. Ltd., Gunma, Japan) on

July 28, 2008.

The following four blend ratios of rice husk charcoal

to peat were set: 80:20, 60:40, 40:60, and 20:80. Eighty

grams of delayed release fertilizer, Ecolong 424 (N:P:K

= 14:12:13, JCAM AGRI. Co., Ltd., Tokyo, Japan), and

210 g of compost (Fujimi group, Sizuoka, Japan) were

added, and the pH of each medium was adjusted to the

same level (pH 6.5) by adding 7 g of magnesium lime

(Aiko Sekkai Co., Tochigi, Japan) for 80:20 and 60:40

and 120 g of magnesium lime for 40:60 and 20:80. After

adding each medium, fertilizer, compost, and water were

mixed in a soil mixer and drained. All experiments were

replicated 3 times, with 10 plants per replicate.

2.3. Amount of Fertilizer

Culture was conducted from August 11, 2009 to De-

cember 15, 2009 under the same conditions with differ-

ent blend ratios of rice husk charcoal to peat. Plants were

settled in 30.5-cm plastic pots on August 29, 2009. The

following four amounts of fertilizer were set: 80 g, 120 g,

160 g, and 200 g. Based in the results of the above ex-

periments, the most appropriate ratio of medium was

mixed to a volume of 15 L. Other applied fertilizers were

210 g of compost and 7 g of magnesium lime. All ex-

periments were replicated 3 times, with 10 plants per

replicate.

Growth, Pollination, and Harvest

The length of the largest leaf, the total number of

flowers, and the number of female flowers were meas-

ured once every 7 days to establish the female flower to

total flower ratio. Pollination was conducted at 8 - 9 am,

and fruits were harvested at a size with a market value

(16 - 19 cm).

2.4. Statistical Analysis

Data are presented as mean and standard error values,

and statistical differences between treatments were tested

using the Tukey-Kramer test at P < 0.05.

3. RESULTS AND DISCUSSION

The effect of different ratios of rice husk charcoal to

peat on zucchini growth is shown in Table 1. There was

no significant difference in the length of the largest leaf,

total number of flowers, number of female flowers, or

the ratio of female flowers to the total number of flowers.

The number of harvested fruits per pot was 2.8 with

20:80, 2.7 with 40:60, 4.2 with 60:40, and 4.8 with 80:20,

respectively; an obvious increasing trend with increasing

rice husk charcoal (Figure 1). Endo et al. (2006) [16]

demonstrated the effects of root zone substrates consist-

ing of coir and peat mixture on the growth and yield of

strawberry and indicated that the marketable yield of

strawberries increased with decreasing peat ratios. Islam

(2008) [15] described that rice husk charcoal gave simi-

lar and/or better crop performance and yield of tomatoes

than rock wool under high-temperature stress conditions

(30˚C and 35˚C versus 25˚C), which showed that rice

husk charcoal can be used successfully as a growing me-

dium amendment for producing greenhouse tomato as

well as other nursery crops. Promchot and Boonprakob

(2007) [12] reported that rice husk charcoal was better

than agar for embryo culture of nectarines and that it

may be a substitute for vermiculite. Thus, rice husk

H. Ikeura et al. / Agricultural Sciences 3 (2012) 816-821

818

Table 1. Effect of different blend ratios of rice husk charcoal to peat on the growth of zucchini.

Days after planting (mean ± S.E.)

Treatment

15 days 22 days 29 days 36 days 43 days 50 days

20:80 71.20 ± 2.86ay 84.20 ± 4.29a 85.20 ± 1.87a 86.70 ± 2.26a 88.80 ± 4.87a 89.44 ± 5.03a

40:60 70.40 ± 4.38a 85.60 ± 3.50a 87.30 ± 2.91a 88.70 ± 2.79a 89.70 ± 2.41a 91.10 ± 3.14a

60:40 70.80 ± 2.66a 84.10 ± 4.56a 86.60 ± 5.06a 88.33 ± 4.80a 90.56 ± 3.21a 91.56 ± 3.00a

The length of

largest leaf (cm)

80:20 68.20 ± 4.76a 80.40 ± 5.62a 84.80 ± 5.55a 87.30 ± 4.81a 88.30 ± 4.90a 89.10 ± 5.03a

