Indonesian Rubber Research Institute

Abstract

Natural rubber is one of the more important commodities in Indonesia and is a source of both foreign exchange and also income for more than twelve million people who depend on the rubber industry for their livelihood. The rubber planters in Indonesia are predominately smallholders and therefore the quantity and quality of Indonesian rubber depends mainly on the conditions used by these rubber smallholders. As a result of the their low productivity (less than 1000kg drc/ha), smallholder income, national production and foreign exchange earnings are also low. Hence, it is essential that the productivity of smallholders is improved through improvements in the technology of their farming systems.

Sembawa Research Station has utilized three steps in the development of rubber based farming systems:

1. By providing recommended planting materials through farmer groups;

2. By developing a technological package of intercropping during immature periods;

3. By investigating the optimum scale for rubber based farming systems.

The results showed that farmers can gain cheaper planting material (clones PR 261 and BPM 24) through farmer groups of 10 - 15 farmers. Both food and horticulture crops could be intercropped between immature rubber with no effect on rubber growth.

The optimum rubber-based farming systems can be achieved by planting 1.4 ha of rubber (PR 261), 0.5ha of food crops and rearing 3.0 cattle. This farming system needs 630 man days/year and generates an income of Rp 4,751,291.-/year (US$2000/year).

Introduction

Natural rubber is one of the more important commodities in Indonesia, a source of both foreign exchange and also of cash income for more than twelve million people who depend on the rubber industry for their livelihood. Rubber planters in Indonesia are predominately smallholders (84%) and so the quality and quantity of Indonesian rubber depends mainly on the conditions used by rubber smallholders.

Average smallholder rubber production is very low at present, ie only 670 kg/ha/year1. There are two main causal factors for the conditions used, as follows:

1. Most farmers use traditional technology, unselected seedlings, no soil conservation, low fertilizer input, low plant maintenance, high planting density (> 500 trees/ha) and over-tapping;

2. The red-yellow podzolic (ultisol) land used for rubber development areas in Indonesiais of low fertility.

These conditions influence smallholder income, national production and foreign exchange earnings.

The Government effort to improve the conditions used by smallholders has been carried out by developing a smallholder rubber project. Nevertheless, this development project covered only 14% of the total rubber area in Indonesia with the result that 86% of the area still needs to be improved. Hence, it is still essential to increase the productivity of smallholder through improvements in the technology of their farming systems.

Sembawa Research Station has defined three steps for the development of rubber based farming systems:

i. The provision of recommended planting materials through farmer groups;

ii. The development of a technological intercropping package for use during the immature period;

iii.The investigation of the optimum scale for rubber based farming systems.

Provision of planting material

Most Indonesian smallholders used seedlings as planting material although they were aware that there were many disadvantages for rubber productivity. General problems faced by farmers include lack of knowledge in addition to capital constraints on the buying of recommended planting materials.

An alternative means of providing low cost and available clonal planting materials is the establishment of budwood gardens (recommended clones being PR 261 and BPM 24) and rootstock nurseries at the farmer level operated by "farmer groups", each group consisting of 10 to 15 farmers. The budwood gardens and the rootstock nurseries are 0.1 and 0.25ha respectively in size. A self-assistance programme on the preparation of planting materials is given to the group to help in the improvement of farmer' expertise.

The revolving systems has been used, where the first budget came from government. From these programmes, the farmers belonging to the groups buy planting material (one whorl polybags) at a subsidized price and the payments collected are continually used for new nursery establishment in the following year. Compared to the price of planting materials from Sembawa Research Station (US$0.35/plant), the price of that produced by farmer groups was much cheaper (US$0.075/plant)

Sembawa Research Station has implemented these programmes at 10 villages in South Sumatra and Jambi Province. These programmes were originally developed by financing smallholders in 154 villages in South Sumatra and 295 villages in Jambi Province. The direct benefits of these programmes2 included:

a. To stimulate farmers to plant clonal planting material;

b. To provide low cost planting materials which are available at the village level;

c. To train farmers to increase their capability to produce their own clonal planting materials. These programmes need very intensive guidance from local agricultural extensionists in all steps, from nursery preparation to grafting and transplanting to the field.

Field extensionists should be motivated to assist farmers in their working area, especially by providing transportation facilities so they can reach their scattered and remote working areas. Site selection and coordinated guidance by the institutions involved are critical points for the success of these programmes.

Intercropping between immature rubber

Smallholder rubber plantations usually have spacings of 7 × 3m or 6 × 3m. This is wide enough for intercropping for at least the first 3 years of the immature period. Intercrops serve a double function. Besides giving farmers additional income and increasing land and labour productivity, they also acts as cover crops which can reduce soil erosion.

Sembawa Research Station has conducted research on food crops cropping patterns and horticulture as intercrops between rubber trees in order to increase land productivity and soil conservation in smallholder rubber areas.

Food crops cropping patterns as rubber intercrops

The recommended food crop cropping pattern which has been developed and is practised in South Sumatra Province as rubber intercrops is corn + upland rice - soybean - cowpea. Intercrops are planted about 100cm from rubber trees (Figures 1 and 2). The alternative food crop varieties, spacing, seed used and fertilizer needs are shown in Table 1.

