ISSN 2277-0836; Volume 1, Issue 6, pp. 97-101; September, 2012.

Journal of Agriculture and Biodiversity Research ©2012 Online Research Journals Full Length Research Available Online at http://www.onlineresearchjournals.org/JABR

Rubber, Maize and Cassava Intercropping Systems on Rehabilitated Rubber Plantation Soil in South Eastern Nigeria Idoko SO1*, Ehigiator JO2, Esekhade TU1, Orimoloye JR1 1

2

Rubber Research Institute of Nigeria, Benin City, Edo State, Nigeria. Department of Soil Science, University of Benin, Benin City, Edo State, Nigeria.

Download 7 August, 2012

Accepted 15 September, 2012

This study was conducted to determine the effects of old rubber plantation soil on the performances of rubber, maize and cassava intercropping systems. The study was carried out at Iyanomo, Benin City, Edo State. The trial was conducted on a plot of one hectare adopted from the 45 years old plantation at Iyanomo. The treatments comprised of seven treatments (Control, Sole rubber, Sole maize, Sole cassava, Rubber + maize, Rubber + cassava, Rubber + maize + cassava) arranged in a Randomized Complete Block Design (RCBD) with each treatment replicated three times. Data were generated on the soil, growth characteristics and yield of the crops. The data collected were subjected to analysis of variance statistics and significant means were separated using the Duncan Multiple Range Test. The result indicated no significant effect of intercropping on the morphological characteristics and yield of maize and cassava. But rubber morphological growth and biomass yield were significantly reduced by intercropping with maize and cassava. However, intercropping of rubber with maize and cassava on rehabilitated land showed greater agronomic advantage compared with sole cropping of rubber, maize or cassava, as indicated by the Land Equivalent Ratio values greater than one (1.73 for Rubber + Maize; 1.59 for Rubber + Cassava and 2.42 for Rubber + Maize + Cassava systems). Hence, it can be concluded that it is possible to utilize rehabilitated rubber plantation land for rubber replanting and intercropping with maize and cassava, but more economic advantage was derived from intercropping rubber with maize and cassava. Keywords: Rubber plantation, intercropping systems, agronomic advantage, maize, cassava, Nigeria.

INTRODUCTION Nigeria has recorded a decline in natural rubber plantation since the late 1960s [1,2]. This has been attributed to poor plantation management, unstable market prices, over dependence on petroleum revenue and lack of access to farm credit which made many local farmers to pay less attention to their plantations. The resulting effect of which was low latex yields and eventual abandoning of the old plantations as revenue declined. However, the recent increases in the price of natural rubber due to higher demand in the international market and the need for Nigeria to diversify her sources of revenue and create employment for the restive youth *

Corresponding Author’s Email: [email protected].

especially in the Niger Delta which coincide with the rubber belt of Nigeria, make it imperative to increase rubber production in Nigeria and the convenient place to start is the restoration of the substantial old and abandoned rubber plantations in the country. More than 70% of rubber production in Nigeria is still produced by small scale rubber farmers who usually practice intercropping in their plantation especially before canopy closure [3,4]. Intercropping various crops during the immature stage of rubber provides alternative sources of income to smallholder farmers and other agronomic benefits [5-8]. Hence, efforts aimed at attracting smallholder farmers back to rubber plantation by replanting old plantation must focus on the effective land utilization systems as practiced by farmers in the

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local environment. Hence this work was carried out to determine effect of intercropping rubber, maize and cassava after rubber land rehabilitation on the development and yield of rubber, maize and cassava, leading to the determination of a better agronomic option for the utilization of land cleared from old rubber plantation.

MATERIALS AND METHODS This study was carried out at Iyanomo near Benin City, o o Edo State, located between longitude (5 35’ and 5 55’E) o o and latitude (6 05’ and 6 25’N). The climate of the area is humid tropical, with dominant rainy and a less influencing dry season alternating annually. The soil is characterized by deep, porous sandy to loamy sand surface soils overlying sandy loam to sandy clay sub soil. Soil reaction is usually strongly acidic to very strongly acidic with very low base status and cation exchange capacities (CEC) [9]. The old age plantation was opened up from natural forest in 1960 with no history of fertilizer application for about 20 years before the commencement of the experiment. The land use before commencement of rubber was several cycles of arable cropping under a bush fallow system, alternating 3 years of cropping and 5 – 7 years of bush fallow system. One hectare (1ha) land was adopted from the old plantation planted with GT I clone. The plot was cleared by falling the rubber trees using motor-saw, while the under growth and stumps were manually cleared to minimize soil disturbances. The experiment comprising seven (7) treatments arranged in a Randomized Complete Block Design with each treatment replicated three times. Each plot measured 10m x 8m with 2m between each blocks, plots and borders. The treatments were; Control (No cropping or fallow), Sole rubber (5.2 x 3.2m spacing i.e. 601 plants/ha), Sole maize (90 x 30cm spacing i.e. 18, 500 plants/ha), Sole cassava (100 x 100cm spacing i.e. 10,000plants/ha), Rubber + maize, Rubber + cassava, Rubber + maize + cassava. The cropping intensities in the intercrops based on individual sole crop population were; rubber + maize (100% rubber and maize 83%), rubber + cassava (100% rubber and cassava 60%) while in the rubber + maize + cassava (100% rubber, maize 45.5% and cassava 50%). GT I clone rubber budded stumps; IITA 92/0057 (cassava) and Acr.97 TZL Comp. 1-W (late-maturing) (maize) varieties were used for the experiment. Data were generated on some soil physical and chemical characteristics, physiological growth characteristics of the crops and yields of maize and cassava were collected at maturity. While the biomass yield of rubber was taken in lieu of the yield of rubber because they did not mature at the end of the cropping season. Data were subjected to the F-ratio test [10].

