PLANT ECOPHYSIOLOGY Plant Ecophysiology 2 (2010) 61-66

PLANT ECOPHYSIOLOGY

Effect of different planting beds on growth and development of strawberry in hydroponic and aquaponic cultivation systems

S. Afsharipoora*, H.R. Roostab

aIslamic Azad University, Jiroft Branch, Jiroft, Iran. bUniversity of Vali-e Asr, Rafsanjan, Iran.

Received on October 25, 2010; revised on December 24, 2010; accepted on January 10, 2011

Abstract Hydroponically integrated fish and plant production system (aquaponics) is a new production method that has received attention by growers and researchers recently. In order to investigate the effect of different plant substrates (per-lite/cocopeat ratios) on strawberry growth and development in hydroponic and aquaponic systems, a greenhouse experi-ment was carried out as a factorial trial with a completely randomized design in three replications. Results of statistical analysis showed that in hydroponic system, leaf, crown and root fresh weight, runner length, individual leaf weight, chlo-rophyll a and b content (in high cocopeat ratios), total chlorophyll and carotenoid content (in high cocopeat ratios), were significantly higher than aquaponic system. Increase of cocopeat to perlite ratio in hydroponic system caused a higher chlorophyll a and b content in leaves and this increase was accompanied with increase of plant growth. Results of this research revealed that most of the measured features were better in hydroponic system than in aquaponic system. In addi-tion, the perlite or cocopeat substrates individually were not appropriate for cultivation but their combination was found to be suitable as substrate for cultivation.

Keywords: Aquaponic; hydroponic; substrate; strawberry.

Introduction

Strawberry (Fragaria ananassa Duch.) is a crop which is cultivated in greenhouse in Iran. Therefore, developing new methods to increase its yield and quality can play an important role in improving the performance of strawberry green-houses. One of the modern soil-free cultivation methods is hydroponic method whose advantages such as control of crop nutrition, the capacity to increase planting density, decreasing diseases and pests and increasing the quantity and quality of the product have attracted many growers (Tuzel et al., 2001). In this method, organic and inorgan-ic beds are used for growing crops. The characte-ristics of various materials used as cultivation bed directly and indirectly affect the growth and pro-duction of the crop (Verdonk et al., 1982). Aera-

tion is an important factor which affects a crop productivity. Oxygen is a necessary element for cell activity so that if it is absent in rooting zone, the crop growth will be undermined because crop supplies the required energy for root growth and ion absorption by an oxygen-needing process, i.e. respiration. Aerobic conditions improve roots including capillary roots by uniform distribution of water and air in pores (Ronagi and Maftoon, 2003). If the pores contain equal amounts of wa-ter and air in a solid cultivation bed, the amount of oxygen will suffice for the normal growth and activity of roots (Bruce et al., 1980). By affecting the amount of pores, growth bed structure essen-tially influences the growth of the crops. In a study on strawberry cv. Camarosa planted in soil and perlite, it was found that the strawberries planted in perlite produced their highest yields in January and February which can be regarded as an early fruit with a high price as the economical *Corresponding authors email: siminafshar1388@gmail.com

62 S. Afsharipoor and H.R. Roosta / Plant Ecophysiology 2 (2010) 61-66

warranty and they had lower runners than the strawberries planted in soil (Hochmuth and Sweat, 1993). A study on productivity and quali-ty of strawberry on different cultivation beds with different ratios of perlite to zeolite showed that the best cultivation bed was the ratios of 1:1 and 1:3 of perlite to zeolite (Fotouhi Ghazvini et al., 2007). By comparing the beds of rock wool, per-lite + carbonized rice hull, cedar bark and coco-nut coir, Inden and Torres (2004) reported the highest yield of strawberry on the bed of perlite + carbonized rice hull. Among the beds of perlite, perlite + rice hull, perlite + carbonized rice hull and pure rice hull, Lee et al. (1999) reported the perlite followed by the mixture of perlite + car-bonized rice hull as the best beds for hydroponic planting of cucumber. In a study in Virgin Isl-ands in the U.S. in 1997 for the determination of appropriate amount of fish water waste as N source for guinea grass (Panicum maximum), the results showed that fish waste can provide water and organic nitrogen for forage production in dry seasons (Valencia and Flemming, 2000). An aq-uaponic system was constructed in Alberta, Can-ada which included four fishery tanks and four raft hydroponic tanks. The yield of strawberry and cucumber in this system was higher than the mean yield of commercial greenhouses where usual hydroponic systems are used (Savido et al., 2007).