20:80 3.00 ± 0.94a 5.80 ± 0.79a 8.50 ± 0.71a 12.20 ± 1.75a 15.80 ± 1.87a 20.33 ± 1.87a

40:60 2.90 ± 0.57a 5.60 ± 0.70a 8.20 ± 0.63a 12.10 ± 1.20a 15.50 ± 1.18a 18.70 ± 1.19a

60:40 3.00 ± 1.05a 5.40 ± 1.11a 7.80 ± 2.10a 11.78 ± 1.72a 15.11 ± 2.37a 18.56 ± 2.35a

A number of female

flowers (flower)

80:20 3.60 ± 1.07a 6.20 ± 0.92a 8.90 ± 1.66a 13.00 ± 2.11a 16.50 ± 2.55a 19.90 ± 3.05a

20:80 20.90 ± 0.88a 28.40 ± 0.97a 34.00 ± 1.25a 42.70 ± 1.42a 50.60 ± 1.78a 57.89 ± 1.96a

40:60 20.10 ± 0.57a 27.30 ± 0.67a 33.80 ± 1.03a 42.30 ± 0.82a 50.10 ± 0.88a 57.40 ± 1.43a

60:40 21.00 ± 1.25a 29.00 ± 1.15a 35.50 ± 1.58a 43.00 ± 1.73a 51.44 ± 1.88a 57.22 ± 1.79a

Total number of

flowers (flower)

80:20 21.20 ± 1.03a 28.50 ± 5.62a 35.30 ± 3.09a 43.00 ± 3.02a 51.40 ± 2.95a 58.00 ± 3.97a

20:80 14.35 ± 1.08a 20.42 ± 0.82a 25.00 ± 0.57a 28.57 ± 1.23a 31.23 ± 1.05a 35.12 ± 0.95a

40:60 14.43 ± 1.00a 20.51 ± 1.04a 24.26 ± 0.61a 28.61 ± 1.45a 30.94 ± 1.35a 32.58 ± 0.83a

60:40 14.29 ± 0.85a 18.62 ± 0.96a 21.97 ± 1.33a 27.39 ± 0.99a 29.37 ± 1.26a 32.43 ± 1.32a

The ratio of female

flowers to the total

number of flowers

(%)

80:20 16.98 ± 1.04a 21.75 ± 0.16a 25.21 ± 0.54a 30.23 ± 0.70a 32.10 ± 0.86a 34.31 ± 0.77a

Days after planting (mean ± S.E.)

Treatment

57 day 64 day 71 day 78 day 85 day 92 day

20:80 89.44 ± 5.03a 89.75 ± 5.26a 89.75 ± 5.26a 89.75 ± 5.26a 89.75 ± 5.26a 89.75 ± 5.26a

40:60 91.60 ± 3.50a 91.60 ± 3.50a 91.60 ± 3.50a 91.60 ± 3.50a 91.22 ± 3.49a 91.22 ± 3.49a

60:40 91.50 ± 2.78a 91.50 ± 2.78a 91.43 ± 2.99a 91.43 ± 2.99a 91.43 ± 2.99a 91.43 ± 2.99a

The length of largest

leaf (cm)

80:20 89.10 ± 5.30a 89.67 ± 5.29a 89.67 ± 5.29a 89.67 ± 5.29a 89.67 ± 5.29a 89.67 ± 5.29a

20:80 22.89 ± 2.52a 25.50 ± 2.73a 27.00 ± 3.38a 28.88 ± 4.22a 30.50 ± 4.78a 31.38 ± 4.78a

40:60 20.70 ± 2.21a 22.70 ± 1.64a 24.10 ± 1.79a 26.10 ± 2.13a 28.78 ± 2.64a 29.00 ± 2.40a

60:40 20.78 ± 3.15a 22.88 ± 3.87a 24.86 ± 4.74a 26.43 ± 4.72a 28.43 ± 4.93a 30.29 ± 4.57a

A number of female

flowers (flower)

80:20 21.80 ± 2.94a 24.00 ± 3.20a 25.67 ± 3.46a 27.56 ± 3.54a 29.22 ± 4.38a 29.67 ± 3.61a

20:80 62.89 ± 2.62a 67.13 ± 2.36a 70.75 ± 2.49a 74.25 ± 4.65a 77.63 ± 5.66a 80.00 ± 6.61a