Research on this cropping pattern showed that yields met with were sufficiently good enough to satisfy the subsistence needs of the farmer (Table 2). The annual food requirement per capita is about 1812cal, equivalent to 320kgs of rice per year3. Hence, food crops, as rubber intercrops, can be continued for three years and these intercrops would still be profitable until the end of the three year period insofar as net income is concerned. The development of the roots and canopy of the rubber trees will limit the productivity of the intercrops in the fourth and later years.

  Table 1 Alternative food crop varieties, spacing, seed used and fertilizer needs for food crops cropping pattern as a rubber intercrop

Crop	Spacing (cm)	Seed use (kg/ha)	Fertilizer (kg/ha)				Varieties
			Urea	TSP	KCl	Lime
Corn Upland rice Soybean Cowpea	200 × 50cm 40 × 10cm 40 × 10cm 30 × 20cm	12 30 20 20	75 100 50 50	75 125 75 50	25 50 50 50	- - 200 200	Arjuna Way rarem Wilis Local

Table 2 Yield and net income of food crops cropping patterns as rubber intercrops

Crop	First year			Second year			Third year
	Yield (kg/ha)	Cal (kg/ha)	Protein (kg/ha)	Yield (kg/ha)	Cal (kg/ha)	Protein (kg/ha)	Yield (kg/ha)	Cal (kg/ha)	Protein (kg/ha)
Corn Upland rice Soybean Cowpea	1500 1900 1100 1250	5100 6856 3685 3375	152 148 209 180	1200 1750 950 1200	4080 6315 3183 3240	121 137 181 173	900 1200 750 615	3060 4330 2513 1661	91 94 143 89
Total	-	19,016	689	-	16,818	612	-	11,564	417
Revenue(US$) Capital(US$) Income (US$)	1350 950 400			1200 850 350			900 700 200

The food crops cropping pattern as rubber intercrops has a positive effect on rubber growth, due to the residue of the fertilizer given to the food crops, good tillage between the rubber trees, and also because soybean and cowpea increases nitrogen levels in the soil. Hence, the soil conditions with food intercrops are better than with other intercrops, such as leguminous cover crops (LCC) and forage for which tillage and fertilizer are only done once. Fertilizer dosage for the last cropping systems is 25 kg/ha urea and 25 kg/ha TSP per year.

These intercrops have a better effect on rubber growth (Table 3) as indicated by stem diameter and the number of whorls compared to the effect of leguminous cover crops and forage. These results are similar to those obtained by Chandresekera⁴.

Table 3 Effect of different kinds of intercrop on the stem diameter and number of whorls of rubber after 12 months

Intercrop	Stem diameter (mm)	Number of whorls
Food crops cropping pattern Pueraria javanica Mucuna cochinchinensis Calapogonium mucunoides Centrosema plumeri Centrosema pubescens Forage (Setaria sp)	23.5 18.8 22.3 22.9 22.6 22.1 21.0	5.9 4.6 5.3 5.1 5.4 5.1 5.3

Horticulture as a rubber intercrop

Horticulture is usually used for intercrops by farmers who want cash income but also have land sited near to the market. Some horticulture, usually used by farmers in South Sumatra Province, is as follows:

a. Pineapple + banana.

b. Chilli.

The alternative crops, spacing, seed used and fertilizer needed are shown in Table 4.

Table 4 Alternative crops, spacing, seed (planting material) used and fertilizer need

Crop	Spacing	Seed or planting material	Fertilizer (kg/ha)
			Urea		TSP		KCl		Organic matter
			1st year	2nd year	1st year	2nd year	1st year	2nd year
Pineapple+ banana Banana Pineapple Chilli	7 × 3m 60 × 50cm 80 × 60cm	476 * 24000 * 50 gr	475 150 150	570 300 -	190 90 150	380 180 -	285 75 100	380 150 -	- - 6000

Research results showed that a suitable yield could be achieved from pineapple and banana from a one hectare area of rubber if practised for four years (Table 5). This pattern also caused no negative effect on rubber growth which was comparable (Table 6). This result is similar to those obtained by Kaewbamroong⁵.

The yield of chilli as a rubber intercrop is given in Table 7. Chilli generated the highest income for farmers. Chilli has a good market in Indonesia where it is an important food ingredient. Furthermore, this crop needs very high organic matter so it could improve the quality of the soil structure. Chilli could be practised as a rubber intercrop for a three year period (Table 8). This crop also caused no negative effect on rubber growth and, conversely, promoted growth because there was better tillage and an improvement in soil structure and fertility.

All of these intercrops could increase land productivity and farmer income as well as promoting rubber growth.