Materials and Methods

The study was carried out in hydroponic

greenhouse of Agronomy Department, Valiasr University of Rafsanjan, Iran in autumn of 2009. Strawberry transplant roots cv. Paroos which had been procured from Kordestan, Iran, were washed out of soil by tap water. The disinfected plastofoam pots were filled with different ratios of perlite: cocopeat (only perlite, 75% perlite + 25% cocopeat, 50% perlite + 50% cocopeat, 25% perlite + 75% cocopeat, and only cocopeat). Six pots were filled with each planting bed and 3 transplants were planted in each pot and three pots of each planting bed were dissolved with hydroponic solution (1/2 concentration of Hoag-land solution) and three others were dissolved with aquaponic solution (procured from raft tanks). The pots were manually dissolved with the amount of 300 mL three times a day.

Aquaponic system (Fig. 1) was formed of a fish tank with the volume of 850 liters which consisted of 20 fish of carp, grass carp and silver carp type, each about 300 gr. These special types of fish were selected because carp is very resis-tant to temperature variations (especially high temperatures) and environment. Their tempera-ture need was 20-30C. Considering the available water temperature, these water-water fish species were nurtured. They were procured from fish pool. The water of fish tank was supplied by tap water with the adjusted temperature of 24C. The tank was made of galvanized metal and painted by pool-specific paint. An aquarium heater was mounted inside the tank and the tank was covered by a cloth net hatch to prevent fish from jumping out of water. The sewage of the tank consisted of

Fig. 1. Scheme of aquaponic system, University of Veli-e Asr, Rafsanjan, Iran.

Fish Tank

Purifier

Infiltration Tank

Degasifier Tank

Hydroponic Tank

S. Afsharipoor and H.R. Roosta / Plant Ecophysiology 2 (2010) 61-66 63 fish waste and uneaten feed. If this sewage enters hydroponic system, it will cover the roots, create an anaerobic environment and interrupt the ab-sorption of the elements which are carried out by active transportation and using oxygen. There-fore, they should be eliminated before entering into hydroponic system. A water pump was mounted under the tank to pump the water to cla-rifier. The capacity of clarifier was 60 l whose upper side was cylindrical and lower side was conical. The sewage was pumped to clarifier from the upper side and the solid materials depo-sited to the sides of cone at the bottom of cylind-er. These materials were eliminated by turning on the tap water once a day which was connected to the tip of the cone. By sole application of only clarifier, much of floating and undeposited solid materials would enter the hydroponic medium. So another system was needed to separate unde-posited and fine materials. A 30-litre filtration tank was mounted after clarifier inside which there was a plastic net with fine meshes. There-fore, water entered the filtration system due to the gravity and fine particles which had not been se-parated in the clarifier removed from water. This net was washed with high-pressure water twice a week. Then, the water entered a 30-litre degass-ing system to remove the harmful gasses which might have been produced during filtration. Af-terwards, it entered a 300-litre hydroponic tank and after the absorption of the required nutrition by plants, the water was passed to the fish tank from the hydroponic bed. The floated hydroponic tank was 20 cm in depth, 200 cm in length and 75 cm in width and was covered by a plastofoam plate with the diameter of 4 cm.

Nitrification process is carried out by bacteria nitrosomonas and nitrobacter which is normally created in the system and transforms fish tank water ammonia to nitrite and then, to nitrate. The conformity of nitrification and nutrient availabili-ty in aquaponic system is acquired at pH=7. As well, because when water is saturated by soluble oxygen, salinization has the highest efficiency, several air assists were used in tank. Fish were fed three times a day with 20 g fish food contain-ing 46% protein. To measure leaf, crown and root fresh weights, they were dissected and then weighed with a digital scale after separation. The length of runners was measured by a ruler. Plant pigments were measured by a spectrophotometer (80 UV/VIS Spectrometer PG Instruments Ltd).