Significant means were separated using the DMRT.

RESULTS AND DISCUSSIONS The results of the effect of rubber based cropping systems on rehabilitated rubber plantation on the physico-chemical properties of the soil are presented in Table 1. There was no significant effect of intercropping on the particle size distribution (percentage sand, silt and clay) and pH (H2O) of the soil. However, generally, the pH of the soil in all the treatments increases from the precropping value, except for R + C and R + M systems. Kang [11] reported that, this was as a result of continuous cultivation in intercropping systems. The increases in the pH values in sole systems compared with the intercropping systems, demonstrates that intercropping lead to reduction in soil acidity compared with sole cropping, because of higher organic material generation. This is consistence with the submission of [6,7] who observed higher pH in soil under intercropping compared with soil under sole cropping. The lower pH values in the R + C intercropping system, may be attributed to the longer duration of crop interactions in R + C compared to R + M. While the higher pH values in R + M + C systems compared to the R + M and R + C, can be attributed to the higher level of organic matter production. Yasin et al., [12] argued that, decomposition product of organic matter (maize) in the soil can play a role as soil pH regulator. The concentration of exchangeable bases increases above the pre cropping values except in Mg where there was a decline R+C treatment due to cassava. This is attributable to the effect of removal of vegetation involving clearing burning during land preparation which triggers the breakdown of organic matter and nutrient mineralization. Nye and Greenland [13] reported that continuous land cultivation leads to nutrient mineralization and nutrient release in the soil. The result showed a significant effect of intercropping on the organic carbon concentration in the soil. The sole cassava and sole rubber treatments showed significantly higher organic concentrations compared with the other treatments due to higher Litter production and residue addition under the cropping systems involving cassava leading to increase in organic carbon content in the soil. Furthermore, compared with the control, all the treatments recorded higher organic carbon concentration except R+C and R+M+C treatments. This result is similar to the study of earlier results of intercropping studies with cassava [7]. Nitrogen concentrations were not significantly affected by intercropping, but the concentrations in all the treatments were generally low. This is because the soils of the area is an ultisols, characterized by high acidity, low nutrient status and low activity clay and are subjected to rapid fertility decline on land clearing for cultivation [14]. The available P concentrations recorded after first year of cropping were not significant and were generally

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Table 1. Effects of rubber cropping systems on rehabilitated rubber soil on some Physico-chemical Properties of the Soil.

Treatment

Control SR SM SC R+M R+C R+M+C

Sand %

84.20 83.53 84.53 87.20 85.20 83.20 84.87

Silt %

3.80 4.14 3.80 2.47 0.80 2.80 1.13

Clay %

12.0 12.33 11.67 10.33 14.00 12.17 14.00

Textural Class

LS LS LS LS LS LS LS

pH (H20)

5.20 5.23 5.23 5.33 5.10 4.97 5.33

Org. C -1 g kg soil

N g -1 kg soil

P mg -1 kg

Ca

Mg

13.7ab 16.8a 13.7ab 17.4a 13.9ab 13.2ab 11.5b

0.33 0.41 0.36 0.42 0.36 0.33 0.30

25.65 27.11 29.41 25.65 24.17 27.56 26.59

0.28ab 0.28ab 0.20b 0.36a 0.18b 0.23ab 0.30ab

0.17 0.22 0.18 0.21 0.41 0.16 0.17

Na

K

0.42 0.44 0.43 0.44 0.43 0.43 0.43

cmol -1 kg Soil 0.19 0.18 0.11 0.16 0.13 0.13 0.12

Exch. Acidity

ECEC

BS

Zn

Cu

Fe

Mn

169.67 136.67 159.00 124.90 140.70 139.33 122.37

7.93 10.13 13.23 9.23 10.00 14.47 14.57

mg -1 kg 0.73 0.93 0.93 0.87 0.87 0.80 0.93

1.73 2.08 1.85 2.04 1.76 1.74 1.96

58.13 55.23 49.66 57.44 50.88 53.85 52.47

1.30 1.34 1.05 0.81 1.03 0.88 1.22

1.16 1.26 1.29 1.24 1.20 1.29 1.39

SR=Sole Rubber, SC=Sole Cassava, SM=Sole Maize, R+M=Rubber + Maize, R+C= Rubber + Cassava, R+M+C=Rubber + Maize + Cassava, LS= Loamy Sand Means in a column followed by the same alphabets are not significantly different.

