J. Agronomy & Crop Science 171, 351—357 (1993)© 1993 Paul Parey Scientific Publishers, Berlin and HamburgISSN 0931-2250

Department of Crop Science, University of Maiduguri

Growth and Yields of Intercropped Sorghumand Sunflower {Hdianthus annuus L.) in Semi-arid Nigeria

I. A. ADETUNJI'-'

Author's address: Dr. I. A. ADETUNJI, Department of Crop Science, University of Maiduguri, Nigeria.^Author's present address: Department of Agronomy, Ladoke Akintola University of Technology, Ogbo-moso, Nigeria.

With 6 tables

Received November 16, 1992; accepted January 14, 1993

Abstract

Effect of five planting patterns on the growth, yield and yield components of intercropped sunflower andsorghum was studied during 1989—90 planting seasons at University of Maiduguri, Nigeria. Generally,intercropping depressed the performance of sorghum more than sunflower. Sorghum plants grown inalternate hills with sunflower had the shortest stems, the least dry matter and total seed yields per hectare,while the highest dry matter and seed yields were obtained from sorghum planted in five alternating rows withsunflower. Similarly, in sunflower, plants grown in five alternating rows with sorghum had the highest yieldscompared with other planting patterns, but there were no significant differences in the dry matter and totalseed yields of sorghum and sunflower intercropped in three and five alternating rows. Light transmission, leafarea index and yields of both crops followed similar trends under the various planting patterns. Interplantingin five alternating rows that allowed the highest leaf area also allowed the lowest light transmission andproduced the highest yields. Land use efficiency was highly improved under three and five rows mterplantingby 52 and 74 % respectively.

Key words: Sorghum, sunflower, intercrop, growth, yield.

Introduction

Intercropping is a common feature of foodcrop production in the semi-arid region ofnorth eastern Nigeria. The cropping systemusually involves a staple food crop like sor-ghum or millet intercropped with groundnut.However, on account of several productionproblems such as 'Rossette Malady' of1975—77, groundnut production had nevermatched the demand in Nigeria. Thus sun-flower was introduced into Nigeria agricultureto supplement groundnut, as a source of cook-ing oil (ADO and TANIMU 1988). Despite sun-flower's increasing importance, it has only re-cently been the subject of meaningful ag-ronomic studies with major research pro-

grammes at the Institute for Agricultural Re-search, Ahmadu Bello University, Zaria whereseveral accessions are maintained.

Sunflower has not been used as a componentof crop mixture in Nigeria, while substantialprogress have been made in intercroppinggroundnut with other cereal crops such assorghum and millet (BAKER 1980). Althoughsunflower is rarely used in intercropping, it hascharacteristics desirable for intercropping. Theerect growth, production under wide rowspacing, large and easily harvested head, andits potential use as a staple food suggest that itwould be an ideal intercrop for subsistenceagriculture in Nigeria. There are conflictingreports about the suitability of sunflower as an

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352 ADETUNJI

intercrop. While RICE (1974) and ROBINSON

(1984) reported strong allelopathic effects ofsunflower on other crop species in USA.MBIZA (1988) successfully intercropped sun-flower with maize, sorghum and millet in thedrier regions of Tanzania. Similar informationon sunflower under intercropping conditionsis required in Nigeria.

The work reported here was therefore con-ducted to investigate the effect of intercrop-ping sunflower with sorghum in different spa-tial arrangements on the growth and yields ofthe two crops.

Materials and Methods

Two field trials were conducted during the plantingseasons (June—September) of 1989 and 1990 at theTeaching and Research Farm, University of Maidu-guri. Maiduguri lies on latitude l l l°04'N and lon-gitude 13°05'E. The total rainfall during the experi-mental period was 533.8 mm in 1989 and 407.1 mmin 1990. The 0—15 cm soil layer is 91.16 % sand,1.5 % clay and 7.88 % silt, with a pH of 6.42,0.473% organic C, 0.077% total N, 0.151 ppmavailable P and 0.009, 0.064 and 0.015 meq/100 g ofK, Ca and Mg respectively. The soil is classified astypic ustipsamment (USDA 1975).

