Performance of an improved fallow system in the Peruvian Amazon—modelling approach

As traditional slash-and-burn systems with prolonged fallow periods are no longer feasible in most parts of the tropics, improved agroforestry systems have high potential to increase the productivity of farming systems and sustain continuous crop production. Our objective was to assess biophysical and economic performance of planted leguminous tree fallow (using Inga edulis) compared to the traditional slash-and-burn farming system, practiced by farmers on fields infested with noxious weedy grass Imperata brasiliensis around the city of Pucallpa, Peru. An existing agroforestry model SCUAF was used to predict biophysical factors, such as changes in soil characteristics and farm outputs (crop and tree yield). While a cost–benefit analysis spreadsheet, which uses the output from SCUAF and economic data on input/output levels and prices, calculates economic performance of the systems. The Inga fallow system can provide improvements to a range of soil biophysical measures (C, N, P content). This enables higher levels of farm outputs to be achieved (higher cassava yields). However, for smallholders the improved system must be more economically profitable than the existing one. At prices currently encountered, the Inga fallow system is more profitable than the Imperata fallow system only in the long-term. In adopting the Inga fallow system, smallholders will incur lower profits in the first years, and it will take approximately 10 years for smallholders to begin making a profit above that achievable with the Imperata fallow system. Unless smallholders are capable of accepting the lower profitability in first years, they are less likely to adopt the new system.     

The Imperata grasslands of tropical Asia: area, distribution, and typology

The rehabilitation or intensified use of Imperata grasslands will require a much better understanding of their area, distribution, and characteristics. We generated estimates of the area of Imperata grasslands in tropical Asia, and suggested a typology of Imperata grasslands that may be useful to define the pathways toward appropriate land use intensification. We conclude that the area of Imperata grasslands in Asia is about 35 million ha. This about 4% of the total land area. The countries with the largest area of Imperata grasslands are Indonesia (8.5 million ha) and India (8.0 million ha). Those with the largest proportion of their surface area covered with Imperata are Sri Lanka (23%), the Philippines (17%), and Vietnam (9%). Laos, Thailand, Myanmar, and Bangladesh evidently all have similar proportions of their land area infested with Imperata (about 3 to 4%). Malaysia (< 1%), Cambodia (1%), and the southern part of China (2%) have but a minor proportion of their total land area in Imperata. The species was found widely distributed on the full range of soil orders. It occupied both fertile (e.g. some of the Inceptisols and Andisols) and infertile soils (Ultisols and Oxisols) across a wide range of climates and elevations. Imperata lands fall into four mapping scale-related categories: Mega-grasslands, itmacro-grasslands, meso-grasslands, and micro-grasslands. The mega-grasslands are often referred to as sheet Imperata. They are the large contiguous areas of Imperata that would appear on small-scale maps of say 1:1,000,000. We propose that this basic typology be supplemented with a number of additional components that have a key influence on intensification pathways: land quality, market access, and the source of power for tillage. The typology was applied in a case study of Indonesian villages in the vicinity of Imperata grasslands. We propose an international initiative to map and derive a more complete and uniform picture of the area of the Imperata grasslands. This should include selected studies to understand conditions at the local level. These are critical to build the appreciation of change agents for the indigenous systems of resource exploitation, and how they relate to local needs, values and constraints.     

The agroforest alternative to Imperata grasslands: when smallholder agriculture and forestry reach sustainability

Basic prerequisites for sustainable reforestation of Imperata grasslands in Southeast Asia are presented. A theoretical forest is designed according to these prerequisites. Composed of basic units managed by local smallholders, the forest is composed of two sets of commercial tree species suited to local conditions, one set providing regular cash income and the other providing seasonal or irregular cash income. Such composition ensures economic and ecological viability of the forest in the long run, provided that clear tenurial right on the basic units are recognized. Guidelines for a transition from Imperata grasslands to forest are presented, underlining the importance of relying on natural succession processes. The theoretical forest is identified as an agroforest, a diverse forest rebuilt and managed by farmers, providing forest and agricultural products for both cash income and household consumption. Agroforests have been developed for decades by indigenous farmers in some regions of Southeast Asia. Examples from Indonesia are presented to support the theoretical analysis. They show that the agroforest alternative is a valuable unifying concept for reforestation of Imperata grasslands, for a sustainable upland agriculture, and more generally for an equitable environmentally and economically sound development of rural areas in the humid tropics. sound development of rural areas in the humid tropics.     