The data gathered during the study were ana-lyzed and the effects of treatments were studied.

The means were compared on the basis of Dun-can Test by software SAS and the graphs were drawn by software Sigma Plot (V. 9).

Results

The results of analysis showed that leaf, root and crown fresh weights, runner length, single leaf weight, chlorophyll a and chlorophyll b (in high ratios of cocopeat), total chlorophyll and carotenoid (in high ratios of cocopeat) were sig-nificantly (at 5% level) higher in hydroponic treatment than in aquaponic treatment.

With the increase in the ratio of cocopeat to perlite in planting bed, the leaf fresh weight in-creased in hydroponic treatment, so that in this treatment the only cocopeat in planting bed pro-duced the highest leaf fresh weight whereas in aquaponic treatment, different planting beds had no significant effect on leaf fresh weight (Fig. 2). In hydroponic treatment, the highest root and crown fresh weight was observed in planting bed of 25% perlite + 75% cocopeat and crown growth was decreased as perlite rate increased. In aquaponic treatment, the plants grown on only cocopeat and only perlite planting beds produced the lowest crown and root fresh weights (Fig. 2). In hydroponic treatment, the highest and lowest runner lengths were observed in planting beds of 25% perlite + 75% cocopeat and only cocopeat, respectively. The lowest runner length was in the planting bed of only perlite and the highest one was in the planting beds of 25% perlite + 75% cocopeat and 75% perlite + 25% cocopeat (Fig. 3). The single leaf fresh weight was significantly greater in hydroponic treatment than in aquapon-ic treatment. It showed no significant difference between these two treatments (Fig. 4). Chloro-phyll a and b were significantly (at 5% level) higher in hydroponic treatment in planting beds of high cocopeat than in aquaponic treatment. In the latter treatment, the highest amounts of chlo-rophyll a and b were produced on planting bed of 75% perlite + 25% cocopeat. Also, total chloro-phyll was significantly higher in hydroponic treatment with higher rates of cocopeat than in aquaponic treatment. In hydroponic treatment, different planting beds did not affect total chloro-phyll, but in aquaponic treatment, the planting bed had significant effect and the highest one was observed in planting bed of 75% perlite + 25% cocopeat. Planting bed had no significant effect on carotenoid level, but the highest carotenoid level was observed in hydroponic planting sys-

64 S. Afsharipoor and H.R. Roosta / Plant Ecophysiology 2 (2010) 61-66

tem and on planting bed of only cocopeat (Fig. 5).

Discussion

Gul et al. (2005) reported that the concentra-tion of nutrition is higher in leaves of plants which receive inorganic nutrient solution than in that of plants which receive organic one, perhaps because of lower availability and release of nu-trients from organic sources. When nutrition level is under-optimal, leaf growth may be limited due to lower level photosynthesis and cell elongation (Heath-Buchholz, 1967). In aquaponic treatment in which the plants were fed by organic matter, the concentration of nutrients was probably lower and plant vegetative growth was lower than in

hydroponic treatment in which the plants were fed by inorganic solution.

In the current study, different ratios of per-lite:cocopeat in planting bed significantly af-fected most of the measured parameters. Coco-peat is an organic matter with a moderate ion absorption capacity and high water holding ca-pacity. Perlite has negligible cation exchange capacity and strong capillarity with enough air-storing apertures which can store water 3-4 times greater than its weight. The combination of these two factors affects nutrient holding capacity, bet-ter element exchange specially cations inside the bed and optimum distribution of moisture and air in root zone which consequently, affects the for-mation of rooting system, absorption of nutrients and plant growth (Wood et al., 1993). In a study on snake eggplant, Amiri et al. (2009) reported the highest root fresh and dry weight on planting beds of only rice hull and only perlite and the lowest ones on planting bed of 50% perlite +

Leaf

fres

h m

ass

(g p

lant

-1)

0

20

40

60

80

100

120

140

160AquaponicsHydroponics

Cro

wn

fresh

mas

s(g

pla

nt-1

)

0

10

20

30

Proportion of substra form

Roo

t fre

sh m

ass

(g p

lant

-1)

0

20

40

60

100 75 50 25 00 25 50 75 100

PerliteCocopeat

bc

aba a

a

dcd

dcd

d

cd cd

ba

bc

f

dede de

ef

cd

bc

aba

bc

f

de

ef

de

f

Fig. 2. Interaction of different planting beds and systems on strawberry leaf, crown and root fresh weight. Different letters show significant differences between treatments at 5% level.