The sunflower cultivar used in this study wasIsaanka (an open pollinated cultivar of mediumheight which matures between 90—100 days afterplanting), obtained from institute of AgriculturalResearch (IAR), Samaru, Zaria. A 110-day sorghumcultivar recommended for this area, BES, was usedin all trials.

Following ploughing and harrowing, fertiUzer(NPK 1 5 : 1 5 : 15) was applied a the rate of 120 kg/ha. Thereafter, four seeds of sorghum and sunflowerwere planted per stand, on the flat during the secondweek of June in both planting seasons. The spacingused for both crop species was 30 X 90 cm as amonocrop and in mixed cropping. The followingplanting patterns were used: (i) Sole crop of sor-ghum, (ii) Sole crop of sunflower, (iii) Sunflower andsorghum in alternate hills in the same row, (iv)Sunflower and sorghum in alternate row, (v) threerows of sunflower alternating with three rows ofsorghum and (vi) five rows of sunflower alternatingwith five rows of sorghum. These treatments werelaid out in a randomized complete block experimen-tal design, with four replications. There were 30rows per plot and 16 plants per row. There were 24plots, each measuring 26.1 x 4.5 m. The total ex-perimental area was 21 X 161.6 m. Both sunflowerand sorghum were thinned to one plant per hill twoweeks after emergence.

For both crops, growth parameters were measuredat complete anthesis. For sunflower, the followinggrowth parameters were measured from 20 random-ly selected plants: Plant height, stem diameter, leavesper plant, leaf area and leaf area index and lighttransmission at 65 days after planting (DAP). Theyield and yield components measured include, seedsper head, head diameter, 1000-seed weight, yield perplant and yield per hectare. In sorghum, plantheight, culm diameter, leaves per plant, leaf area andleaf area index and percent hght transmission at 65DAP were also measured. The yield and yield com-ponents measured include seeds per head, paniclelength, panicle diameter, yield per plant and yieldper hectare. Days to 50 % anthesis were noted forboth crops. Leaf area per plant was determined on anautomatic leaf area meter, model LI3000. This waslater converted to leaf area index (LAI). Light trans-mission was measured with a Lambda portable lightmeter LI-COR model 185.

Seed yield on a 13 % moisture basis was deter-mined each year from ten 2 m rows and used tocompute the land equivalent ratio using the formulabelow:

Xa Xb

MA MBWhere Xa and Xb are the component yields of cropsA (sunflower) and B (sorghum) grown within amixture, and MA and MB are the yields of monocul-tures of A and B on a similar units area. Treatmentdifferences were tested by two-way analysis of var-iance (LITTLE and HILLS 1975) from which the leastsignificant differences (at P 0.05) were calculated.

Results

The 1989 season plants were bigger and morevigorous than the 1990 season plants due toreduced rainfall during the growth of the lat-ter. Consequently, the growth, yields andyield components of 1989 season plants weregenerally higher than that of 1990 seasonplants. Nevertheless, the effects of the treat-ments on the growth and yields of the plantswere similar for both seasons, so that the meanof the two years data are described below.

Effect on Growth of Sunflower and Sorghum

The growth of both sunflower and sorghumwhen grown as sole crops were superior to allother planting methods (Tables 1 and 2).