Increasing rubber planting density to shade Imperata: a bioeconomic modelling approach

The profitability to smallholders of rubber production in Imperata infested areas of Indonesia was assessed using an existing bioeconomic model. An Imperata groundcover component was incorporated within the model as follows: tree girth = f(Imperata groundcover) = f(relative shading) = f(crown height, canopy width, tree spacing) = f(tree girth). The first two relationships represent extensions to the original model.Cumulative tree girth was predicted for rubber planting densities from 400 to 1000 stems/ha. At low tree planting rates, competition from Imperata restricts tree growth. At high tree planting rates, Imperata is controlled, but there are negative consequences from inter-tree competition. These two effects of higher planting rates counterbalanced, such that tree girth was approximately constant across the range of tree densities.Tree girth is a driving force in determining latex yield. Latex yield was translated into present value net economic returns within the model, by reference to prices and costs associated with rubber production in South Sumatra, Indonesia in 1995. Economic returns from planting 400 to 1000 trees/ha were calculated. Rubber growing by smallholders on Imperata infested land, was found to be profitable. Maximum profitability was obtained at 600 trees/ha. However, the sensitivity of net economic returns, with respect to tree density, was not great. This was due to the counterbalancing effects of changes in tree density.     

Food-crop-based production systems as sustainable alternatives for Imperata grasslands?

Purely annual crop-based production systems have limited scope to be sustainable under upland conditions prone to infestation by Imperata cylindrica if animal or mechanical tillage is not available. Farmers who must rely on manual cultivation of grassland soils can achieve some success in suppressing Imperata for a number of years using intensive relay and intercropping systems that maintain a dense soil cover throughout the year, especially where leguminous cover crops are included in the crop cycle. However, labour investment increases and returns to labour tend to decrease in successive years as weed pressure intensifies and soil quality declines.Continuous crop production has been sustained in many Imperata-infested areas where farmers have access to animal or tractor draft power. Imperata control is not a major problem in such situations. Draft power drastically reduces the labour requirements in weed control. Sustained crop production is then dependent more solely upon soil fertility management. Mixed farming systems that include cattle may also benefit from manure application to the cropped area, and the use of non-cropped fallow areas for grazing. In extensive systems where Imperata infestation is tolerated, cassava or sugarcane are often the crops with the longest period of viable production as the land degrades.On sloping Imperata lands, conservation farming practices are necessary to sustain annual cropping. Pruned tree hedgerows have often been recommended for these situations. On soils that are not strongly acidic they may consistently improve yields. But labour is the scarcest resource on small farms and tree-pruning is usually too labour-intensive to be practical. Buffer strip systems that provide excellent soil conservation but minimize labour have proven much more popular with farmers. Prominent among these are natural vegetative strips, or strips of introduced fodder grasses.The value of Imperata to restore soil fertility is low, particularly compared with woody secondary growth or Compositae species such as Chromolaena odorata or Tithonia diversifolia. Therefore, fallow-rotation systems where farmers can intervene to shift the fallow vegetation toward such naturally-occurring species, or can manage introduced cover crop species such as Mucuna utilis cv. cochinchinensis, enable substantial gains in yields and sustainability. Tree fallows are used successfully to achieve sustained cropping by some upland communities. A variation of this is rotational hedgerow intercropping, where a period of cropping is followed by one or more years of tree growth to generate nutrient-rich biomass, rehabilitate the soil, and suppress Imperata. These options, which suit farmers in quite resource-poor situations, should receive more attention.     

The dynamics of Imperata: historical overview and current farmer perspectives, with special reference to South Kalimantan, Indonesia

The paper reviews modern attitudes to and uses of imperata grasslands in parts of Southeast Asia, including government and NGO efforts at reforestation. It is argued that the perspective of small farmers has usually been inadequately considered in planning the rehabilitation of Imperata. A historical overview of the impact of changes in land use, population, vegetation dynamics and human adaptation on the creation, disappearance or persistence of Imperata provides a context for the present concerns and emphasizes the wide variability of the situation at the local level. Nine questions are proposed as needing consideration whenever changes are planned to a grassland-based system. They cover three main areas: 1) the origins, past and present uses of the grasslands (including the present land tenure position and variations in uses by ethnic group, socio-economic status and gender); 2) perceptions by farmers of the opportunities and constraints provided by local micro-environments, particularly vegetation types; 3) farmer suggestions for ways of improving their economic status and the potential benefits of agroforestry innovations. These questions are applied to one case study area, the Riam Kiwa valley of South Kalimantan, Indonesia.     

