MARDI Res. J. I9(2) 1991:209-216

Intercropping okra with common leafy vegetables on Malaysian

peat and bris(Penanaman selingan bendi dengan sayuran daun di tanah gambut dan bris di

Malaysia)

A. C. Leong* and A. Zaharah**

Key words: okra, lciLfy vegcLables, intcrcropping, fertilizers, yield, net returns, peat, bris

Abstrak

Sistem penanaman selingan yang menggunirkan bendi dengan sayuran daun telah

dikaji selama dua pusingan tanaman cli tanah gambut dan bris dari tahun 1985

hingga 1987. Ka-lian di.lalankan dengan menggunakan reka benruk blok rawak

lengkap. Rawalan mengandungi kombinasi rawatan faktorial 4 x 2 berulang

dengan tanaman bcndi tunggal sebagai pctak kawalan. Penanaman selingan

bendi dcngan sayuran daun riciak mempengaruhi hasil bendi di kedua-dua jenis

unah. Pengesyoran baja scmasa bagi tanaman bendi (300:40:250 NPK kg/ha)

didapati mencukupi unluk tanaman bendi dan sayuran daun. Ini menunjukkan

peningkatan kecekapan penggunaan nutricn. Kepurusan daripada analisis daun

tidak menunjukkan pcrbczaan yang ketara dalam nutricn makro bagi pokok

daripada petak dengan alau ranpa lantunan selingan. Selain menambahkan

pendapatan, tanaman selingan ini .;uga dapat mengurargkan populasi rumput-

rumpai. sistem penanaman selingan ini mencatatkan hasil dan pulangan bcrsih

sehekrar yang lcbih tinggi berbanding dengan sistem pcnanaman tunggal'

Abstract

An intercropping system involvhg okra :[rd leafy vegetables was srudied ovel

two crop cycles on peat and bris from 1985 to 1987. A replicatcd 4 x 2 factorial

rial with an okra monocrop as the control was laid out in a RCB design'

lntercropping okra witr lcafy vcgcrables did not affcct the yield of okra on both

soil types. The currenr recommendcd fertilizer levcl (3fi):40:250 of NPK kg/ha)

for oh-a was sufficicnt ro support bot]r oka and thc intercrops, indicating an

improved efficiency of nurricnr urilization. Foliar analysis of okra showed no

significant {iffcrcncc in lcvels of major nulricnts in plants from plots with or

without an intercrop. Besides contr ibuting addit ional income, lhe intercrops could

also rcduce weed population. The intercropping systcm on Peat recorded high

yields and nct retums pcr hectare comparcd with the monocropplng systcm'

*Division of Honiculrure, MARDI Pear Soil Research Starion (Pontian), P.O. Box 506, 82000 Pontian, Johore,

Malaysia**Division of Lloniculrure, MARDi Tobacco Research Ccntre (Tclong), P. O. Box 186, 15720 Kota Bharu' Kelantan,

MalaysiaAuthors' full names: Leong Ah Chyc and Z-aharah Anffin

@ Malaysian Agr icul tural Research and Dcvclopment Inst i tute 1992

209

Intercropping okra with cmmon leafy vegetables

IntroductionIn Malaysia, the average farm size forvegetables is about I ha including non-planted area (Anon. 1981). With the limitedland area for vegetable cultivation, farmerscan increase land productivity by havingmore than a crop per year throughintercropping.

Intercropping a short-season cropbetween long-season annuals or perennialsis a common practice (Bees 1977). Thesystem increases productivity by getting ashort-season crop off during the earlygrowth stages of the long-season crop tratestablishes slowly. It has been reported thatintercropping often produced higher yieldsthan sole crops (Andrews 1972: Willey1979; Mead and Willey 1980; lpong 1990;l,eong and T,aharah l99l). The yieldadvantage in intercropping can becomemore substantial when component crops arecomplemenhry (Waghmare and Singh1984).

The initial establishment of okra isrelatively slow. This pcriod can be utilizcdfor intercropping short-term leafyvegetables. Intercroppin g leafy vegetablescan help to reduce weed infestation andincrease farm income. This study wasinitiated to determine the effects andcompatibility of several intercrops on theperformance of okra at two fertilizer levelson peat and bris.