In sunflower, neither the number of the daysto 50 % flowering nor leaf number per plantwas significantly affected by any of the plant-

Intercropping^ Sunflower with Sorgl 353

Table 1. Effect of planting patterns on the growth of sunflower planted either as sole crop or in mixtures withsorghum

Planting patternsof sunflower

No. of daysto 50 %anthesis

No. ofleavesplant

Plantheight(cm)

Stemdiameter

(cm)

Totaldry matteryield (t/ha)

Sole cropAlternate hill with sorghumBetween row of sorghumThree rows of sunfloweralternating with 3 row of sorghumFive rows of sunfloweralternating with five rowsof sorghumLSD (P 0.05)

575858

56

57NS

20.218.419.1

20.0

20.4NS

126.8121.1122.6

123.5

124.33.11

1.91.11.3

1.6

1.80.41

5.23.13.6

4.8

5.01.6

NS = Not Significant.

ing methods (Table 1). Sunflower started flow-ering within the first five weeks of growth andattained 50 % flowering between 7—8 weeksafter planting in all the planting patterns. Thesole crop of sunflower was significantly tallerthan those planted in alternate hills and insingle alternating rows with sorghum but notsignificantly taller than those planted in threeand five alternating rows with sorghum. Sun-flower plants in alternate hills with sorghumhad the shortest height. Compared with solecrop, intercropping also had significant effecton stem diameter and total dry matter yield ofsunflower except when intercropped at three

and five alternating rows with sorghum(Table 1).

Intercropping, irrespective of the pattern didnot affect number of days to 50 % heading insorghum, while plant height, culm diameter,leaf number and total dry matter yield weresignificantly affected by planting patterns(Table 2). The sole-crop sorghum were signifi-cantly taller than those planted between rowsof sunflower but only slightly taller than thoseplanted in three and five alternating rows withsunflower. When compared with sole crop,intercropping significantly reduced culmdiameter, leaves per plant and total dry matter

Table 2. Effect of planting patterns on growth of sorghum planted either as sole or in mixtures with sunflower

Planting patternsof sorghum

Sole cropAlternate hill with sunflowerBetween rows of sunflowerThree rows of sorghumalternatine with 3 rowof sunflowerFive rows of sorghumalternating with five rowsof sunflowerLSD (P 0.05)

No. of daysto 50 %heading

828381

80

79

NS

Plantheight(cm)

108.891.6

105.7

103.5

104.86.10

Culm diameterper plant

(cm)

7J

5.25.8

7.3

7.61.02

Leavesper

plant

11.1

9.210.1

10.5

10.70.71

Total drymatter yield

(t/ha)

6.7

3.84.6

5.7

5.8

2.02

NS = Not Significant.

J. Agronomy & Crop Science, Vol. 171 (5) 25

354 ADETUNJI

Table 3. Effect of planting patterns on the yield and yield components of sunflower planted either as sole cropor in mixture with sorghum

Planting patternsof sunflower

Headdiameter

(cm)

Seedsper land

1000-seedweight

(g)

Seed yieldper plant

(g)

Seed yieldper ha(t/ha)

Sole cropAlternate hill with sorghumBetween row of sorghumThree rows of sunfloweralternating with 3 rowsof sorghumFive rows of sunfloweralternating with five rowsof sorghumLSD (P 0.05)

15.512.113.3

14.8

15.31.41

760.2510.7567.5

736.4

748.631.22

65.758.161.2

64.5

66.35.34

57.238.341.6

55.8

56.53.86

1.80.81.0

1.5

1.70.45

yields of sorghum in alternate hills with sun-flower and between rows of sunflower.

Effect on Yield and Yield Components of Sun-flower and Sorghum

Sunflower seed yield and yield components arepresented in Table 3. Intercropping signifi-cantly affected seed yield and yield compo-nents of sunflower. Seed yield per plant andper hectare were significantly higher in solesunflower, followed by the yields from sun-flower planted in five and three alternatingrows with sorghum respectively. The lowestyield was obtained in sunflower planted inalternate hills with sorghum. Similar trends ofresponse were shown for other yield compo-nents such as head diameter, seeds per head

and 1000-seed weight. For each seed yieldcomponents, the least was obtained from sun-flower planted in alternate hills with sorghum.Compared with sole sunflower, intercroppingsunflower in alternate hill and row with sor-ghum reduces sunflower's seed yield by 69.4and 44.4 % respectively.