40:60 62.80 ± 1.55a 66.60 ± 1.65a 69.80 ± 2.20a 74.20 ± 3.33a 79.44 ± 2.96a 83.22 ± 2.82a

60:40 63.25 ± 2.12a 67.25 ± 2.25a 71.00 ± 2.00a 74.71 ± 2.06a 78.00 ± 2.52a 81.14 ± 2.54a

Total number of

flowers (flower)

80:20 61.90 ± 5.02a 66.67 ± 2.60a 69.89 ± 2.67a 73.67 ± 2.92a 77.22 ± 2.82a 80.44 ± 3.05a

20:80 36.40 ± 0.96a 37.99 ± 1.16a 38.16 ± 1.36a 38.89 ± 0.91a 39.29 ± 0.85a 39.22 ± 0.72a

40:60 32.96 ± 1.43a 34.08 ± 0.99a 34.53 ± 0.81a 35.18 ± 0.64a 36.22 ± 0.89a 34.85 ± 0.85a

60:40 32.85 ± 1.49a 34.01 ± 1.72a 35.01 ± 2.37a 35.37 ± 2.29a 36.45 ± 1.96a 37.32 ± 1.80a

The ratio of female

flowers to the total

number of flowers

(%)

80:20 35.22 ± 0.58a 36.00 ± 1.23a 36.72 ± 1.30a 37.41 ± 1.21a 37.84 ± 1.55a 36.88 ± 1.18a

The ratio of female flowers to the total number of flowers = a number of female/total number of flowers × 100; yDifferent letter indicate statistical differences

etween treatments were tested using the Turkey-Kramer test at P < 0.05 (n = 10). b

H. Ikeura et al. / Agricultural Sciences 3 (2012) 816-821 819

20%R 40%R 60%R 80%R

A number of harvest fruits per pot

Figure 1. Effect of different blend ratios of rice husk charcoal

to peat on the number of harvested zucchini fruits Vertical bars

represent one standard deviation of the mean. Different letters

indicate significant difference at the 5% level according to the

Tukey-Kramer test between treatments (n = 10).

charcoal has various effects on plant variety and growth

stages, but its most prominent effect is as a culture me-

dium. In addition, variety-specific responses should be

considered when giving recommendations for adding the

optimum proportion of organic material amendments to

horticultural potting substrate [17].

It is considered that the 80:20 medium drained well

because the amount of peat (which retains water) was

decreased and because zucchini is better suited to well-

drained soil. Oshio et al. (1981) [4] discussed that rice

husk charcoal has a porous structure which contributes to

aeration and water retention, which in turn enhances wa-

ter and nutrient (especially potassium and phosporous)

retention. These factors suggest that the number of har-

vested fruits increased because sufficient nutrients were

available as a result of the enhanced water and nutrient

retention in the medium.

Potted culture of zucchini is essential to be cheaper

cost of medium due to consisting mostly medium cost. In

Japan, rice is the staple crop, and rice husk charcoal is

abundant and affordable [14]. Therefore, the cost of rice

husk charcoal medium for potted culture will enable fea-

sible cultivation options for zucchini.

The effect of different amounts of applied fertilizer on

the growth of zucchini is shown in Ta b l e 2 . The length

of the largest leaf, total number of flowers, and the num-

ber of female flowers increased with higher amounts of

applied fertilizer and was highest at 200 g. This was

thought that a number of nude increased to have great

vigor of fruits growth with rise amount of applied fertil-

izer. There was no significant difference in the ratio of

female flowers to the total number of flowers in any

treatments. Temperature is an important external envi-

ronmental factor for female differentiation of Cucurbita-

ceae plants, the family to which zucchini belongs [18].

All experiments in the present study were conducted

under the same conditions in the same greenhouse to

ensure the same external variables. Thus it can be in-

ferred that the ratio of female flowers to the total number

of flowers does not fluctuate.

The effect of different amounts of applied fertilizer on

the number of harvested zucchini fruits is shown in Fig-

ure 2. The number of harvested fruits per pot was 4.6

with 80 g, 6.1 with 120 g, 8.7 with 160 g, and 8.9 with

200 g, and increased with increasing amounts of fertilizer

and was highest with 200 g. There was no significant

difference in the number of harvested fruits and the

growth of zucchini with 160 g and 200 g. It was assumed

that the nutrient uptake ability of the roots was limited

because the roots were restricted by the pot. For effective

tomato culture, Zuraiqi and Battilhi (1992) [19] recom-

mended four applications of nitrogen fertilizer per season

at a rate of 30 kg/ha at two-week intervals. In contrast,

Diez et al. (1997) [20] and Eghball and Power (1999) [21]

obtained no yield differences between crops grown with

compost and those grown with chemical fertilizer.