Materials and methodsThe study was conducted on peat in Johoreand bris in Kelantan over two crop cycles.The first and second crop cycles werecarried out respectively in August 1985 andNovember 1986 on peat, and in April 1985and September 1986 on bris.

On peat, the main crop of okra wasplanted 3 weeks before the intercrops ofdifferent leafy vegetables. However on bris,okra was planted simultaneously in the firstcrop cycle and I week earlicr in the secondcycle. The common leafy vegetablcs,kangkong (lpomoea reptans Poir), lettuce(Lactuca sativa L.), white muslard (Brassica

210

chinensis L.), Chinese mustard (Brassicajuncea Coss), kailan (Brassica alboglabra)and bayam (Amaranthus viridis L.) wereevaluated as intercrops !o okra (Hibiscusesculentus L.)

Four types of leafy vegetables werestudied as potential intercrops with okra atfertilizer levels I and 2. The total fertilizersapplied for level 1, the cunentrccommended level for okra and level 2were 300:40:250 and 450:60:375 of N:P:Kkg/ha respectively. The extra fertilizer isequivalent to the amount required by theleafy vegetables. The fertilizers were appliedin e4ual iunounts at l, 3, 5, 6 and 7 weeksafter sowing of okra, except for P whichwas applied only as a basal dressing.

The four intercrops and the twofertilizer levels were arranged in a 4 x 2factorial in one block plus an okramonocrop as a control. A randomizcdcomplete block design, with three blocks,was used. The statistical analysis follows theanalysis of variance. The multiple range testin the form of LSD was carried out, oneamong the treatments summed over thefertilizer levels and the other LSD was tocatcr for uneven numbcr of replicatescomparing the control with the treatments.

Okra was planted at 80 cm x 80 cm.The planting distances for thc various leafyvegetables were 15 cm x 15 cm except forlettuce and kangkong which wcre spaced at25 cm x 15 cm and 15 cm x 0.5 cmrespectively. The spatial arrangement of tlemain crop and intcrcrop is shown inFigure l.

Liming witlr ground magnesiumlimestone (GNfl-) at 13 t/ha to raise the soilpH from 4.2 tD 5.0 in peat was carried outonly in the second crop cycle. On bris,liming with GML at 3 Vha was done in bothcrop cyclcs at I monft bcfore planting andin addiuon chicken dung at l0 t/ha wasapplied 3 days before planting. Traceelcments wcre applicd only to peat as abasal dressing, I day before planting. Yieldsof okra and the leafy vegctablcs wererccorded. The pcrcentages of N, P and K in

o o o o o o o

o o o o o o ox x

o o o o o o o

o o o o o o o

o o o o o o o

o o o o o o ox x

x = okra @ 80 crn x 80 crn

o = Chinese mustard, white mustard,kailan and bayam

@ 1 5 c m x 1 5 c m

o o o o o o

X X

o o o o o o

o o o o o o o

o o o o o o o

x = o k r a @ 8 0 c m x 8 0 c r no = lettuce @ 25 cm x 15 cm

A. C. I-eong and A. Zaharah

x = o k r a @ 8 0 c m x 8 0 c r n- = kangkong @ 15 crn x 0.5 cm

Figure I. Spatial arrangemenl of okra and leafy vegetable inlercrops

the leaf samples of oka on peat weredctermined for the second crop cycle only.Composite sampling was donc with one leaftaken randomly from the middle section ofeach okra plant, at the time of flowering.

MARDI's okra variety MKBe I andlocally available varicties of leafyvegetables were uscd.

Results and discussionOkra yieldIn the first crop cycle on peat, okra grown

together with Chinese mustard or kangkongrecordcd significantly highcr yields thanokra monocrop (Table /). No diffcrcnceswere detected among thc other treatmentsand fte okra monocrop. However, in thesecond crop cycle, no significant diflcrenceswere detected bctween the treatmcnts andthe monocrop, and among fte treatrnents.On bris, no significant differences betweenLhe treauncnts and monocrop, and amongLhe trcatrncnts were recordcd in both cycles(Table I ).

