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EFFECTS OF INTERCROPPING PATTERN ON SOYABEAN AND MAIZE YIELD IN

CENTRAL RIFT VALLEY OF KENYA

Kipkemoi, P.L1, Wasike, V.W.

2., Ooro, P.A.

1, Riungu, T.C

3, Bor, P.K

1. and Rogocho, L.M

1.

1 KARI-Njoro

P.O Njoro, Kenya

E-mail: Karinjoro@karinjoro.org

2 KARI Headquarters

P.O Box 58711

NIAROBI

3 KARI-Muguga

ABSTRACT

Intercropping is being adopted as a method of crop production in Kenya. Farmers often intercrop legumes with

non-legumes. A study to assess the productivity of maize (Zea mays L) and soybean (Glycine mux (L.) Merr.)

in sole cropping and intercropping systems was done at National Plant Breeding Research Centre – Njoro in

1997 and 2001 seasons. Soybean was seeded in one, two or three rows between two maize rows and on the

same row with maize. The maize population densities of about 44,000 and 36,000 plants per hectare were used

in 1997 and a uniform plant population of about 44,000 plants per hectare was planted in 2001. The control

treatments were sole cropping maize and sole cropping soybean at about 55,000 and 222,000 plants per hectare

respectively. The trial layout was completely randomized block design with four replicates in both years.

Intercropping significantly (p=0.05) reduced soybean number of pods per plant and 100 seed weight in 1997 but

not in 2001. Grain yield of soybean in the soybean- maize intercrop was reduced by 59% to 75% in 1997 and

21% to 68% in 2001 compared to sole cropped soybean. Land equivalent ratio on both years was greater than

one, indicating that this cropping system is profitable in terms of land utilization. It was concluded that maize is

a dominant component crop in maize and soybean intercropping system and that it is advantageous to intercrop.

Key words: Intercropping, sole cropping, intercrop, Land equivalent ratio (LER), maize. Soybean

INTRODUCTION

Intercropping is the growing of two or more crop species simultaneously on the same field. This is a common

practice in most countries in the tropics. Maize, potatoes, oilseed crops and pulses are commonly used as

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component of intercrops combination crops in Kenya. There are several possible benefits of intercropping

legumes with non-legumes. In terms of land use efficiency intercropping is regarded as more productive than

sole cropping. (Andrew and Kassam, 1976). Higher nutrient uptake and better water use efficiency have also

been suggested. (Dallal, 1974, Baker and Norman, 1975). Various reasons have been given for the adoption of

the system in Kenya (Mwania, et al. 1990). These include risk of crop loss due to adverse environmental

conditions, need for balanced diet, and the desire to optimize the use of labour and to optimize the use of land.

The advantage is often expressed as a land equivalent ratio (LER). LER greater than one indicates that more sole

cropped land than intercropped is required to produce a given amount of product. The LER of maize-soybean

intercrops ranged from 0.98 to 1.55 in Zambia (Mwipaya, 1990), and 1.2 to 1.8 in Ethiopia (Kidane. et al. 1990).

Nitrogen fixing legumes generally do not need Nitrogen fertilizer, whereas, the non-legumes requires additional

mineral nitrogen for optimum growth. Besides its own nitrogen requirement, legumes may contribute additional

nitrogen to the soil, which can be used by the component crop in the intercrop or the succeeding crops. Soybean

production in the farming system of central Rift Valley is gaining increased awareness as a good source of

human protein food. The objective of the study was to evaluate the productivity of intercropping soybean with

maize.

MATERIALS AND METHODS

The study was carried out at Njoro (0o 20'

S and 35

o56'E) in Nakuru District, Kenya, which lies at an altitude of

2160m above sea level, in the agro-ecological zone LH3 . The soils are vintric mollic andosols that are well

drained, deep to dark reddish brown friable and silt clay soils with humic top soil. The rainfall is bimodal and

well distributed (886 mm/yr) with an average maximum and minimum temperatures of 24 o C and 8

o C,

respectively (Jaetzold and Schmidt, 1983)

The field was under commercial wheat crop the previous year in both years. The experimental design was a

completely randomized block design replicated four times. The soybean cultivar planted was Hill and its

component crop was maize hybrid H614D in 1997. The treatments included sole soybean, one row of soybean

between two rows of maize, and two rows of soybean between two rows of maize, soybean planted in the same

row with maize and sole maize crop. Maize was spaced at 75cm by 30cm and 90cm by 30cm with population

of about 44,000 and 37,000 plants per hectare respectively. The gross plot dimensions were 6m by 3m. The

plot received 100 kg/ha of Diammonium phosphate at planting. In both years the test crops were hand planted.

