Pertanika 12(3), 295-298 (1989)

Potential Productivity of HydroponicaUy-grown Tomatoes in theGenting Highlands, Malaysia

R. M. RAJA HARUNDepartment of Agronomy and Horticulture

Universiti Pertanian Malaysia43400 UPM Serdang, Selangor Darul Ehsan, Malaysia.

Key words: Potential productivity, hydroponically grown tomatoes.

ABSTRAKLima penanaman percubaan telah dijalankan untuk menguji potensi pengeluaran tomato di dalam sistemhidroponik kultur air dalam di Genting Highlands,. Malaysia (1,200 m atas paras laut). Tanaman tomatodibenarkan mempunyai hanya satu batang utama yang dilatih mengikut sistem berlapis atau sistem tegak.Varieti-verieti tak berterusan (determinate) dan berterusan (indeterminate) yang mengeluarkan buah-buahyang besar, sederhana dan kecil digunakan di dalam kajian int. Tanaman yang ditanam mengikut sistemberlapis tahan selama 9 bulan; tetapi jikalau ia hanya ditanam untuk selama 6 bulan, dua kali penanamandapat dilakukan setahun dengan memberi potensi hasil sebanyak 252-288 tan metrik/ha/tahun. Sistem tegakyang mengeluarkan ketiga-tiga saiz buah tomato mengeluarkan tiga penanaman setahun dengan anggaranhasil sebanyak 210-248 tan metrik/ha/tahun. Varieti-varieti tak berterusan mengeluarkan hasil-hasil yangberbeza; pengeluaran sebanyak tiga kali setahun akan memberi hasil sebanyak 131-216 tan metrik/ha/tahun.Hasil-hasil yang diperolehi dnripada sistem hidroponik ini adalah lima hingga 10 kali ganda lebih tinggidaripada hasil yang dapat diperolehi mengikut cam tanaman tradisional sama ada di tanah tinggi ataudi tanah rendah di Malaysia.

ABSTRACTFive trials were carried out to assess the potential productivity of tomatoes in a deep culture hydroponic systemin Genting Highlands (1,200 m a.s.L), Malaysia. The tomatoes were maintained as single-stemmed plantsusing the layering and vertical methods of plant training. Determinate and indeterminate varieties producinglarge, medium and small-sized fruits were investigated in these trials. Under the layering system, the indeter-minate plants could last for nine months but if crops were kept for only six months, two crops per year couldbe produced with a potential yield of 252-288 ton/ha/year. The vertical system could produce three crops peryear with a range of 210-248 tonnes/ha/year for the three sizes of fruits. The determinate varieties produceda wide range of yields and, with three crops per year, a yield range of 131-216 ton/ha/ could be expected.The yields obtained in the tested hydroponic system were at least five to ten times higher than those obtainedfrom traditional soil cultivation under highland and lowland conditions in Malaysia.

INTRODUCTIONTomatoes (Lycopersicon esculentum Mill), animportant vegetable crop in Malaysia, is tradi-tionally grown in soil, in the Cameron High-lands (1,000 to 1,500 meters above sea level).Tomato cultivation using hydroponics or soillessculture techniques, widely practised in Europe,have not gained acceptance by local commer-cial growers. One of the reasons for this is thehigh initial capital costs and the fear of not

achieving sufficient productivity to off-set thehigh initial capital outlay. There is thus theneed to assess the potential productivity oftomatoes under a hydroponic system and tomonitor potential problems that may affect theproductivity of the crop.

The following is a report on some trialscarried out to determine the potential produc-tivity of tomato, as a crop, in a hydroponicsystem (Kyowa Hyponica) using a number of

R.M. RAJA HARUN

commercially available tomato varieties. Deter-minate and indeterminate varieties were grown;the former being allowed to grow until theterminal inflorescence was produced while thelatter varieties were trained as single-stemmedplants using the vertical or layering techniques.

MATERIALS AND METHODS

LocationThe trials were carried out in a glasshouse usingthe hydroponic deep culture system at theHydroponic Unit, Universiti Pertanian Malaysia,Genting Highlands. This unit is situated at 1,200meters above sea level and has similar climaticconditions to the Cameron Highlands wheretomatoes are normally cultivated in Malaysia.The average day and night temperatures in theGenting Highlands are around 22°C and 17°C,respectively. Although temperatures vary verylittle throughout the year, days are more mistyand windy in December and January with windgusts of around 14-18 m/sec. In the glasshouses,however, air temperature can reach up to 35°Con bright sunny days although day tempera-tures of 25-30°C can be considered average.