Run

er le

ngth

(cm

)

0

10

20

30

40

50

60AquaponicsHydroponics

Proportion of substra form

100 75 50 25 00 25 50 75 100

PerliteCocopeat

ab

bcdabc

a

de

ef

ab

f

g

cde

Fig. 3. Interaction of different planting beds and systems on strawberry runner length. Different letters show significant differences between treatments at 5% level.

Sin

gle

leaf

fres

h m

ass

(g le

af-1

)

0

1

2

3

4AquaponicsHydroponics

Proportion of substra form

100 75 50 25 00 25 50 75 100

PerliteCocopeat

abcab

a a a

cdcd

d

cd cd

Fig. 4. Interaction of different planting beds and systems on strawberry leaf fresh weight only. Different letters show significant differences between treatments at 5% level.

S. Afsharipoor and H.R. Roosta / Plant Ecophysiology 2 (2010) 61-66 65

50% rice hull. In the current study, in hydroponic treatment, the lowest fresh weight was produced on only perlite planting bed and the highest one was produced on planting bed of 25% perlite + 75% cocopeat. In aquaponic treatment, the lowest fresh weight was produced on only perlite and only cocopeat planting bed and the highest one on planting beds of 25% perlite + 75% cocopeat and 75% perlite + 25% cocopeat (Fig. 2). The increase in the ration of perlite to cocopeat in planting bed increases the available oxygen in culture medium but the reverse decreases oxygen and increases water; on the other hand, low mois-ture holding capacity in perlite bed brings about moisture stress and decreases vegetative growth compared with the other beds. In the hydroponic treatment, fresh weight of leaf, crown and root increased as the ratio of perlite to cocopeat de-creased (Fig. 2). Also, runner length increased as the ratio of cocopeat increased in both treat-ments, but only cocopeat was found to be appro-priate (Fig. 3). The decrease in water and nutrient absorption is associated with the decrease in wa-ter holding capacity (Fotouhi Ghazvini et al., 2007). During water-deficiency periods, stomatal

conductance decreases which results in the de-cline of transpiration and since transpiration is a mechanism for absorbing elements and nutrients, the absorption of nutrients by roots and their transport from root to shoot decreases (Alam, 1999). In a study on the effect of perlite and zeo-lite planting beds on lettuce, Gul et al. (2005) reported that the lowest head was produced on only perlite bed and the growth of head aug-mented as the ratio of zeolite was increased in planting bed. The N and P absorption level was greater on zeolite and zeolite + perlite planting beds than on only perlite planting bed, but zinc absorption was not significant on different plant-ing beds. Woodward and Bennett (2005) reported that the concentrations of chlorophyll a and b decreased as the water level in cell decreased. In the hydroponic treatment, the concentrations of chlorophyll a and b were greater on planting beds with high ratio of cocopeat (Fig. 5). Conclusion

The results showed that most measured para-meters were better in hydroponic system and that

Chl

orop

hyll

a (m

g g-

1 FM

)

0.0

0.2

0.4

0.6

0.8

1.0AquaponicsHydroponics

Chl

orop

hyll

b (m

g g-

1 FM

)

0.00

0.02

0.04

0.06

0.08

0.10

Tota

l chl

orop

hyll

(mg

g-1 F

M)

0.0

0.1

0.2

Proportion of substra form

100 75 50 25 00 25 50 75 100

PerliteCocopeat

Proportion of substra form

100 75 50 25 00 25 50 75 100

PerliteCocopeat

Car

oten

oids

(mg

g-1 F

M)

0.00

0.02

0.04

0.06

0.08

0.10

cbc

a

de

ab

e

cd

a

c

c-fbcd

ab

ef

abc

f

def

a

bcdcde

ab aba

b

a

b ab

a

ab

a-dabc

ab

cd

ab

d

bcd

a

a-d

Fig. 5. Interaction of different planting beds and methods on pigments in strawberry leaves. Different letters show significant differences between treatments at 5% level.