Soil fertility management for reclamation of Imperata grasslands by smallholder agroforestry

Imperata cylindrica grasslands are widely believed to indicate poor soil fertility. Soil fertility improvement may have to be an important component of a reclamation strategy. Data for Sumatra, Indonesia indicate, however, that Imperata occurs on a broad range of soil types and is not confined to the poorest soils. A direct role of Imperata in soil degradation cannot be ascertained. In many instances, however, Imperata soils are low in available P and effective N supply. The use of rock phosphate in combination with erosion control (fertility traps) and legume cover crops can be effective in restoring soil fertility. Case studies for a number of sites in Sumatra have confirmed the practical possibility of reclaiming grasslands for food and tree crops.     

Imperata economics and policy

Should policymakers — or anyone else — care about millions of ha of Imperata grasslands? The answer depends on the balance between costs of conversion to other uses and the net benefits produced in economic growth, poverty alleviation, and protection of the environment. The first section on Imperata economics sets up the analytical framework to address this question and draws on the wider development economics literature to consider whether growth and poverty alleviation are conflicting or complementary objectives. Although evidence is limited, it suggests smallholder-based agroforestry could provide the same economic growth with greater poverty alleviation than large-scale forestry estates. There is, however, no substitute for project appraisal for specific settings. The second section on Imperata policy reviews whether policy distortions and market failures provide a sufficient rationale for direct policy intervention to promote tree planting on Imperata grasslands. Estimates of imputed values of carbon sequestration to alleviate global warming are presented for Acacia mangium and rubber agroforestry. The conclusion summarizes the policy research agenda and examines the desirability and feasibility of policy intervention to promote carbon sequestration through Imperata grassland conversion to tree-based systems.     

Tree-crop interactions in hedgerow intercropping with different tree species and tea in Sri Lanka: 2. Soil and plant nutrients

The main aim of this study is to review the environmental and socioeconomic sustainability of the gum arabic farming system in central Sudan. A further aim is to analyse some of the main factors influencing production in recent decades in order to understand the future trade potential and consequently the smallholder livelihood. The study shows that end-user imports of gum arabic have increased during recent decades. Gum arabic is mainly for uses such as soft drinks, confectionary, and pharmaceuticals. However, even with this increased demand the production in Sudan, the main country of production, is declining. The producers, mainly smallholders, suffer from fluctuating prices. If the gum arabic farming system should be able to provide the environmental benefits of improved soil fertility and the socioeconomic benefits of risk spreading and dry season income opportunities, the prices paid to smallholders must be stabilized at a fair level, otherwise a shift to other crops or practices might take place.     

Agricultural diversification among smallholder rattan cultivators in Central Kalimantan,Indonesia

Many developing countries are trying to promote agricultural diversification among smallholders because they feel that smallholders are too dependent upon a narrow range of crops. Fieldwork among smallholder rattan cultivators in Southern Borneo, Indonesia, suggests that smallholders do maintain a poorly diversified portfolio of agricultural activities. Farmers rely heavily upon rattan because of its superior profitability. A number of economic and agronimic constraints however prevent farmers from diversifying out of rattan into other crops.     

Soil properties of Imperata grasslands and prospects for tree-based farming systems in Northeast Luzon, The Philippines

Ambiguity in the potential of soils under Imperata cylindrica grass contributes to the slow pace of grassland development in Northeast Luzon. The aim of this study is to investigate the soil properties of Imperata grassland and the prospects for tree-based farming systems in northeastern Luzon. Soils are developed over Miocene-Pliocene sedimentary rock and Plio-Pleistocene volcanic and fluvial deposits. There is a clear distinction between relatively well-developed fertile soils (Cambisols, Luvisols) along hill slopes, clayey soils in lowlands (Vertisols) and inferior leached soils (Planosols) restricted to palaeo terraces and elevated surfaces. Low soil organic matter content is a regional constraint to grassland development. Other constraints mainly occur on a local level and are associated with soil physical, rather than soil chemical, properties such as low infiltration, surface crusting, gully formation, limited soil depth, and stony surfaces. It is argued that variable soil conditions and topography are inadequately considered in regional attempts to develop and rehabilitate grasslands. Fertile, low-angle foot slopes are most suitable to permanent cultivation with crop rotation and husbandry practices such as mulching of crop residues, efficient use of animal manure and inclusion of nitrogen-fixing plants. Enrichment of natural forest patches is proposed, together with mixed tree plantations on rocky and steep terrain, field boundaries and stream banks in cultivated areas. Less fertile palaeo terraces, watersheds and upper slopes are most suitable to silvipastoral systems.This revised version was published online in November 2005 with corrections to the Cover Date.     