Table 2. Effect of intercropping on rehabilitated rubber plantation soil on the growth characteristics of maize.

Treatment So-Ma Ru + Ma Ru+Ma+Ca

Height (cm) 86.53 88.40 91.31

Girth (cm) 0.88 0.93 0.70

No. of Leaves 8 8 8

2

Leaf Area (cm ) 184.74 183.43 173.61

Means in a column followed by the same alphabets are not significantly different.

Table 3. Effect of intercropping on rehabilitated rubber plantation soil on the growth characteristics of cassava.

Treatment So-Ca Ru + Ca Ru+Ma+Ca

Height (cm) 111.84 106.33 129.02

Girth (cm) 1.57 1.53 1.87

2

Leaf Area (cm ) 184.74 183.43 173.61

Means in a column followed by the same alphabets are not significantly different.

high and did not follow any particular pattern. The results of the heavy metals (Zn, Cu, Fe and Mn) were not statistically significant. The results of

intercropping on rehabilitated rubber soil on the morphology of crops are presented in Tables 2-4. There were no significant effect of intercropping

on the morphological growth characteristics (plant height, stem girth, number of leaves and leaf area) of maize and cassava. This was because of

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Table 4. Effect of intercropping on old rubber plantation soil on the growth characteristics of rubber.

Treatment So-Ru Ru + Ma Ru + Ca Ru+Ma+Ca

Height (cm) 49.13 41.74 35.89 30.28

Girth (cm) 0.81 0.78 0.74 0.66

No. of Leaves 15 13 11 10

2

Leaf Area (cm ) 33.79 33.31 36.21 29.80

Means in a column followed by the same alphabets are not significantly different.

Table 5. Effect of intercropping on old rubber plantation soil of the yields of rubber, maize and cassava (Tones/ha).

Treatments SR SM SC R+M R+C R+M+C

Rubber a 0.011 a 0.076 a 0.008 b 0.004

Maize 1.573 1.571 1.388

Cassava 20.19 21.90 14.10

LER 1 1 1 1.69 1.78 1.90

Means in a column followed by the same alphabets are not significantly different.

minimal competition for resources due to the short duration of maize crop and the rubber were too young to compete with cassava. This is similar to the report of [7] who observed no significant effect of intercropping on the growth characteristics of cassava and maize when intercropped with rubber. However, the morphological growth characteristics of rubber were significantly affected by intercropping with maize and cassava (Table 4). Intercropping rubber reduced the morphological growth characteristics of rubber especially in systems involving cassava. The reduction can be attributable to competition of cassava as earlier reported by [6,14]. They concluded that, nature of crops or crop combinations and the duration of association in a cropping system play significant role in the growth and development of rubber saplings. The yield of rubber, maize, cassava and LER analysis are presented in Table 5. The rubber biomass yield was higher in the sole crop treatments compared with that of the intercropped treatments, with the R+M+C treatments producing significantly lower biomass compared with those the sole, R+M and R+C treatments. This is attributed to the negative effect of cassava on the performance of rubber which is in agreement with the submission of [6,15]. The depression of rubber growth is attributed to competition for resources between rubber and cassava. The yields of maize and cassava were not significantly affected by intercropping with rubber and cassava. The result Land Equivalent Ratio (LER) of the cropping systems showed that all the intercropping systems (R+M, R+C and R+M+C) recorded LER values above one, indicating greater advantage of intercropping

over sole cropping. The highest LER values were recorded in the R + M + C intercropping systems followed by R+C and R+ Maize respectively. This result is in agreement with the submission of other workers in the intercropping trials who recorded LER values greater than one, in rubber based intercropping systems [16-19]. CONCLUSION It is possible to utilize the land cleared from old rubber plantation for replacement with rubber, maize and cassava; the land can also support intercropping systems of rubber with maize and cassava. But, the results showed that it is more advantageous to practice multiple crops intercropping systems with rubber (rubber + maize + cassava) compared with planting rubber, maize and cassava as sole crops. Though the soil analysis results revealed adequacies of most of the critical nutrients, but since there was depression in vegetative growth of rubber due to competition especially from cassava, It is advisable that, all intercropping systems especially those involving cassava must be accompanied with adequate fertilizer regimes to ensure optimum growth of rubber. Acknowledgement The authors wish to thank the Executive Director (RRIN), Professor O.I. Eguavoen and the Head of Soil Science Department, University of Benin, Benin city, (Dr ER. Orueh) for providing the enabling environment for this

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study.

[17] Yunusa IAM. Effect of planting densities and plant arrangement pattern on growth and yield of maize and soya bean in mixtures. J. Agric. Sci. Camp., 1989; 112: 1-8.

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