The low yield oi okra monocrop in thcfirst crop cyclc on peat was atfibutcd to alower plant population due to high mortalityof the okra secdlings. Generally, the results

indicatcd that intercropping okra with leafyvegetables did not affcct yield on peat andbris. In fact, complementary effect wasnoted in some treatments as indicated byhigher yield obtained compared with theyicld of okra monocrop.

No significant yield drfferences wererecordcd between the two lcvels of appliedfertilizers in both crop cycles and soil typcs(Table 2 ). Additional fertiliz.er applicationdid not increase the yield of okra. Thisshowed that the current recommendedfcrtilizcr level for okra was sufficient tosupport an addrtional intercrop of leafyvegenble. The present okra-leafy vegetablecropping system had improved theefficiency of nutrient utilization on pea.t andbris. No interaction effects were noted inboth cyclcs and soil types.

Leafy vegetable yieldsNo statrstical analysis on the yields wasdone because of the different speciesinvolved. Reasonably good yields wereobtained in both crop cycles on peat andbris (Table 3). The extremely high bayamyield obtained in tlre first crop cycle on bris

xx

xx

2tl

Intercropping okra with cornmon leafy vegetables

Table 1. l,east significant difference test on the yields of oka with leafy vegetable intercrops on pearand bris

Treatment Yield on peat (t^a) Yield on bris (t/ha)

lst CC 2nd CC lst CC 2nd CC

Okra + kangkongOkra + lettuceOkra + white mustardOkra + Chinese mustard 16.0Olcra + kailanOkra + bayamOkra (monocrop)S ELSD (57,)c.v. (E")"r-sD (5%)

2t.9 29.27.26 7 . 1 5

16.414.513.2

l 8.3r8.818.917.5

ri.sr .996.49

17.0

ri.s16.713 .617 .81.955.84

16.216.3

15 .0

r s.s15.80.571 .708.?2.07

ti.o0.902.69

15 .03.29

CC = crop cycle'LSD values for monocrop vs. treatment

Table 2. l,east significant difference test on the yields of oka and leafy vegetables at two fertilizerlevels

Fertilizer level Yield on peat (t/ha) Yield on bris (t/ha)

lst CC 2nd CC lst CC 2nd CC

Okral.evel 1l*vel 2SELSD (5%)c.v. (Eo)

leafy vegetableslrvel II*vel 2SE[sD (57o)c.Y. (qa)

14 .815.20.631.90

15.0

7.58.00.341.03

r5.0

r7 .0 16 .619.7 15.81 .41 1 .38459 4 . r4

2r.9 29.2

11.6 10 .39.3

16 .0t5.70.40r.208.7

4.34.49.9

0.50 0.62 0.221.53 1.87 0.66

16.2 21.8 t7.4CC = crop cycle

Table 3. Yields of leafy vegetable inr.ercrops on pear and bris

l,eafy vegetable Yield on peat (t/ha)intercrop

Yield on bris (t/ha)

lst CC 2nd CC lst CC 2nd CC

8.5 7.rWhite mustard 7 .5 I 1.4Green mustard 5.4

Kangkong[.ettuce

KailanBayam

9.6 14.5

9.9

6.6

i.t7.6

18 .3

6.45 . 2

-) .u

: -J . I

CC = crop cycle

2r2

A. C. l-eong and A. Tah.arah

Table 4. l,east significant difference test on the N, P and K contents in okra

leaves in the second crop cycle on peat

Treatment Content (%)

Cropping systemOkra + kangkongOkra + lettuceOkra + white mustardOkra + Chinese mustardOkra (monocrop)

SELSD (57o)c.v. g,)"LSD (5%)

Fertilizer levell.evel 1Level25r,LSD (5%)C.Y.(qa)

5.305.504.7 45 . 1 55.240.r90.589.20.71

5 . 1 1< a A

0 .140.419.2

0.680.660.620.610.u0.020.056.80.07

0.640.650.010.M6.8

3.283.223.353 . t 73.490.080.256.20.30

3 . r 8J . J J

0.060 . 1 86.2

.LSD values for monocrop vs. trcatment

was attdbuted to dclayed harvestingresuh.ing in over-mature plants.