Fire management on Imperata grasslands as part of agroforestry development in Indonesia

Fire is an important factor in the Imperata grassland ecosystem. It prevents or slows down the natural succession to shrubs and/or secondary forest vegetation and is a major threat to (agro)forestry options for Imperata grassland rehabilitation. Forest fires can also be a primary cause of the extension of Imperata grasslands. In this review an attempt is made to integrate biophysical and socioeconomic aspects of the causation of fires in a conceptual model. Fire effects on vegetation are examined. The management options at the level of a farmer, a village community and a national government are analyzed.     

Gmelina arborea– a viable species for smallholder tree farming in Indonesia?

Across Indonesia there are millions of hectares of degraded land in need of rehabilitation. There is interest at both the government and farmer level of converting some of these lands to more productive use, including growing trees. Smallholders often practice tree farming to generate income and traditionally cultivate a wide range of tree species in mixed agroforestry systems. Grown to satisfy both household needs and market demand, smallholder-produced timber might play a potentially important role in local markets. Tectona grandis, Swietenia macrophylla, and Paraserianthes falcataria are common smallholder timber species. Gmelina arborea (gmelina) is easy to cultivate and grow at the smallholder level. It has been widely grown in plantations in South and Southeast Asia, including Indonesia. However, gmelina is not yet a priority species with Indonesian smallholder farmers. Experience indicates that marketable small-diameter gmelina timbers can be produced in 7–10 years and that price compares well with that of Paraserianthes, the most widely grown short-rotation smallholder timber species in Indonesia. Most gmelina seed originates in Central Java, from where large quantities of seed are shipped annually to other parts of Indonesia. This seed is of uncertain quality, as seed sources are unidentified and seed collection guidelines are not used. It is recommended to establish smallholder plantations with seed of known quality. Gmelina holds promise as one component for a multi-species smallholder tree farming systems to produce short-rotation timbers for household use and local markets. Palabras clave: Agroforestales, Ensayos agrícolas, Producción de madera por pequeños propietarios, Rehabilitación de tierras, Selección de especies Resumen. A través de Indonesia, hay millones de hectáreas de terrenos degradados los cuales necesitan ser rehabilitados. Existe interés tanto al nivel gubernamental como al nivel de los agricultores, en convertir algunos de estos terrenos en sitios productivos, incluyendo la producción de árboles. Con frecuencia, para generar ingresos, los pequeños propietarios plantan árboles para cosecha y tradicionalmente cultivan un amplio rango de especies de árboles, en una variedad de sistemas agro-forestales. La madera de los pequeños propietarios, producida para satisfacer tanto las necesidades hogareñas como las demandas del mercado, puede jugar un papel potencialmente importante en los mercados locales. La Tectona grandis, la Swietenia macrophylla, y el Paraserianthes falcataria son especies comúnmente producidas por los agricultores. La Gmelina arborea (gmelina) es una especie de fácil cultivo y crecimiento al nivel de los pequeños propietarios, y se ha venido produciendo ampliamente en el sur, y el suroriente de Asia, incluyendo Indonesia. Sin embargo, la gmelina no es aún una especie de prioridad para los pequeños agricultores de Indonesia. La experiencia indica, que la madera de gmelina de pequeño diámetro puede salir al mercado en un período de 7–10 años y que el precio de esta madera es comparable con la madera del Paraserianthes, la cual es la especie de corta rotación más ampliamente utilizada por los pequeños propietarios en Indonesia. La mayoría de la semilla de la gmelina proviene de Java Central, de donde se envían anualmente grandes cantidades de semilla a otras partes de Indonesia. Esta semilla es de calidad incierta, ya que las fuentes de semilla no están identificadas y no se utilizan normas de colección de semillas. Se recomienda que las plantaciones de los pequeños propietarios sean establecidas con semilla de calidad conocida. La gmelina es prometedora como parte del sistema de cultivo de árboles de especies múltiples de los pequeños propietarios, para producir madera de corta rotación para ser utilizada localmente y enviada a mercados locales.     