Evanylo et al. (2008) [22] reported that various treat-

ments with organic fertilizer and a commercial agricul-

tural fertilizer did not affect pumpkin or bell pepper

growth. Reiners and Riggs (1997) [23] demonstrated the

effect of nitrogen application and the variety of pumpkin

(Cucurbita pepo L.) marketable yield and found that

pumpkin yield was unaffected by 67, 112, and 157

kg·N·ha−1. On the other hand, Takemyou et al. (2002)

[24] reported that the growth of zucchini and harvested

fruits increased in line with increased amounts of applied

fertilizer and that 80 - 160 g medium from a 10 L volume

is suitable for potted culture of zucchini. In this study,

80 g 120 g160 g200 g

A number of harvest fruits per pot

Figure 2. Effect of different amounts of applied fertilizer on the

number of harvested zucchini fruits Vertical bars represent one

standard deviation of the mean. Different letters indicate sig-

nificant difference at the 5% level according to the Tukey-

ramer test between treatments (n = 10). K

H. Ikeura et al. / Agricultural Sciences 3 (2012) 816-821

820

Table 2. Effect of different amounts of applied fertilizer on the growth of zucchini.

Days after planting (mean ± S.E.)

Treatment

3 days 10 days 17 days 24 days 31 days 38 days 45 days 52 days

80 g 28.9 ± 0.5ay35.2 ± 1.1a 51.0 ± 1.5a61.9 ± 1.9a66.3 ± 2.0a73.0 ± 2.0a 75.8 ± 2.4a 78.0 ± 2.0a

120 g 30.4 ± 0.4a34.9 ± 0.5a 49.6 ± 1.1a62.0 ± 1.6ab68.7 ± 1.8a77.6 ± 2.7a 80.7 ± 2.4a 83.1 ± 2.2a

160 g 30.1 ± 0.6a35.2 ± 0.7a 52.2 ± 1.4a65.5 ± 1.3b75.0 ± 2.0a81.3 ± 1.9ab 83.4 ± 1.6ab 84.6 ± 1.6ab

The length of

largest leaf

(cm)

200 g 31.3 ± 1.0a34.7 ± 0.7a 50.0 ± 1.7a63.6 ± 3.0ab75.9 ± 4.0a82.2 ± 2.8b 84.4 ± 3.0b 85.3 ± 3.2b

80 g 6.8 ± 0.1a 11.4 ± 0.3a 17.4 ± 0.3a22.6 ± 0.3a30.0 ± 0.4a32.8 ± 0.4a 37.1 ± 0.5a 40.9 ± 0.7a

120 g 7.0 ± 0.0a 11.5 ± 0.2a 17.4 ± 0.2a23.0 ± 0.3a30.2 ± 0.4a33.9 ± 0.4a 37.8 ± 0.4a 41.0 ± 0.6a

160 g 6.9 ± 0.1a 11.7 ± 0.2a 17.5 ± 0.3a23.4 ± 0.2a31.0 ± 0.3a34.6 ± 0.3a 39.3 ± 0.3a 43.0 ± 0.4ab

A number of

female flowers

(flower)

200 g 6.8 ± 0.1a 11.3 ± 0.2a 17.2 ± 0.2a22.9 ± 0.5a30.7 ± 0.6a34.8 ± 0.6a 39.4 ± 0.7a 43.8 ± 0.7b

80 g 0.0 ± 0.0a 0.1 ± 0.1a 2.2 ± 0.2a 4.9 ± 0.3a 8.0 ± 0.5a 9.2 ± 0.8a 11.3 ± 0.8a 13.0 ± 1.0a

120 g 0.0 ± 0.0a 0.6 ± 0.2a 2.1 ± 0.2a 5.1 ± 0.2a 8.1 ± 0.2a 9.7 ± 0.2ab 11.7 ± 0.4ab 13.4 ± 0.6ab