In sorghum crop, grain yield componentswere also significantly affected by intercrop-ping (Table 4). The highest grain yields wereobtained from the sole sorghum. While yieldsfrom 3 and 5 alternating strips were not signifi-cantly different from that of sole sorghum^these were significantly higher than the yieldsobtained from sorghum planted in alternatehill and between single rows of sunflower.Compared to sole sorghum, grain yield per

Table 4. Effect of planting patterns on the yield and yield components of sorghum planted as sole crop or inmixtures with sunflower

Planting patternsof sorghum

Paniclelength(cm)

Paniclediameter

(cm)

Seeds/head

1000-seed Grain yield Grain yieldweight per plant per ha

(g) (g) (t/ha)

Sole cropAlternate hill with sunflowerBetween rows of sunflowerThree rows of sorghumalternating with 3 rowsof sunflowerFive rows of sorghumalternating with five rowsof sunflowerLSD (P 0.05)

26.517.319.1

17.114.215.6

189212001710

28.217.121.4

48.721.330.1

2.50.50.9

24.7

26.1

3.12

16.1

16.9

1.31

1874

188933.61

26.8

27.64.51

46.2

47.9

5.22

1.8

2.10.81

Intercro^pingSunflower with Sorghum 355

la e . Intluence of planting pattern of leaf area index and light transmission in intercropped sunflower andsorghum

Planting pattern

Light transmissison (%)

Light transmission

Sunflower Sorghum

Leaf area index

Sunflower Sorghum

Total Reduction Total Reduction

Sole sunflowerSole sorghumSunflower and sorghumin alternate hillsSunflower and sorghumin alternate rowsThree rows of sunflowerfollowed by three rowsof sorghumFive rows of sunflowerfollowed by five rowsof sorghum

79—

50

64

75

79

71

48

59

69

71

4.21

1.54

1.86

3.51

3.82

63.42

55.81

16.82

9.26

3.81

2.25

2.80

3.34

3.65

40.90

26.50

12.33

4.19

hectare in sorghum planted in alternate hill andin single alternating rows with sunflower weresignificantly reduced by 160 and 71 % respec-tively. All grain yield components followedsimilar pattern of response found for grainyields; the sole crop in each case havmg thehighest and those in alternate hills with sun-flower the least.

Fffect on LAI, Percentage Light Transmissionand LER

The percent light transmission and LAI areshown in Table 5. Generally, sorghum trans-mitted less light than sunflower. Percent trans-mission was considerably reduced when sun-flower and sorghum were intercropped in al-ternate hills and in single alternating rows. Solesunflower and sunflower planted in five alter-nating rows with sorghum gave the same lighttransmission of 79 %. When compared with

sole crop, the sunflower plants in alternate hillswith sorghum had the highest LAI reductionof 63.42 % followed by 55.81 % reductionfrom those planted in single alternating rowswith sorghum; while the LAI of those plantedm 3 and 5 alternating rows were reduced by16.82 and 9.26 % respectively. Similar patternof reductions in LAI were observed in sor-ghum crop.

The LERs indicate that planting sunflowerand sorghum in three and five alternating rowsmade better use of the land than could be madeby growing the two crops separately. Inter-cropping sunflower with sorghum in alternatehills highly reduced LER, whilst single rowintercropping of the crops gave LER similar tothat of sole crop (Table 6). In all plantingmethods, the yields of sunflower made greatercontribution to land useage gains (LER) thanthat of sorghum.