No significant yield ditterences were

detected between the two fcrtilizer levcls in

both crop cycles on bris and the first cropcycle on paL (Table 2). Rcsult-s indicated

that the intcrcrops did not compcte fornutrients with the main crop. This wa^sprobably attributed to split-applications ofequal amounts of fertilizers, with theintercrops receiving two out of a mral offive applications.

The yields obtained from the leafyvegetables as intercrop can contributeadditional income and reducc the weedpopulation from the first 7 wrcks aftcrplanting of okra.

From the agronomic aspccts, the prcsent

intercropping systcm of okra, as he maincrop, is compatiblc witi lcafy vcgcLablcs asintercrop.

lrlPK nutrient content in okra leafOkra with white musLard as intercrop had

significantly lower N contcnt comparcd with

okra with lcttuce (Table 4). A significantlylower P contcnt was obuincd from okra

grown with Chinese mustard comparcd with

okra with kangkong. No signiticemtdifferenccs in N, P and K contcnts weredctcctcd between the ueatmcnts and thcmonocrop, and among the treatmcnts.

The differcnces in N and P contents tn

certain intercropping systems wcre,however, not rcflccted in the okra yicld

obtained, suggesting that intcrcropping hadnot affected the nutrient uptake of okra.

No differences were detccted in N, P

and K contcnts of okra bctween the twofertilizer levels (Table 4). This implied thatthc currcnt recommcnded ferrilizer levcl was

sufficicnt to support the intcrcropping of alcafy vegcrablc with okra.

Estimated total net returns per hectareThe production cost pcr hecnrc for thcdillcrent monocrops of okra (S5 967),lcttuce (S3 842), kangkong ($2 361) and thccrucifcrous vegetablcs like kailan, whitemus[ard and Chinese mustard (S4 915) were

obtained lrom Anon. (1988). The production

cost pcr hcctare for bayam was $3 007(Zaharah, A., MARDI, Telong, pcrs. comm.1991). Dctail costs of production pcr hccuuc

213

lntercropping okra with common leafy vegetables

for okra are shown in Appendix 1 (Anon.1988). No chicken dung but only l imc andtrace elemenls were applicd in peat, thercbyincurring an additronal cost of $137/ha forthe production of okra on pcat. Theadditional chicken dung applicd addcd anextra cost of $522lha on bris. Thcsc costfigures were used because of thc difficultyin collecting production costs bascd on smallexperimental plots. The averagc cx-larmprices for the duration of harvcst of thevarious vegctables involvcd arc listed inI'able 5. The estimatcd total nct rcturns forthe various cropping systems based on thcabove production cost and cx- farm priccsare shown in Table 6.

Only net rcturns from the variouscropping systems on pcat cxccedcd that of

the okra monocrop. No economic advantagewas notcd on bris exceDt in the okra andkailan intcrcropping system. This wasattributed mainly to diffcrcnces in the ex-farm priccs at tie two localities. Prices canbc two [o four timcs higher in Johorecompared witi tlrat in Kelantan for lhe samcvegetablc crop (Table 6). The pricediffcrences wcre probably due to a lowerdemand for vegeLablcs in Kelantan rclativeto Johore bccause of thc laLtcr's proximity tothe Singapore markct. This indicated thccconomic advant^agc of intcrcropping ovcrmonocropping in Lcrms of tonl ncl rcl.urns,providcd thc cx-farm prices wcre favourable.Whilc intercropping of lcerfy vegctables withokra is agronomically suitable, in Kelantanthe intcrcropping systcm may not bc

Table 5. Ex-farm priccs for oha and lcafy vcgetablcs on pear. and bris

Crop Ex-farm priccs on peat (S/kg) Ex-farm priccs on bris (S/kg)

1s t CC 2nd CC ls t CC 2nd CC

OkraKangkongL,ettuceWhite mustardChinese mustardKailanBayam

1 .240.121.000.980.82

2.061.041.001 . 0 1L00

0.800.30

0.801 .50*0.60

0.450.301.00*

0.80

0.5'7

Source Anon1 986

CC = crop cycle*Based on prices obtained in Johore Bharu as thcy werc not available from Kota Bharu