The Hydroponic SystemThe Kyowa Hyponica deep culture hydroponicsystem (previously described by Lim andWan 1984; and Wan and Lim 1984) was thesystem used in the trials.This system consists oftroughs (1 m x 3 m x 10 cm) laid end to end,11 troughs per row with one meter spacing be-tween each row of troughs. Each glasshouse of1,000 m2 held 128 troughs each planted with 14plants. This gave a planting density of 4.7 plantsper m2 within each trough; but if paths betweenthe rows were included, the overall plantingdensity was 1.8 plants per m2.

Nutrient SupplyThe composition of the nutrient solution to theplants is as shown in Table 1. Nutrient solutionwas supplied to each trough from an under-ground tank by a submersible pump andcontinuously recirculated at the rate of 4 1/min per trough until the plants were two monthsold. Thereafter the rate of nutrient flow wasincreased to 6 1/min. These comparatively fastflow rates were considered necessary to main-

tain a high level of dissolved oxygen within the45 mm deep solution (for the first two months)and the 25 mm deep solution for the subse-quent months.

TABLE 1Composition of nutrient solution

(From Lim and Wan, 1984)

Major nutrients

NitrogenPhosphorousPotassiumCalciumMagnesiumIron

mg/1

20662

38613649

3.82

Minor nutrients

BoronZincManganeseCopperMolybdenum

mg/1

0.540.051.300.010.01

The electrical conductivity (E.C.) and pHof the nutrient solution were monitored dailyand maintained between 2.1 to 2.4 mS/sec and5.5 to 6.5, respectively. There was little fluctu-ation of E.C and pH of the nutrient solutionas the nutrient storage tank contained 15 m3

of solution in addition to 15 m3 in the troughsand pipes.

Cultural TechniquesThere is very little local experience in thehydroponic cultivation of tomatoes. In order toassess the overall potential production in ahydroponic system, as many available tomatovarieties as possible were used in order to givea better picture of the overall potential of thecrop within the system. The varieties grown weresupplied by various seed companies but it mustbe noted that the trials were not laid out tocompare performance of the varieties.

Seeds were sown directly in 2.5 cm gravelaggregates in perforated pots placed in thetroughs and supplied with continuously re-circulating nutrient solution for three weeks.Germination occurred within one week. Twoweeks after germination, selection was carriedout to retain only one normal seedling per potand these were then transferred to the maincultivation troughs with PVC mulching toprevent light from reaching the root regions.Each trough contained plants of the same varietyand the troughs were randomly allocated withineach row. A summary of the trials carried outis shown in Table 2.

294 PERTANIKA VOL. 12 NO. 3, 1989

POTENTIAL PRODUCTIVITY OF HYDROPONICALLY GROWN TOMATOES

TrialNo

12345

Date ofSowing

5/5/8616/2/8716/2/8716/2/8716/2/87

A

Durationof cropping

(days)

134 - 19550-5646-5646-5044-56

TABLE 2summary of the

Trainingsystem

LayeringVerticalVerticalVerticalVertical

(determinate)

trials

No. ofvarieties

45

1277

Plantsper

variety

7014141414

Size offruits*

MS

ML

L,M,S

* Size of fruit : L • Large, M = medium, S = small.

Three methods of plant training were tested.For the indeterminate varieties the plants weretrained vertically, into single stemmed plants,using rafia string. This was carried out by manualremoval of the side shoots. In Trial No. 1, theplants were maintained at a height of the 1.7m frame and lowered and layered twice weeklyto maintain this constant height (Walls 1977).Pruning of the lower leaves that did not sub-tend any fruit was regularly carried out whenharvesting commenced. This method of planttraining allowed the plants to be retained forup to nine months.

The second training technique practisedin Trials No. 2, 3 and 4 used the vertical systemwhereby the indeterminate varieties, also trainedas single-stemmed plants, had their growingpoints removed upon reaching the top of theframe at 1.7 m with around 6 or 7 trusses. Underthis system, the plants were removed once allthe trusses had been harvested.

In the third system, Trial No. 5, the plantswere also trained as single stemmed plants andsupported with rafia string until a final deter-minate inflorescence terminated further growth.

To assist in fruit-set, opened flowers weresprayed with a 0.5 percent solution of sodium-4-chloro-hydroxy phenoxy acetate ("Tomat-lane") on alternate days.