160 g 0.0 ± 0.0a 0.3 ± 0.2a 2.4 ± 0.3a 5.4 ± 0.4b 8.8 ± 0.3a 10.6 ± 0.5b 12.6 ± 0.6b 14.6 ± 0.9b

Total number

of flowers

(flower)

200 g 0.0 ± 0.0a 0.1 ± 0.1a 1.6 ± 0.2b 4.6 ± 0.5a 7.9 ± 0.5a 9.4 ± 0.6a 11.7 ± 0.6ab 13.4 ± 0.9ab

80 g 0.0 ± 0.0a 1.0 ± 1.0a 12.6 ± 1.4a21.7 ± 1.3a26.8 ± 2.0a27.9 ± 2.1a 30.3 ± 1.8a 31.6 ± 2.0a

120 g 0.0 ± 0.0a 5.2 ± 1.4a 12.1 ± 1.1a22.2 ± 1.0a26.9 ± 0.9a28.7 ± 0.9a 31.0 ± 1.3a 32.8 ± 1.6a

160 g 0.0 ± 0.0a 2.6 ± 1.3a 13.7 ± 1.7a23.1 ± 1.6a28.4 ± 0.9a30.6 ± 1.4a 32.1 ± 1.6a 33.9 ± 1.9a

The ratio of

female flowers

to the total

number of

flowers (%) 200 g 0.0 ± 0.0a 0.8 ± 0.8a 9.2 ± 1.2a 19.9 ± 1.8a25.6 ± 1.3a26.8 ± 1.4a 29.5 ± 1.8a 30.5 ± 1.8a

Days after planting (mean ± S.E.)

Treatment

59 days 66 days 73 days 80 days 87 days 94 days 101 days 108 days

80 g 78.0 ± 2.0a78.0 ± 2.0a 78.0 ± 2.0a78.0 ± 2.0a78.0 ± 2.0a78.0 ± 2.0a 78.0 ± 2.0a 78.0 ± 2.0a

120 g 83.1 ± 2.2a83.1 ± 2.2a 83.1 ± 2.2a83.1 ± 2.2a83.1 ± 2.2a83.1 ± 2.2a 83.1 ± 2.2a 83.1 ± 2.2a

160 g 84.6 ± 1.6ab84.6 ± 1.6ab 84.6 ± 1.6ab84.6 ± 1.6ab84.6 ± 1.6ab84.6 ± 1.6ab 84.6 ± 1.6ab 84.6 ± 1.6ab

The length of

largest leaf

(cm)

200 g 85.3 ± 3.2b85.3 ± 3.2b 85.3 ± 3.2b85.3 ± 3.2b85.3 ± 3.2b85.3 ± 3.2b 85.3 ± 3.2b 85.3 ± 3.2b

80 g 42.8 ± 0.7a46.5 ± 0.8a 50.2 ± 0.8a52.5 ± 0.9a54.7 ± 1.0a56.2 ± 1.1a 57.5 ± 1.4a 59.0 ± 1.5a

120 g 43.6 ± 0.4a46.7 ± 0.6a 50.4 ± 0.7a52.9 ± 0.9a54.9 ± 1.0a56.3 ± 1.2a 58.8 ± 1.4a 59.9 ± 1.6a

160 g 45.4 ± 0.4ab49.6 ± 0.6ab 53.2 ± 0.7ab55.6 ± 0.8ab58.0 ± 1.0ab59.7 ± 1.1ab 61.3 ± 1.3ab 63.1 ± 1.6ab

A number of

female flowers

(flower)

200 g 45.8 ± 0.7b50.1 ± 0.7b 54.5 ± 0.8b57.2 ± 0.7b59.5 ± 0.8b61.8 ± 0.9b 63.7 ± 0.9b 66.1 ± 1.3b

80 g 14.0 ± 1.2a16.2 ± 1.3a 18.9 ± 1.1a20.9 ± 1.0a22.5 ± 1.1a23.8 ± 1.1a 25.3 ± 1.1a 26.4 ± 1.2a

120 g 14.8 ± 0.7ab16.7 ± 1.0ab 19.3 ± 1.0ab21.9 ± 0.9ab23.9 ± 0.7ab25.3 ± 0.6ab 26.6 ± 0.4ab 27.9 ± 0.5ab