Table 6. Estimated total net rctums per hrctare for okra-lcafy vcgctables intcrcropprng ovcr lwo cropcycles and soil types

Cropping system Retums on pcat (S'000/ha) Retums on bris ($'000/ha)

1s t CC 2nd CC ls t CC 2nd CC

Anon.I 985a

Anon.1 987

Anon.1 985b

Okra + kangkongOkra + lcttuceOkra + white mustardOkra + Chincse mustardOkra + kailanOkra + bayamOkra (monocrop)

r 8 .816 .512.7L ) . L

u.8

44.335.939.434.9

i*

6.7

8.0I J . J

I z . )'1.7

0.40.2

-0.01

l\ .,

0.6

CC = crop cycle

a 1 AL t a

A. C. Irong and A. Zaharah

Plote I. Leafy vegetable iftercrops (lettuce and knngl<ong) about to be hanested, with olcra as tlw nnin

crop

practical for the above reasons. The bestcropping systems on peat with consistentlyhigh returns were okra with lettuce orkangkong (Plate I).

AcknowledgementsThe authors greatly appreciate Dr LeeChong Soon's critical comments on the draftand the statistical analysis. Thanks are alsodue to Mr Abu Zarim and Mr Mat TiOthman for technical assistance, Mr K. S.Chiew for the statistical analysis and MsSelamah Hj Ibrahim for typing themanuscript.

ReferencesAndrews, D. I. (1972). Intercropping with sorghum

in Nigeria: Eryl. Agric.8.' 139-50Anon. (1981). An agro-economic survey of

vegetable farming in Peninsular MalaysiaSerdang: MARDI

- (1985a). l-aporan harga barang-barangterpilih. FAMA, Johore Bharu (mimeo.)

- (1985b). l-aporan harga barang-barangte1pilih. FAMA, Kota Bharu (mimeo.)

- (1986). Laporan harga barang-barang terpilih.

FAMA, Kota Bharu (mimeo')

- (198?). Laporan harga barang-barang terpilih.

FAMA, Johore Bharu (mimeo.)

- (1988). Anggaran kos pengeluaran danpendapatan untuk tananan dan ternakanSerdang: MARDI

Beets, W. C. (1977). Multiple cropping. Worldcrops and livestock 29(1)z 25--7

Leong, A. C. (1990). The potential of long bean

and cucumber as intercrops with ginger on

Malaysian peat. MARDI Res. J. I8(1): 45-52

Leong, A. C. andZaharah, A. (1991). Effects of

different planting densities and schedules of

chilli on chilli- cabbage intercropPing' MARDI

Res. I . 19(1):9-16Mead, R. and Willey, R. W. (1980). The concept of

a land equivalent ratio and advantages in yield

from intercropping. Expl. Agri. 16:217-28

Waghmare, A. B. and Singh, S. P. (1984).

Sorghunr-legume intercropping and the effecs

of nitrogen fertilization. I. Yield and nitrogen

uptake by crops. E4pl. Agric.20:251-9Willey, R. W. (1979). Intercropping, is imporrance

and research needs I. Competition and yield

advantage. Field crop abstra.ts 32: l-20

215

lntercropping okra with cornmon leafy vegetables

Appendix l. Production cost per hectare for one season of okra

ltem Cost($)

Family labour

Man-day Cost'($)

Total($)

land preparation and making beds

Liming with GML 2.5 t@ $451t

Planting

Seeds6kg@$20lkg

Basal application (chicken dung)5 r @ $100^

Compound fertilizer (IIIPK blue)application (4x) 200 kC @ $825^

Spraying of insecticides/fungicides(6x)

Spraying of weedicide 9 L@ $2s.40tLPruning (2x)

Watcring

Harvestins

l l 3

r20500

2 150

263

5 l

40

10

l 5

5

l 0

l 5

1 8

) z

1 2

r20

400100

150

50

100

150

180

320120200

4002r3

150r20

550

2 250

413

23r

320r20

I 200Total cost of production 3 191 277 2 770 5 967

Source: Anon. (1988)'labour cost = $10/man-day

Acceptedfor publication on l0 JuLy l99l

2r6