Livestock production systems for Imperata grasslands

With or without human intervention, animals are important components of grassland and forest ecosystems. When settlers occupy and cultivate land, they invariably bring animals with them. Livestock integrated in the production system convert crop residues and weeds into valuable products while most plant nutrients are retained. As animal feed, Imperata has low nutritional value, especially with advancing maturity. Supplemental feeding of ruminants with urea-molasses-mineral blocks or introduction of fodder species, especially legumes, have significantly improved production under smallholder farm systems. Fodder species for fallow improvement, modified alley cropping or hedgerow systems, and plantations integrating livestock production, all hold promise for future use of Imperata grasslands. Diversified systems may help settlers reach self-sufficiency while increasing the sustainability of the system. Research and development interventions towards improved livestock productivity in smallholder farms may have low economic but high social benefit. These benefits are especially attainable if the farm families participate in the design and implementation of innovations. Security of land tenure, provision of credit, and mechanisms marketing of produce are issues that need to be addressed in more innovative ways.     

Early effects of four fast-growing tree species and their planting density on ground vegetation in Imperata grasslands

Ground vegetation development was studied under young plantations of Acacia mangium, A. crassicarpa, Gmelina arborea and Paraserianthes falcataria on an Imperata grassland site in South Kalimantan, Indonesia. The study was based on two separate trials: 1) a species trial with a spacing of 3×3 m, and 2) a spacing trial with progressively decreasing planting density. Both trials were established by use of intensive site preparation, NPK-fertilization, and weeding during the first year. Two years after planting and one year after the last weeding, ground vegetation in the first trial was dominated by Imperata cylindrica grass and shrubs Chromolaena odorata and Clibadium surinamense. In the open area (control) only Imperata grass appeared. Significant differences in total ground vegetation biomass (t ha^–1) between the tree species were as follows: G. arborea (0.2) A. mangium (1.4) A. crassicarpa (4.2) < P. falcataria(9.6) open area (11.4). The early results from the spacing trial showed similar trends in the hardwood species' abilities in Imperata suppression. Highly significant linear relationships existed in regression analysis between the distance between planted trees and the ground vegetation biomass as follows: G. arborea (r²=0.75), A. mangium (r²=0.95), A. crassicarpa (r²=0.97), P. falcataria (r²=0.96). Tree species and their planting density should thus be critically considered in forest plantation establishment on Imperata grasslands, since ground vegetation development plays a decisive role in fire susceptibility, maintenance requirements and the promotion of native species in plantations.     

Drivers of adoption of eucalypt tree farming by smallholders in Thailand

Eucalypt (Eucalyptus spp.) tree farming is a source of income for many smallholders in developing and emerging countries and critical to the resource supply of many pulp and paper companies. These companies rely on smallholders adopting tree farming, sometimes by offering a contract. This paper reports a study from four regions of Thailand, where smallholder eucalypt tree farming is important, which investigated what characteristics of smallholders were associated with greater adoption of tree farming. A total of 461 eucalypt tree farmers and 171 non-tree farmers were randomly selected and surveyed in these regions, using a door-to-door household survey. A logit analysis corroborated hypotheses about the drivers of adoption. Qualitative analyses were used to inform interpretation of the quantitative results and shed light on the role of eucalypt tree farming in smallholders’ livelihood. Results demonstrate that those with suitable land available are more likely to adopt eucalypt tree farming than others. In addition, perception of land tenure security matters in the adoption of tree growing, but holding a formal land tenure document does not. Adoption of eucalypt tree farming in Thailand is not part of a land use intensification strategy. Instead, eucalypts are used as an alternative crop for low productivity land, on which eucalypts are the most profitable crop. Eucalypt tree farming also gives smallholders an opportunity to diversify their income. In addition, this alternative land use has the advantage of requiring low labour inputs between planting and harvest. This is particularly advantageous for many tree growers who have off-farm income or rely on hired labour for farming their land.     

