Cost-benefit analysis of alternative forms of hedgerow intercropping in the Philippine uplands

Considerable resources have been expended promoting hedgerow intercropping with shrub legumes to farmers in the Philippine uplands. Despite the resources committed to research and extension, persistent adoption by farmers has been limited to low cost versions of the technology including natural vegetation and grass strips. In this paper, cost-benefit analysis is used to compare the economic returns from traditional open-field maize farming with returns from intercropping maize between leguminous shrub hedgerows, natural vegetation strips and grass strips. An erosion/productivity model, Soil Changes Under Agroforestry, was used to predict the effect of erosion on maize yields. Key informant surveys with experienced maize farmers were used to derive production budgets for the alternative farming methods. The economic incentives revealed by the cost-benefit analysis help to explain the adoption of maize farming methods in the Philippine uplands. Open-field farming without hedgerows has been by far the most popular method of maize production, often with two or more fields cropped in rotation. There is little persistent adoption of hedgerow intercropping with shrub legumes because sustained maize yields are not realised rapidly enough to compensate farmers for establishment and maintenance costs. Natural vegetation and grass strips are more attractive to farmers because of lower establishment costs, and provide intermediate steps to adoption. Rural finance, commodity pricing and agrarian reform policies influence the incentives for maize farmers in the Philippine uplands to adopt and maintain hedgerow intercropping. This revised version was published online in August 2006 with corrections to the Cover Date.     

Enhancing the food security of upland farming households through agroforestry in Claveria,Misamis Oriental,Philippines

The impact of agroforestry on food security of upland farmers is least recognized and appreciated given that the linkage between them is quite complex and not well understood. The crucial role of agroforestry in enhancing food supply and augmenting family income is commonly ignored. This study aimed to get a deeper understanding of the role of agroforestry in ensuring food security of farming households in the Philippine uplands. A combination of participatory approaches including participatory rural appraisal, household survey, focused group discussions, field experiments and simulation modeling were used for the study conducted in Claveria, Northern Mindanao, Philippines. The first major finding was that the prime responsibility for ensuring adequacy of food production and supply for the farming households rested on the husband and wife. The second major finding based on the simulation results was that agroforestry increased and stabilized corn yields under hedgerow system. Moreover, fruits from perennial crops and trees served as secondary food crops especially during lean months of food supply. The last major finding was that the adoption of agroforestry significantly increased the level of benefits by around 42–137%, compared with the low income from continuous annual monocropping. The key to making upland farm households food secure is to increase the productivity of their farms and home gardens. A good start is to promote the agroforestry system in upland areas, and it is thereby recommended that both national and local government units mainstream their policies and efforts toward promotion of agroforestry adoption in the Philippine uplands.     

Conservation farming practices for small reservoir watersheds: a case study from Sri Lanka

Traditional agricultural villages in the dry zone of Sri Lanka are minor watersheds where small earth bank reservoirs provide water for irrigation and domestic purposes. The farmers practise rainfed farming on a shifting basis called chena in the reservoir catchments, which are being degraded due to soil erosion. The consequent sedimentation in reservoirs has reduced the extent of irrigation, and the total farming system has lost its ecological balance and economic sustenance. The present study aimed at identifying suitable farming methods for reservoir catchments in order to prevent further deterioration.The investigation was carried out on plot basis to assess soil loss and runoff from forest, scrub and cultivated lands as well as from four other types of farming lands namely plough-farming, bund-farming and two conservation farming practices: strip mulch and graded hedgerow farming. In graded hedgerow farming hedgerow trees are planted across the slope with a mild gradient of 0.4–0.5%. The study was carried out in a reservoir watershed at Maha Illuppallama, Sri Lanka during 1989/90 major rainy season.Results indicated that the two conservation farming practices generate 33–34% annual runoff while replenishing soil moisture of the watershed. Soil loss data showed that the conservation farming practices provide more than 80% protection against soil erosion while bunding can provide only 40% protection compared to existing shifting cultivation practices.     