Table 6. Land equivalent ratio (LER) of sunflower-sorghum mixtures as affected by planting arrangement

Planting patterns

Relative yield

Sunflower Sorghum LER

Sole sunflowerSole sorghumSunflower and sorghum in alternate hillsSunflower and sorghum in alternate rowsThree rows of sunflower followed by three rows of sorghumFive rows of sunflower followed by five rows of sorghum

1.00 1.00

—0.440.550.830.94

1.000.200.360.690.80

—0.640.911.521.74

356 ADETUNJI

Discussion

In the sunflower-sorghum intercrop reportedin this study, there was a separation of at least15 days between the anthesis of sunflower andthe heading of sorghum. This difference in thetime of reproductive development is advan-tageous because the two crops did not come tothe stage of maximum demand for nutrient andmoisture, aerial space and light at the sametime. Where this occurred reduction in yieldhas been reported (ENYI 1973, FISHER 1977).Nevertheless, intercrop competition with sun-flower was injurious to sorghum especiallywhen intercropped in alternate hills in the same

row.In both crop species, almost all the growth

and development characters that are suscepti-ble to environmental variables were influencedby the various planting methods, whilenumber of days to 50 % flowering which isgenetically controlled was least affected. Ofthe planting patterns, five rows of sunflowerbetween five rows of sorghum resulted insuperior plant growth and development ofboth crops. The other arrangements mighthave reduced growth and development becauseof severe competition for nutrients, moistureand light escpecially when planted in alternatehills and in single alternating rows. The com-petition might have been less in the five rowinterplanting method. Similar observation wasreported by CROOKSTON and HILL (1979) andANDREWS (1972).

Growing both crops in three and five alter-nating rows enhanced yield and yield compo-nents of the crop species as compared to plant-ing in alternate hills and single alternatingrows. These observations further stressed theimportance of minimizing plant competition inintercropping (WAHUA and MILLER 1978). Plantcompetition could be minimized not only bychoosing compatible crops but also by usingappropriate planting patterns. Strip intercrop-ping of three and five rows of sunflower andsorghum as used in this study reduces thecompetition between sunflower and sorghum.The major agronomic importance of strip in-tercropping is the creation of more borderrows and, consequently more intercrop andless intracrop competition. This change in typeof competition may be detrimental or benefi-cial to one or both crops. In this case, it ismore beneficial to sunflower. The magnitude

of this benefit or loss varies with the widths ofthe intercrop strips — narrow strips havegreater effect and wide strips less effect. Thusthe best performance from both crops wereobtained from the widest strips of five alternat-ing rows of sunflower and sorghum.

Compared with sole crops, yields of bothcrops decreased as the two species were mixedmore thoroughly. Nonetheless, intercroppingreduced the yield of sorghum more than that ofsunflower. This may be attributed to the al-lelophatic effect of sunflower (RICE 1974) or tothe strong competitive ability of sunflower.Sunflower being drought tolerant like sorghumwas able to suppress sorghum yield not onlybecause of its early anthesis, but also due to itsdeep tap root system which extend to about2 m in well structural soil (NG'ANG'A 1988).This crop can therefore extract more moistureand nutrients from the deeper parts of the soilprofile than shallow fibrous rooted sorghum.

The highest reductions in LAI for sunflowerand sorghum were obtained when both cropswere interplanted in alternate hills. Similarly,light transmission was also lowest in this plant-ing pattern. These two factors, which are veryimportant components of photosynthetic ac-tivity of green plants would explain why thetotal yields of the two crops were lowest underthis planting pattern. In all interplantingmethods, the yields of each component crop inthe mixture was lower than that of the solecrop, but land productivity as indicated byLER and RY values was higher in the inter-crop. This contradicts the report of ROBINSON

(1984) that intercropping sunflower withmaize decreased land productivity. This maybe due to the hardy nature of sorghum whichmakes it more competitive than maize. How-ever, the possible effect of the choice of cul-tivars of the two crops in the intercroppingcould not be elucidated from this study andthis would be suitable objective for future re-search.