Trade-offs between rubber production and maintenance of diversity: the structure of rubber gardens in West Kalimantan, Indonesia

The goal of this study was to assess the potential of small-holder rubber cultivation in agroforestry gardens to fulfill simultaneously the goals of conservation and sustainable rural development. I examined the structure and species composition of trees in 11 rubber gardens in West Kalimantan, Indonesia, using a single 0.10 ha plot per garden. Although 41 distinct morphotypes were encountered, rubber (Hevea brasiliensis) dominated the sample of 370 trees. Richness within plots varied (3–15 morphotypes), as did the predominance of rubber (24–97% of all basal area, 24–91% of all individuals). The importance of rubber within a garden was significantly negatively correlated with the number of morphotypes present. This result suggests that tree diversity may limit potential productivity of rubber gardens. Thus, small-holders may not be willing to maintain diversity at the scale of a single garden. Although species-accumulation curves indicate that substantial tree diversity may exist across all rubber holdings, diversity is likely to be lost from the system if individual owners reduce species richness in their gardens. Rubber agroforestry as currently practiced in West Kalimantan is not an ideal model for matching rural development needs with the achievement of conservation goals. Other models, such as tengkawang- and durian-based fruit gardens, do exist in Kalimantan and elsewhere, and should be evaluated for incorporation into policy and development strategies.     

Economic opportunities for smallholders to combine pulpwood trees and food crops

Input/output data from tree growing experiments in Southeast Asia were analysed within the framework of a model of a smallholder farm. Data on cropping were obtained from surveys of farmers. Prior to formulating a whole farm model, this input/output data were modified in two ways: (a) a yield penalty was imposed upon a continuous cropping regime to reflect the impact of land degradation; (b) an agroforestry (intercropping) activity was synthesised by reference to an existing agroforestry bioeconomic model. The modelling framework was conventional linear programming. The interplay of land area availability, land and labour productivity, and interest rates lead to a relatively complex picture, even for the simplified farming systems that were examined. Model results showed a clear indication of the potential role of trees, but this potential role decreased with increasing interest rates. The analysis suggested that smaller farms will be less inclined towards tree growing. A mixture of trees and crops appears attractive, on purely economic grounds, over a wide range of interest rates and land areas. Consideration of factors outside the model, such as risk aversion objectives of smallholders, and their limited opportunities to borrow for investments in tree planting, reinforce the tendency to combine trees and crops.     

Prioritizing Underutilized Tree Species for Domestication in Smallholder Systems of West Java

This paper provides an overview of a tree species prioritization study of underutilized tree species in a participatory tree domestication program for smallholders in Indonesia. The study was conducted in three villages of Nanggung sub-district, Bogor district via farmer surveys, focus group discussion, SWOT analysis and evaluation of markets and germplasm sources. Five priority species were identified: Manglietia glauca, Parkia speciosa, Durio zibethinus, Gmelina arborea and Sandoricum koetjape. These species are promising components of agroforestry systems to enhance smallholder livelihoods and can grow under the low management conditions common in smallholder systems. They represent indigenous and exotic tree types that produce timber, fruit or spices within the domestication continuum. Furthering the domestication and utilization of these species requires the identification and dissemination of available germplasm sources, the dissemination of high-quality germplasm and the development of farmer-friendly propagation and tree management practices. Also, as with most smallholder systems, the marketing practices for the products of these five species require improvement, starting with the production of reliable quantities of high quality tree products.     

Why do Farmers Prefer Oil Palm? Lessons Learnt from Bungo District,Indonesia

Indonesia has been the world’s largest producer and exporter of palm oil since 2008. This paper discussed the livelihood impacts of oil palm development in Indonesia, based on lessons learnt from Bungo district, in the province of Jambi. The various community-company partnerships that structure the sector are reviewed and the difficulties raised by the joint ventures schemes are discussed. The merits and drawbacks of oil palm as a smallholder crop are then analysed, based on household socio-economic surveys conducted in 2007–2010. The main causes of conflicts between oil palm companies and communities are unclear land tenure, and a recurrent lack of leadership in smallholders’ cooperatives. Under fair partnerships between smallholders and companies, oil palm could become a smallholder friendly crop. The land-use profitability analysis demonstrates the high returns that can be generated by oil palm independent smallholdings, making it highly competitive with rubber, and much more profitable than rice production.