Gross margin analysis of rubber based cropping systems in Nigeria

The study aims at determining the economic impact of the rubber based cropping system introduced to rubber farmers in Nigeria by Rubber Research Institute of Nigeria under the sponsorship of the Common Fund for Commodity (CFC) project in Nigeria coded CFC-IRSG 21. Thirty three farmers were randomly selected in five states in Nigeria (Edo, Delta, Ogun, Kaduna and Akwa Ibom) using interview schedule. The profitability of rubber based cropping systems on farmers’ farms in the five states was determined using gross margin analysis. The study revealed that rubber based cropping systems in the study area were profitable with positive gross margins for all the identified cropping systems in the study area. Furthermore, the study revealed that a gross margin of N178, 000/ha and return on investment of N4.79 was the highest for the two cropping system identified in Edo state. A gross margin of N331, 000/ha and return on investment of N7.76 per Naira was the highest for the three cropping system adopted in Delta state. For the four crop combination in Ogun state, a gross margin of N181,000 and return on investment of N6.32 per Naira was the highest. In Akwa Ibom state, a gross margin of N402, 100 and return on investment of N8.05 per Naira was the highest for the three crop combination. For the four crop combination in Kaduna state, gross margin of N 488,000 was the highest. The study however, concluded that cassava featured more in the intercropped combination and it gave higher gross returns in the rubber based cropping systems in Nigeria compared with other crops across the states.


INTRODUCTION
Rubber industry in Nigeria suffered significant decline by almost 50% in the past two decades (NRAN, 2014).Some of the reasons for the decline include; demand for large expanse of land and almost 70% of the vast interrow spaces are underutilized.Secondly, long gestation period of the crop (about 5 to 7 years), a period during which the rubber plantation cannot be tapped for latex and hence no income accrued from the huge capital investment and maintenance of the plantation.This situation has remained a disincentive to rubber farmers and has made rubber enterprise unattractive, especially to small-scaled farmers in Nigeria.
One possible approach that may assist smallholder rubber farmers is to create a source of income capable of back rolling the cost of plantation maintenance, take care of his family food needs and other personal expenses.Hence, a timely adoption of appropriate plantation management practices that is capable of utilizing the under-utilized land resources and increases the revenue base of the enterprises is important to the attainment of the drive for increase rubber production in Nigeria.
Intercropping of rubber with arable crops has been found to be beneficial to the growth of rubber and capable of improving the economy of the rubber enterprise thereby reducing the need for subsidies and credit to rubber farmers (Zainol et al., 1993, Haliru et al., 2014).Many researchers have demonstrated that intercropping of rubber with arable crop is advantageous in boosting yield crops (Masea and Cramp, 1995).It has also been reported that intercropping of rubber increase the rate of growth of rubber thereby reducing the gestation period of rubber (Esekhade and Idoko, 2009).Rubber Research Institute of Nigeria through the project 'Promote economically viable small holding rubber production in West Africa' funded by the Common Fund for Commodity (CFC) and the International Rubber Study Group (IRSG) have encouraged several farmers in Nigeria to go into rubber farming and intercropped their plantations with arable and bi-annual crops during the immature phase.Surveys have established, however, that rubber smallholders are practising intercropping (Mesike et al., 2009;Uzokwe U.N., 2009).The component food crops recommended to smallholder farmers as intercrop with rubber in Nigeria are maize, soybean, pepper, cowpea, tomato, yam, or cassava (Rosyid et al, 2008).This system has been reported to improve the soil (Masea and Cramp, 1995), enhance the growth rates of rubber (Abdul Razak and Barizan, 2001), increase land productivity, and reduce cost of plantation management by ensuring early income generation to farmer during the period of immaturity (Abraham, 1980;Zainol et al., 1993).Despite these positive benefits of rubber based intercropping system, there are still pockets of scepticism by some farmers in adopting this technology.Hence, there is need for a research to quantify in monetary terms, the derivable gains in adopting the system.Hence, this study was carried out to determine the actual economic benefit of different arable crops and their combinations as intercrop with rubber in Nigeria.

MATERIALS AND METHODS
The study was conducted in 5 states in Nigeria which include; Delta, Edo, Ogun, Akwa Ibom and Kaduna state.Rubber plantations were established using the doubled row planting system at a spacing of 2.5 x 2.5 m and 10 m avenue between each double row of rubber.The component crops were planted in the inter rows at a spacing of at least 1.0 m away from the rubber.Component crop spacing was the recommended spacing for each crop.Based on soil test results, fertilizer were applied (uniform broadcast) at the rate of 19.0, 60.0, 36.0 and 5.0 kg ha -1 N, P 2 O 5 , K 2 O and MgO; using urea, single super phosphate, muriate of potash and magnesium sulphate as sources respectively.The fertilizers were divided into two equal doses and applied at planting and 3 months after planting.All farmers were encouraged to observe all agronomic protocols up to harvesting, processing and marketing.Data were generated using the primary data collected through personal interview schedule and structured questionnaires administered to the beneficiaries of CFC-IRSG 21 project in Nigeria.Altogether, 33 respondents were randomly selected across the states (Table 1).The major economic activity of the respondents is farming.The major crops cultivated are rubber, cassava, yam, maize, plantain, cassava, pineapple, watermelon, cocoyam and different types of vegetables.A whole farm budgetary technique was used to assess the profitability of rubber-based cropping systems among the beneficiaries of the project.The farmers made use of traditional farm implements like hoes, cutlasses with negligible depreciation.The profitability of the farm was determined using gross margin analysis as follows: Gross Margin = Total Revenue -Total Variable cost Where Total Revenue (TR), TR= P Variable costs include cost of labour, fertilizer, chemicals and other variable inputs.Returns per Naira (₦) invested (RI) was computed as RI= Gross Returns/TVC.The higher the value of RI the more profitable is the cropping system.