The plots were maintained clean by weeding three times and insect pests of soybean were controlled by

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application of insecticides. Five plants from each plot were sampled randomly for the determination of height

and yield components. The whole plot was harvested for soybean seed yield. A similar trial was planted in the

long rains of 2001. The differences to treatments of 1997 is the inclusion of three rows of soybean between two

rows of maize and the fact that a uniform population of44, 000 plants/ha of maize was used. The soybean

cultivar planted was EAI 3600 instead of cv Hill. Maize variety used was same as in 1997. The data collected

was subjected to an analysis of variance using computer SAS programme. Intercropping was assessed, relative

to that of sole crops, by use of Land Equivalent Ratios (LERs), which is defined as the proportion of land area

that is required for sole cropping to produce the same yields as intercropping (Mead and Willey, 1980). The

LERs were calculated using the formula:

LER = Ym/Sm + Ys/Ss

Where Ym and Ys are the respective yields of maize and soybean in intercropping and Sm and Ss are the

respective yields of maize and soybean in sole cropping.

RESULTS AND DISCUSSION

In 1997, the soybean plant heights and the number of pods per plant were affected by intercropping with maize.

When intercropped the pods were significantly (P=0.05) reduced as compared with sole soybean treatment. The

seed weight was also significantly (p=0.05) reduced by intercropping (Table 1). Different pattern of

intercropping soybean in maize did not significantly affect any of the yield components.

Table 1: Soybean yield components as affected by intercropping with maize at Njoro in

1997

Treatment Height (cm) Pods/plant Seeds/pod 100 seed weight (gm)

Sole soybean 47.8 40.3a 2.00 10.8a

One row1

48.9 17.5b 1.95 10.2ab

Two rows1

50.4 20.0b 1.70 9.6b

One row2

50.0 21.8b 1.85 10.1ab

Two rows2 49.0 17.0b 2.10 10.0ab

Same row2

45.0 21.5b 2.00 9.7b

C.V% 9.1 25.9 16.1 5.9

Means followed by the same letter are not significantly different at the 5% level

Maize spacing: 90cm by 30cm

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Maize spacing: 75cm by 30cm

In 2001 soybean plant heights at maturity, pods per plant and seeds per pod were not affected by intercropping

with maize.

Soybean grain yield was reduced by 59% to 75% when intercropped with maize (Table 2) but the yield of maize

was not significantly (p=0.05) affected. In 2001 Soybean yields were reduced by 21 to 68% as compared to the

sole cropped soybean (Table 3). In both years maize was the dominant component ot the intercrop in terms of

partial LERs.

Table 2: Seed yield and land equivalent ratios of maize and soybeans in sole crop and

intercrop systems planted in 1997 at Njoro

Treatment Yields (kg/ha) Partial LERs Totals LERs

Maize Soybean Maize Soybean

Sole maize1

1982 - 1.0 - 1.0

Sole soybean1 -

1115a - 1.0 1.0

One row1

2554 280b 0.98 0.32 1.54

Two rows 1 2247 390b 1.11 0.60 1.48

One row2 2048 310b 0.85 0.79 1.31

Two rows 2 2066 440b 1.04 0.22 1.26

Same row 1

2976 455b 1.50 0.41 1.91

C.V. % 29.6 22.6

Means followed by the same letter are not significantly different at the 5% level.

1Maize spacing: 90cm by 30 cm

2Maize spacing: 75cm by 30cm.

Table 3: Seed yield and land equivalent ratios of maize and soybeans in sole crops and

intercrop systems planted in 2001 at Njoro

Treatment Yields (kg/ha) Partial LERs Totals LERs

Maize Soybean Maize Soybean

Sole maize1

3585 - 1.0 - 1.0

Sole soybea1 776a - 1.0 1.0

One row1

3500 252b 0.98 0.32 1.30

Two rows 1

3996 462ab 1.11 0.60 1.78

Three rows1 3062 613ab 0.85 0.79 1.64

Same row 1

3430 392b 0.96 0.51 1.47

C.V. % 38.9 45.5

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Means followed by the same letter are not significantly different at the 5% level.

1 Maize spacing: 75cm by 30cm.

The yields obtained from two and three rows of soybean between maize rows spaced at 75cm by 30cm were

statistically similar and higher than other intercrop treatments. Ezumah et al (1987) and Wahua et al (1981)

reported 55% to 61% and 40% to 55% reduction of cowpea yield when cowpea was intercropped with maize.

Intercropping of maize planted at a population of 53330 plant/ha with soybean at 266660 plant/ha reduced the

number of soybean pods per plant by 46% and the seed yield per hectare by 42% and 46% in the early (may)

and late (July) seasons respectively (Muoneke et al (2007). Maize is taller than soybean in stature. The higher

yield reduction of soybean when intercropped with maize could be due to interspecific competition and

depressive effect of maize crop. Van der Meer (1989) noted that both competition and facilitation take place in

many intercropping systems, and that it is possible to obtain the net result of land equivalent ratio (LER where

the complementary facilitation is contributing more to the interaction than the competitive interference. Thus, an

LER>1 could result from low interspecific competition or strong facilitation.