Table 5 Yield of pineapple + banana as rubber intercrops

Items	Yields
	First year	Second year	Third year	Fourth year
Banana	100	300	400	375
Pineapple	7000	18,000	20,000	24,000
Revenue (US$)	400	1000	1200	1300
Capital (US$)	800	500	500	550
Income (US$)	-400	500	700	750

Table 6 Effect of pineapple + banana as intercrops on girth of rubber (42 months)

Crop	Girth(cm)
Without intercop	20.9
Pineapple+Banana	21.6

Table 7 Financial analysis of chilli as a rubber intercrop (36 months)

Items	Value
Yield of chilli (kg/ha)	7095
Revenue (US$)	3850
Capital (US$)	750
Income (US$)	3100

Table 8 Effect of chilli as the intercrop on the girth of rubber

Crop	Age of rubber trees (months)
	30	33	36
Girth (cm) with chilli as intercrop	15.7	19.6	22.3
Girth (cm) without intercrop	14.1	15.5	18.1

Optimization of rubber based farming systems

It is essential that rubber smallholders in Indonesia have a minimum income of US$1500/year/family or Rp4,000, 000/year/family to achieve a normal standard of living³. This can be achieved by developing the optimum farm models. These activities depends on the availability and optimum utilization of resources such as commodities, land, capital and labour.

The constraints and potentials for commodities and other resources for the development of farming systems in South Sumatra include:

1. Rubber is used as the main crop for farming systems activity due to its adaptability to grow in red-yellow podzolic type of soil and this crop can guarantee the farmers livelihood in the long term⁶. One of recommended clone for the South Sumatra region is PR 261 which has an average production of about 1311kg drc/ha/year.

2. Sufficient food crops are needed to support the farmer's family. This need can be satisfied by practising the food crops cropping pattern (corn + upland rice - soybean - cowpea).

3. Livestock should be included in order to have a continuous income before tapping and reduce the dependence on rubber after tapping. The raising of draught animals such as cattle will give additional income to the farmer and can also be used as a labour substitute whenever labour is in short supply. Depending on the availability of forage in the rubber smallholder area, the maximum number is less than 12 head/farmer.

4. The total land available for each farmer in South Sumatra is about 3.0ha.

5. The capital available is less than Rp4,000,000/year (US$1500/year).

6. The family labour available is less than 630 MD/year (MD = man days).

The optimum farm models, using linear programming analysis, could be built from the potential resources within the general constraints of farming systems in South Sumatra. The optimum rubber based farming system can be achieved by planting 1.4ha of rubber (PR 261), 0.5ha of food crops and 3.0 head of cattle and needs 630 man days/year. It generated an income of Rp4,751,291/year (Table 9).

Table 9 Result of optimisation of rubber based farming systems

Items	Optimum model
Revenue	Rp7,907,672
Land needed	2.13ha
Rubber area	1.4ha
Food crops	0.5ha
Number of cattle	3 head
Labour needed	630 MD
Capital	Rp3,156,381
Income	Rp4,751,291
(>US$1500)

Conclusions

Smallholder rubber condition in Indonesia could be improved by developing rubber based farming systems. There were three steps for developing rubber based farming systems:

1 . Providing recommended planting materials through farmer groups;

2. Developing a technological intercropping package for use during the immature rubber period;

3. Investigating the optimum scale of rubber based farming systems.

Farmer groups in South Sumatra and Jambi Province could provide the recommended rubber planting material (PR 261 and BPM 24). The direct benefit of these programmes are:

1. To stimulate farmers to plant clonal planting material;

2. To reduce the cost of planting material and to make it available at the village level;

3. To give knowledge to the farmers of appropriate practises.

Both food and horticulture crops were able to be intercropped during immature rubber period and had no negative effect on rubber growth.

The optimum rubber based farming systems can be achieved by planting 1.4ha of rubber (PR 261), 0.5ha of food crops and 3.0 head of cattle. This farming systems needed 630 man days/year and generated an income of Rp4,751,291/year.

References

1. Directorate of General Estate (DGE)., Statistical Estate Crops of Indonesia., Rubber,1995.

2. Nancy, C., C. Anwar and A. Tjasadihardja., Smallholder rubber replanting by self-assistance through the establishment of budwood garden and nursery at farmer's level., National Rubber Conference, Indonesian Rubber Research institute, 1994.

3. Arifin, S., M.J. Rosyid, G. Wibawa, A.D. Gozali and M. Delabare., Land management towards improvement of rubber samllholders in Indonesia., Proc. ANRPC 6th Seminar on Progress and Development of Rubber Smallholder, Indonesia., Association of Natural Rubber Producing Countries, Kuala Lumpur, 1986.

4. Chandresekera, L.B., Intercropping of rubber replanting in the immature stages., Proc. ANRPC 4th Seminar on Progress and Development of Rubber Smallholder, Sri Lanka., Association of Natural Rubber Producing Countries, Kuala Lumpur, 1980.

5. Kaewbamroong, M., Pineapple (Nanas) as an intercrop between rubber rows at Phuket., Proc. ANRPC 2nd Seminar on Progress and Development of Rubber Smallholder, Thailand., Association of Natural Rubber Producing Countries, Kuala Lumpur, 1976.

6. Effendi, S., Improvement of smallholder rubber farming productivity in Indonesia., Proc. Rubber Industry Workshop, ACIAR, Australia, 1985.