160 g 15.8 ± 0.8b18.0 ± 1.2b 21.0 ± 1.0b23.3 ± 0.9b25.2 ± 0.9b26.8 ± 0.8ab 28.4 ± 0.7ab 29.9 ± 0.7ab

Total number

of flowers

(flower)

200 g 14.8 ± 1.0ab16.6 ± 1.2ab 20.2 ± 1.2ab22.9 ± 1.3ab24.7 ± 1.3ab26.9 ± 1.1b 28.6 ± 1.1b 30.8 ± 1.1b

80 g 32.5 ± 2.3a34.6 ± 2.3a 37.6 ± 2.0a39.8 ± 1.7a41.1 ± 1.7a42.3 ± 1.5a 44.0 ± 1.5a 44.7 ± 1.5a

120 g 34.0 ± 1.9a35.9 ± 2.4a 38.6 ± 2.5a41.7 ± 2.2a43.8 ± 2.0a45.3 ± 1.8a 45.6 ± 1.7a 46.9 ± 1.6a

160 g 34.9 ± 2.0a36.3 ± 2.4a 39.6 ± 2.1a42.0 ± 2.0a43.6 ± 2.0a45.1 ± 1.8a 46.5 ± 1.6a 47.6 ± 1.4a

The ratio of

female flowers

to the total

number of

flowers (%) 200 g 32.2 ± 1.9a33.0 ± 2.3a 37.0 ± 2.2a40.0 ± 2.3a41.5 ± 2.2a43.6 ± 2.0a 44.9 ± 1.7a 46.6 ± 1.6a

The ratio of female flowers to the total number of flowers = a number of female/total number of flowers × 100; yDifferent letter indicate statistical differences

etween treatments were tested using the Turkey-Kramer test at P < 0.05 (n = 10). b

H. Ikeura et al. / Agricultural Sciences 3 (2012) 816-821 821

the volume of medium was 15 L. Water retention and

nutrient capacity of rice husk charcoal differ from those

of peat, suggesting that the amount of applied fertilizer

in the present study is slightly higher than that of Take-

myou et al. (2002) [24].

Taken together, the optimum blend ratio of rice husk

charcoal to peat for potted culture of zucchini is 80:20,

and the optimum amount of fertilizer is 160 - 200 g. In

the future, we intend to examine the effect of timing of

side dressing application on zucchini yield.

REFERENCES

[1] Powell, C.A., Stoffella, P.J. and Paris, H.S. (1993) Plant

population influence on squash yield, sweetpotato white-

fly, squash silverleaf, and zucchini yellow mosaic, Hort-

Science, 28, 796-798.

[2] Ikeura, H., Tokuda, T. and Hayata, Y. (2012) Efficacy in

zucchini potted culture. Journal of the Japanese Society

of Agricu ltural Technolo gy, 19, 7-11.

[3] Beardsell, D.V., Nichols, D.G. and Jones, D.L. (1979)

Physical properties of nursery potting-mixtures. Scientia

Horticulturae, 11, 1-8.

doi:10.1016/0304-4238(79)90048-7

[4] Oshio, H., Nii, F. and Namioka, H. (1981) Characteristics

of kuntan (rice husk charcoal) asoa mediumof soilless

culture. Journal of the Japanese Society for Horticultural

Science, 50, 231-238. doi:10.2503/jjshs.50.231

[5] Yoshida, Y., Hanaoka, T. and Hidaka, K. (2002) Effect of

Composition of Nutrient Solution on Nutrient and Water

Uotake, Growth and Yield of “Nyoho” Strawberry Growth

with Peat Based Substrate. Horticultural Research, 1,

199-204. doi:10.2503/hrj.1.199

[6] Kato, H., Komori, A. and Miyake, H. (1996) Studies on

nutrient solution culture of roses by drainage bed using

rice husk charcoal as medium. Bulletin of Yamanashi

Prefectural Agriculture Resear ch Center, 7, 15-23.

[7] Sudhagar, R. and Sekar, K. (2009) Effect of coco peat

medium on growth and quality of poinsettia (Euphorbia

pulcherrima. Willd.). Asian Journal of Horticulture, 4,

52-56.

[8] Nazari, F., Farahmand, H., Khosh-Khui, M. and Salehi,

H. (2011) Effects of coir as a component of potting me-

dia on growth, flowering and physiological characteris-

tics of hyacinth (Hyacinthus orientalis L. cv. Sonbol-

e-Irani). International Journal of Agricultural and Food

Science, 1, 34-38.