Yield advantages were determined using Land Equivalent Ratio (LER). The total LER in both years for all

intercropping treatments were greater than one indicating that all the treatments had an advantage in land use

(Table 2 and 3). In 1997, the intercropping of soybean and maize seeded in the same row resulted in superior

LER than the other treatments (Table 2). These results are similar to those reported by Mutungarimi et al

(2001) who observed that the intercropping of maize and beans in the same row resulted in highest LER value to

other intercrops. In 2001, two rows of soybean planted between two rows of maize resulted in superior LER

(Table 3). This is in agreement with the results reported by Finlay (1975) who observed that in maize/soybean

and sorghum intercrops on alternate row arrangement was superior to planting on the same row or the same

hole. In this study, the observed differences in LERs in the two years could be attributed to the different

cultivars of soybean used as intercrops with maize.

Although two different soybean cultivars were used in the two years of this study to intercrop with maize, it was

apparent that maize was the dominant component in the intercrop. There seemed, though, that soybean cultivar

differences exist in their competitive abilities. Intercropping involves competition, and as such can be viewed as

a kind of stress. Cultivar selection should, therefore, be directed at minimizing intercrop competition and

maximizing complementary effects. It is, however, advantageous to intercrop maize with soybeans since yield

of maize is not significantly affected and at least some yield of soybean is realized from the same piece of land.

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CONCLUSION

The results of this study showed that soybean and maize could be intercropped. Intercropping is much more

efficient in utilizing the available resources than sole cropping as indicated by the high LER values

ACKNOWLEDGEMENT

The authors wish to thank GTZ soybean project for providing funds for the study in 1997 and the Centre

Director, National Plant Breeding Research Centre for encouragement and facilitation of the study.

RERERENCES

Andrews, D.J. and Kassam, A.H. (1976). In multiple cropping edited by Paperdick, R.I. Sanchez, P.A. and

Triplett, G.B. pg. 1-10. Special publication No. 27. America society of Agronomy. Madison, Wisconsin.

Baker, E.F.I. and Norman, D.W. (1975). Cropping systems in Northern Nigeria. Proc. Cropping system

workshop. IRRI. Los Banos, Phillipines. Pg. 334-336.

Dallal, R.C. (1974). Effect of intercropping maize with pigeon peas on grain yield and nutrient uptake.

Experimental. Agriculture. 10:219-224.

Ezumah, H.C., Nguyen Ky Nam and Walker, P. (1987). Maize-cowpea intercropping as affected by nitrogen

fertilization, Agromomy Journal, 79: 275-280.

Finlay, R.C. (1975). Intercropping soybean in cereals. In proceedings of Regional soybean conference, Addis

Ababa, 14-17 October, 1974.

Jaetzold, R. and Schmidt, A. (1983) Natural conditions and farm management handbook of aKenya Vol. 2B.

Central Kenya (Rift Valley and Central province). Ministry of Agriculture, Republic of Kenya 121-

154:379.404

Kidane G. Amare A., Adhonon N., Legesse D. and Woldeyeuss.(1990). Cereal/Legume intercropping research

in Ethiopia. In Waddington, R.S., A.F.E. Palmer, and O.T. Edje eds: Research methods for cereal/legume

intercropping: Proceedings of a workshop on research methods for cereal/legume intercropping in Eastern and

Southern Africa. Mexico, D.F: CIMMYT.

Mead, R. and Willey, R.W. 1980. The concept of a ‘Land Equivalent ratio’ and advantages in yields from

intercropping. Experimental Agriculture. 16: 217-218.

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Muoneke C.O., Ogwuche M.A.O. and Kalu B.A. 2007. Effect of maize planting density on the performance of

maize/soybean intercropping system I a gunea savannah agroecosystem. African journal of Agricultural

research. PP 667-677

Mutungarimi A., Mariga I., and Chivinge O. 2001. Effects of maize density, bean cultivar and bean spatial

arrangement on intercrop performance. African Crop Science Journal.9 (3) 487-497.

Mwania, N.W., Omunyin, M.E., Chumo, J.J. Muriithi, C.N. and Milikau, R.L. 1990. Cereal.Legume

intercropping research in Kenya. In Waddington, R.S., A.F.E. palmer, and O.T. Edje eds: Research methods

for cereal/legume intercropping. Proceedings of a workshop on research methods for cereal/legumes

intercropping in Eastern and Southern Africa, Mexico, D.F.: CIMMYT. Pp 165-175

Mwaipaya, A.M. 1990. Intercropping research experience in Zambia. . In Waddington, R.S., A.F.E. Palmer,

and O.T. Edje eds: Research methods for cereal/legume intercropping: Proceedings of a workshop on research

methods for cereal/legume intercropping in Eastern and Southern Africa. Mexico, D.F: CIMMYT. Pp184-189

Wahua, T.A.T., Babalota, O. and Akenya, M.E. 1981. Intercropping morphologically different types of maize

with cowpeas: LER and growth attributes of associated cowpeas. Experimental Agriculture. 17: 407-413.

Ugen M.A.and H.C. Wien (1996). The effect of mixture proportions and fertilizer nitrogen on morphology,

insect pest damage, competition and yield advantages in a maize/bean intercrop. African Crop Science

Journal,Vol. 4. No.l, pp. 41-49

Van der Meer J (1989). The Ecology of Intercropping. Cambridge University Press, New York.