Zusammenfassung

Wachstum und Ertrage eines Mischanbausvon Sorghum und Sonnenblumen {Helkn-thus annuus L.) in semi-ariden Gebieten vonNigeria

Der Einflufi von fiinf Bestellungsformen aufdas Wachstum, den Ertrag und die Ertrags-

IntercroppingSunflower with Sorghum 357

komponenten eines Mischanbaus von Sonnen-blume und Sorghum wurde in den Jahren 1989/90 an der Universitat von Maiduguri, Nigeria,untersucht. Grundsatzlich ist festzustellen,dafi ein Mischanbau starker Sorghum als Son-nenblume beeintrachtigte. Sorghumpflanzen,die in alternierenden Horsten mit Sonnenblu-me angebaut wurden, hatten die kiirzestenSprofiachsen, die geringsten Trockenmassebil-dung und Gesamtsamenertrage/ha, wahrenddie hochsten Trockenmasse- und Samenertragevon Sorghum in einem Anbau mit fiinf alter-nierenden Reihen zusammen mit Sonnenblu-men erzielt werden konnten. Entsprechendwies Sonnenblume, in fiinf alternierenden Rei-hen zusammen mit Sorghum angebaut, diehochsten Ertrage im Vergleich mit anderenPflanzverfahren auf; es zeigten sich aber keinesignifikanten Differenzen in den Trockenmas-se- und Gesamtsamenertragen von Sorghumund Sonnenblume beim Anbau mit drei undfiinf alternierenden Reihen. Lichttransmission,Blattflachenindex und Ertrage beider Kultur-pflanzenarten folgten in den unterschiedlichenAnpflanzformen vergleichbaren Trends. EinMischanbau mit fiinf alternierenden Reihen er-gab die grol^te Blattflache und zeigte die ge-ringste Lichttransmission bei hochsten Ertra-gen. Die Landnutzungseffizienz wurde deut-lich um 52 % bzw. 74 % verbessert beim An-bau mit drei bzw. fiinf Reihen Pflanzformen.

References

ADO, S. G., and B. TANIMU, 1988: Sunflower(Helianthus annuus L.) germplasm introduction atSamaru, Nigeria. Germplasm Newsletter, Plant

Genetic Resource Centre/Ethopia and InternationalLivestock Center for Africa 17, 15—16.

ANDREWS, D . J., 1972: Intercropping with sorghumin Nigeria. Experimental Agriculture 8, 139—150.

BAKER, E. F. L, 1980: Mixed cropping in northernNigeria IV. Extended trials with cereal and ground-nuts. Experimental Agriculture 16, 361—369.

CROOKSTON, R. K., and D. S. HiLL, 1979: Grainyields and land equivalent ratios from intercrop-ping corn and soyabeans in Minnesota. AgronomyJournal 71, 41—44.

ENYI, B. A. C , 1973: Effects of intercropping maizeor sorghum with cowpea, pigeon peas or beans.Experimental Agriculture 9, 83—90.

FISHER, N . M., 1977: Studies in mixed cropping.IL Population pressures in maize-bean mixture.Experimental Agriculture 13, 185—191.

LITTLE, T. M., and F. J. HILLS, 1975: StatisticalMethods in Agricultural Research. Publication ofUniversity of California, Davis, USA.

MBIZA, A. B. C , 1988: Sunflower Production:Problems and Research Progress in Tanzania. In:Proceeding of the Fourth Oil Crops NetworkWorkshop, Hjoro, Kenya, 25th—29th January,1988, p. 123—129.

NG'ANG'A, C , 1988: Growing sunflower for oilcrop development. In: Proceeding of the FourthOil Crops Network Workshop, Njoro, Kenya,25th—29th January, 1988, p. 123—129.

RICE, E. L., 1974: Allelopathy. Academic Press,New York, p. 41—48.

ROBINSON, R. G., 1984: Sunflower for strip, rowand relay intercropping. Agronomy Journal 76 (1),4 3 ^ 7 .

United States Department of Agriculture (USDA),1975: Soul Taxonomy: A basic system of soil clas-sification for marking, interpreting soil surveys.USDA Agricultural Handbook No. 436.

WAHUA, T. A. T., and D. A. MiLLER, 1978: Relativeyield totals and yield components of intercroppedsorghum and soyabean. Agronomy Journal 70 (2),287—291.