[9] Vaughn, S., Deppe, N.A., Palmquist, D.E. and Berhow,

M.A. (2011) Extracted sweet corn tassels as a reneable

alternative to peat in greenhouse substrates. Industrial

Crops Production, 33, 514-517.

doi:10.1016/j.indcrop.2010.10.034

[10] Manios, T. (2004) The composting potential of different

organic solid wastes: Experience from the island of Crete.

Environment International, 29, 1079-1089.

doi:10.1016/S0160-4120(03)00119-3

[11] Bari, Q.H. and Koenig, A. (2001) Effect of air recircula-

tion and reuse on composting of organic solid waste. Re-

sources Conservation and Recycling, 33, 93-111.

doi:10.1016/S0921-3449(01)00076-3

[12] Promchot, S. and Boonprakob, U. (2007) Replacing agar

with vermiculite, coconut fiber and charcoal rice husk in

culture media for embryo rescue of immature nectarines

seeds. Thai Journal of Agricultural Science, 40, 167-173.

[13] Miao, Y., Horibe, K., Hoki, M. and Iwai, S. (1999) Uses

of rice husk charcoal for container culture. Bulliten Gra-

duate School of Bioresorce Mie University, 23, 31-36.

[14] Inden, H. and Torres, A. (2004) Comparison of four sub-

strates on the growth and quality of tomatoes. Acta Horo-

ticultureae, 644, 205-215.

[15] Islam, S. (2008) Evaluating performance of ecologically

sound organic substrates under different temperature re-

gimes. International Journal of Agriculture and Biology,

10, 297-300.

[16] Endo, M., Kiriiwa, Y. and Nukaya, A. (2006) Effects of

coir and peat ratios on growth, yield and water relations

of strawberries “akihime” grown in soilless culture,

Journal of the Japanese Society for Horticultural Science,

75, 344-349. doi:10.2503/jjshs.75.344

[17] Zaller, J.G. (2007) Vermicompost as a substitute for peat

in potting media: Effects on germination, biomass alloca-

tion, yields and fruits quality of three tomato varieties.

Scientia Horticulturae, 112, 191-199.

doi:10.1016/j.scienta.2006.12.023

[18] Wien, H.C., Stapleton, S.C., Maynard, D.N., Mc.Clurg, C.

and Riggs, D.I.M. (2004) Flowering, sex expression, and

fruiting of pumpkin (Cucurbita sp.) cultivars under vari-

ous temperatures in greenhouse and distant field trials.

HortScience, 39, 239-242.

[19] Zuraiqi, S. and Battikhi, A.M. (1992) The effect of Fre-

quency of Nitrogen Application on growth yield and

quality of tomato grown under plastic-house. Emir Jour-

nal of Agricultural Science, 4, 1-13.

[20] Diez, J.A., Roman, R., Caballero, R. and Caballero, A.

(1997) Nitrate leaching from soils under a maize-wheat-

maize sequence, two irrigation schedules and three types

of fertilizers, Agriculture, Ecosystems & Environment, 65,

189-199. doi:10.1016/S0167-8809(97)00045-5

[21] Eghball, B. and Power, J.F. (1999) Composted and non-

composted mature application to conventional and no-til-

lage systems: Corn yield and nitrogen uptake, Agronomy

Journal, 91, 819-825. doi:10.2134/agronj1999.915819x

[22] Evanylo, G., Sherony, C., Spargo, J., Starner, D., Brosius,

M. and Haering, K. (2008) Soil and water environmental

effects of fertilizer-, manure-, and compost-based fertility

practices in an organic vegetable cropping system. Agri-

culture, Ecosystems & Environment, 127, 50-58.

doi:10.1016/j.agee.2008.02.014

[23] Reiners, S. and Riggs, D.I.M. (1997) Plant spacing and

variety affect pumpkn yield and fruit size, but supple-

mental nitrogen does not. HortScience, 32, 1037-1039.

[24] Takemyou, T., Araki, T., Nagatani, H., Tamaki, M. and

Hayata, Y. (2002) Study on the potted culture of zucchini

(Cucurbita pepo L.). Bulletin of Hiroshima Prefectural

University, 13, 95-100.