RESULTS AND DISCUSSION
The total variable cost per hectare for each cropping system is shown in Table 2.There are many intercropped combinations with rubber but the major crops intercropped with rubber include cassava, yam, maize, plantain, pineapple, watermelon, melon and millet.Labour costs incurred by farmers for the cropping systems were due to land preparation, planting, weeding,  fertilizer applications and harvesting.Labour cost was the highest variable cost incurred and it accounted for over 40% of the total variable cost in Edo, Delta, Akwa Ibom and Kaduna states.The farmers used 2 to 4 L of herbicides per hectare with an average of 3 L per hectare.The cost of herbicides used was estimated at ₦3, 000 per hectare.The price of 1 bag of fertilizer ranged from ₦4, 500 to ₦5, 500 for 50 kg bag with an average of ₦5, 000 per bag.Fertilizer cost was about ₦15, 000 per hectare.Farm returns for the rubber based cropping system in each state are shown in Tables 3 to 7. The gross returns were calculated by multiplying the total quantity of the outputs by the average market price prevailing at the period.The study revealed that cassava has the highest return per hectare when compared with other crops that were intercropped with rubber in Edo, Delta and Ogun states.However, coco yam and maize have the highest return in Akwa Ibom and Kaduna respectively.Data in Table 3 shows that the two cropping systems adopted by farmers in Edo state recorded gross returns of ₦225,000 per hectare.In Table 4, the combination of rubbercassava-plantain-pineapple intercropping gave the highest gross returns of ₦380,000 per hectare in Delta state when compared to other cropping systems adopted in the state.In ogun state, rubber-maize-water melon  cropping system gave the highest gross returns of ₦215,800 per hectare when compared to other cropping systems in the area (Table 5).From the results in Table 6 and 7, rubber-cassava-telfera-cocoyam and rubbercassava-yam-melon-maize-rice cropping system have the highest gross return of ₦459,000 and ₦550,000 per hectare respectively in Akwa Ibom and Kaduna state when compared with other cropping system in the states.
Table 8 shows that farmers make positive Gross Margin for the various types of cropping systems in the study area.For the cropping system used in Edo state, the combination of rubber-cassava-plantain-maize cropping system consistently gave higher gross margin (₦178, 000/ha) and return on investment of ₦4.79 than the combination of rubber-cassava-yam-maize.The value of the return on investment indicated that for every ₦1 invested in the cropping combination, there was a return of ₦4.79.For Delta state, the intercropping of rubbercassava-plantain-pineapple gave the highest gross margin (₦331, 000/ha) and return on investment (₦7.76) in the three cropping system used by the farmers.For the cropping combination in Ogun state, the intercropping of rubber-maize-watermelon consistently gave the highest gross margin of ₦181,000 and return on investment of ₦6.32.For the cropping combination used in Akwa Ibom state, the intercropping of rubber/cassava/telfera/    cocoyam also consistently gave the highest gross margin of ₦402,100 and return on investment of ₦8.05.For the cropping combination used in Kaduna state, the intercropping of rubber-cassava-yam-melon-maize-rice have the highest gross margin of ₦488,000.However, the return on investment of ₦8.87 for cassava-yammelon-maize-rice intercrop was not the highest in Kaduna state because of high labour cost recorded in the crop combination.However, the highest return on investment in Kaduna state was obtained from intercropped rubbermaize-millet-bitter leaf-pepper (₦9.76).

CONCLUSION AND RECOMMENDATIONS
The study shows that farmers in the study area used different crops like cassava, yam, maize, plantain, pineapple, millet, leafy and fruity vegetables for intercropping with rubber.The farmers made positive returns on capital invested for different combination of cropping systems used in the study area.Generally, cassava featured more in the intercropped combination and it gave higher gross returns in the rubber based cropping systems in Nigeria compared with other crops across the states.In Edo and Delta State, cropping systems involving cassava and plantain gave the highest gross returns while in Ogun state it was maize and water melon.In Kaduna state, it was the cassava, yam, melon, maize while in Akwa Ibom it was cassava, telfria and cocoyam combinations.

Table 1 .
Distribution of selected farmers by state.

Table 2 .
Total variable cost and relative input cost per hectare.

Table 3 .
Gross returns per hectare of rubber-based cropping system in Edo state.

Table 4 .
Gross returns per hectare of rubber-based cropping system in Delta state.

Table 5 .
Gross returns per hectare of rubber-based cropping system in Ogun state.

Table 6 .
Gross returns per hectare of rubber-based cropping system in Akwa Ibom state.

Table 7 .
Gross returns per hectare of rubber-based cropping system in Kaduna state.

Table 8 .
Gross Margins and Returns per Naira invested per hectare of rubber-based cropping system.