RESULTS

Trial No. 1: Production under theLayering SystemUnder this system, the crop remained in pro-duction for seven months for varieties"Firedance" and "Precodor" and around nine

months for varieties "Gross Lisse" and "PinkFR26'\ For the former two varieties, the residualeffects of the fruit inducing hormone used couldbe discovered; the young leaves produced inthe later stages were deformed, elongated andleathery with overall reduction in leaf area. Asa consequence of this reduced leaf area, thefruits formed in the later trussess were unfilled,possibly indicating an insufficient supply ofassimilates.

Management of the crop under this layer-ing system was laborious as the plants had to belowered twice weekly to maintain a constantheight. The lower leaves which no longersubtended the fruit had to be regularly removed.When pruning was delayed, air circulationwithin the canopy was reduced resulting inincreased infestation of powdery mildew(Erysiphe sp.). This infestation could, however,be easily controlled by the use of Triforine("Saprol") at the rate of 0.19 ml a.i./litre ofwater.

With regard to insect pests, only theoccasional caterpillar was observed and wasremoved by hand. Thus, no insecticide applica-tion was necessary for the crop.

The mean yield for the varieties underthis system of training (Table 3) was 15.16 kg/plant (S.E. = 0.375) for the longer durationcrop (194 days) and 9.51 kg/plant (S.E. = 0.057)for the shorter duration crop (135 days).Average fruit production per day of croppingwas between 70-80 g/plant. If the crop hadbeen retained for only six months to overcomesome of the management problems i.e. 100 daysof cropping after commencing harvest at around

PERTANIKA VOL. 12 NO. 3, 1989 295

RM RAJA HARUN

traditional method of cultivation in the soil.Tomato yields in the Cameron Highlands areonly around 20-35 tonnes/ha/season (Nordinet aL 1986) whereas those from the lowlandsare around 28.5 tonnes/ha (Haron 1987) to30.8 tonnes/ha (Vimala 1985). These crops,unlike those under the present hydroponic sys-tem, are grown without protection and areexposed to the vagaries of weather. They arenot sprayed with hormone to assist fruit set anddevelopment and are normally affected byfungal pests such Phytophthora infestans (Nordinet aL 1986).

Under the present investigation a maxi-mum yield of around 280 tonnes/ha could beexpected. This is still lower than that typicallyobtained in the South coast of the UnitedKingdom which is around 328 tonnes/ha orhigher in some cases (van de Vooren etaL 1986). With further selection of varietiesmore suited to the tropics and experience withthe crop and nutrient manipulations, highertomato yields can be anticipated. This mayeventually convince the local growers to choosehydroponics as a commercial method for thecultivation of tomatoes.

ACKNOWLEDGEMENTSThe author wishes to thank En. Hanib Ali fortechnical assistance in data collection andmanagement of the trials. The supply of seedsamples by the various seed companies is alsogratefully appreciated.

REFERENCESHARON, A, 1987. Potensi Tomato jenis "MT 11"

dan Jenis "Local White" di Tanah Gambut. TeknoLSayur-sayuran 3: 35-38.

LIM, E.S. and C.K. WAN. 1984. Vegetable Grow-ing in the Tropics Using a Two-phase SubstrateSystem of Soilless Culture. Proc Sixth Int. Congr. onSoilless Culture, Wageningen. PP 317-328

NORDIN, M. S,, S. A. RAHMAN, and A. ABDULLAH.

1986. Research on Chemical Control againstTomato Late Blight in Cameron Highlands. 2ndhit. Conf. Plant Protec. in the Tropics. GentingHighlands 17-20 Mar. 1988. Extended AbstractsNo. P-17.

van de VOOREN, J., G. W. H. WELLES and G.

HAYMAN. 1986. Glasshouse Crop Production.In, The Tomato Crop, ed. J.G. Atherton, and J.Rudich. London: Chapman and Hall. pp. 581-623

VIMALA, P. 1985. Effects of Varying Rates ofNitrogen, Phosphorous and Potassium on the Per-formance of Tomato on Peat. TeknoL Sayur-sayuran1: 49-53.

WALLS, I. G. 1977. Tomato Growing Today. 2ndEd. Publ. Newton Abbot: David and Charles.235 pp.

WAN, C. K. and E.S. LIM. 1984. Growing Crops inPots Containing Gravel Chips by the RecirculatingFlow Technique under Tropical Conditions. Proc,Sixth InL Congr. on Soilless Culture. Wageningen.pp 751-762.

(Received 2 November, 1987)

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