66 S. Afsharipoor and H.R. Roosta / Plant Ecophysiology 2 (2010) 61-66 the planting beds of only perlite and only coco-peat were not suitable. Therefore, considering the cost of perlite and since cocopeat is imported, the mixture of perlite and cocopeat e.g. 50% perlite + 50% cocopeat and 25% perlite + 75% cocopeat is recommended for the cultivation of strawber-ries.

References

Alam, F.M. 1999. Nutrient uptake by plants under stress conditions, In: Pessarakli, M.(ed.), Handbook of plant and crop stress. Marcel dekker, New York. PP: 285-314.

Amiri, A.S., P. Aghdak and M. Mobali. 2009. Effect of different planting beds and hydrogel on vegetative and reproductive traits of eggplant. Proceedings for the First National Conference of Hydroponics and Greenhouse Productions. Oct. 22, Isfahan University of Technology, pp. 351-353.

Bruce, R.R., J.E. Plant, L.A. Harper and J.B. Jones. 1980. Water and nutrient element regulation prescription in non-soil media for greenhouse crop production. Commun. Soil Sci. Plant Anal. 11(7):677-698.

Fotouhi Ghazvini, R., G. Payvast, and H. Azarian. 2007. Effect of clinoptilolitic-zeolite and perlite mixtures on the yield and quality of strawberry in soil-less cul-ture. Hort. Sci.885-888

Gubbels, G.H. 1988. Effect of planting density on sun-flower hybrids. Plant Sci. 69: 1251-1254.

Gul, A., D. Erogul and A.R. Ongun. 2005. Comparison of the use of zeolite and perlite as substrate for crisp-head lettuce. Sci. Hort. 106, 464-471.

Heath-Buchholz, C. 1967. Uber die Dunkelfarbung des Blattgruns bei Phosphor mangel. Z. Pflanzenernaehr. Bodenkd. 118, 12-22.

Hochmuth, R. and M. Sweat. 1993. Hydroponic nutrient effluent is coverable energy resource. University of Florida. Report Suwannee Valley RREC. 91.

Inden, H. and A. Torres. 2004. Comparison of four Sub-strates on the growth and quality of tomatoes. Acta Hort. 644: 205-210.

Lee, B., J. Lee, S. Chung and B. Seo. 1999. Effect of container and substrate on growth and fruit quality of the hydroponically grown cucumber (Cucumis sati-vus L. cv. Chosaengnakhap) plants. Acta Hort. 483: 155-160.

Ronagi, A. and M. Maftoon. 2003. Hydroponics: a prac-tical guide for soil-less growers. Shiraz University Press, Iran.

Savido, N., A. Hutching, and E. Rakocy. 2007. Fish and plant production in a recirculating aquaponic system: a new approach to sustainable agriculture in Canada. Acta Hort. 742: 209-222.

Tuzel, I.H., Y. Tuzel, A. Gul, M.K. Merice, O. Yavuz and R.Z. Eltez. 2001. Comparison of open and closed systems on yield, water and nutrient consumption and their environmental impact. Acta Hort. 554: 221-228.

Valencia, E. and P. Flemming. 2000. Response of gui-neagrass to aquaculture irrigation during the dry sea-son. Caribean Food Crops Sosiety. 91-96.

Verdonk, O., D. De Vleeschauwer and M. De Boodt. 1982. The influence of the substrates on plant growth. Acta Hort. 126:251-258.

Wood, C.W., D.W. Reeves and D.G. Himelrick. 1993. Relationships between chlorophyll meter reading and leaf chlorophyll concentration, N status, and crop yield: A review. Proc Agron. Soc. N.Z., 23: 1-9.

Woodward, A.J. and I.J. Bennett, 2005. The effect of salt stress and abscisic acid on proline production, chlo-rophyll content and growth of in vitro propagated shoots of Eucalyptus camaldulensis. Plant Cell Tis-sue Organ Cult., 82: 189-200.