Agroforestry in the management of sloping lands in Asia and the Pacific

Steeply sloping lands are widespread in the tropics. An estimated 500 million people practice subsistence agriculture in these marginal areas. Continued population growth has led to the intensified cultivation of large areas of the sloping lands, exacerbating the problem of soil erosion. Although research shows that alley cropping and other contour agroforestry systems can stabilize the sloping lands, these systems have not been widely adopted by farmers. The Framework for Evaluating Sustainable Land Management (FESLM) has been tested in sloping land areas in the Philippines. Sustainable land management must be productive, stable, viable, and acceptable to farmers, while protecting soil and water resources. Farms on which contour hedgerow intercropping has been adopted meet the multifaceted requirements of FESLM, whereas the farmers' current practice does not. Appropriate land management measures for particular locations depend on a complex suite of social, economic, and biophysical factors, and need to be developed in participation with farmers. The role of agroforestry in sustainable management of sloping lands is the subject of networks coordinated by the International Board for Soil Research and Management (IBSRAM) in seven countries in Asia (ASIALAND) and four countries in the Pacific (PACIFICLAND). We review selected outcomes from a wealth of network data. From these results the following conclusions about the sustainability of various agroforestry systems for sloping lands can be drawn: • In the Pacific, soil loss from sloping lands due to water erosion under farmers' current practices is episodic, unpredictable, and possibly not severe; • Agroforestry systems that utilize legume shrubs, fruit trees, coffee (Coffea spp.) or rubber (Hevea brasiliensis) provide useful economic returns, but are not an essential component in terms of soil protection because grass or pineapple (Ananas comosus) planted on the contour are equally effective in reducing erosion; • Agricultural intensification will lead to nutrient mining, reduction of aboveground biomass, declining yields, and less soil protection unless external sources of nutrients are used; • nitrogen can be effectively supplied using legumes; • Cash derived from hedgerow trees and/or shrubs may providean incentive for their adoption by farmers, as well as funds to purchase external inputs such as fertilizers; • Labor may be a major constraint to the adoption of complex agroforestry systems. We also discuss the information management systems required to effectively manage and utilize the extensive sets of experimental and indigenous data being accumulated. We believe such information systems can facilitate technology transfer across and between regions, and improve the efficiency of research into agroforestry and other land-management approaches. This revised version was published online in June 2006 with corrections to the Cover Date.     

Upland agriculture,the land frontier and forest decline in the Philippines

Population pressure, expansion of small-scale agriculture and shifting cultivation are commonly cited as the causes of tropical deforestation. A close examination of deforestation and agriculture in the Philippine uplands reveals, however, that the vast majority of agriculturists must be sedentary farmers. In addition, the importance of population pressure as a cause of deforestation in the Philippines cannot be supported by the available evidence. Lastly, the concept of arable land is shown to be of limited value in discussing upland agriculture in the Philippines.     

Financial evaluation of smallholder timber-based agroforestry systems in Claveria, Northern Mindanao, the Philippines

In the Philippines, timber production on small farms has become profitable as a result of reduced supplies due to extensive deforestation and increasing demand. In the early 1990s, when the price of timber was high, farmers were promised huge returns from tree farming. However, widespread planting of few species has led to oversupply and a sharp decline in the price of farm-grown timber. Moreover, low intercrop yields as a result of competition from fast-growing trees and low timber yields due to poor tree management, further reduce net economic returns. In spite of this, interest in tree farming remains high. This paper examines the private profitability of two tree-maize systems, namely trees in blocks and trees in hedgerows, compared with the alternative of maize monocropping. The analysis reveals that maize monocropping provides higher returns to land at the current timber price, but considerably lower returns to labour, than the maize-tree systems tested. This suggests that tree farming is a more attractive option for labour and capital-constrained households or those with off-farm opportunities that compete for their labour. These farmers may raise productivity and income by planting trees on the excess land that cannot be devoted to annual crops. The analysis also indicates that wide-spaced tree hedgerows are superior to tree blocks, due to lower establishment and management costs, longer periods of viable intercropping and more rapid tree growth.     

Farmer adoption of contour hedgerow intercropping,a case study from east Indonesia

The results of a study to assess the initial impact of the introduction of contour hedgerow intercropping on the Indonesian islands of Lombok and Sumbawa are described. The study focused on the reasons for adopting this technique and its initial effect. The results of detailed case studies in four villages indicated that the process of adoption is heterogeneous. Land-use conditions in the four villages were much more diverse and dynamic than the project anticipated. Rather than being an off the shelf technique as assumed by the project, hedgerow cropping proved to be a prototype technique; the farmers' ability to adapt the practice to their specific farming conditions such as subsistence food production or cash crop cultivation was an important motive for its adoption. In some cases the introduction competed with the extension of other promising land-use practices. Several farmers adopted the technique not because of its productive benefits, but as a means to gain access to land or credit, or to demonstrate their allegiance to social networks. The results indicate that there were significant discontinuities between what the project intended to achieve by introducing the technique and the farmers' motives for adopting it.     

Contour hedgerow intercropping in the mountains of China: a review

Hedgerow intercropping systems were introduced in China in early 1990s. Achievements in research and extension of contour hedgerow intercropping in China during the past 15 years are reviewed here. Results reported in over 70 published papers have shown that hedgerow intercropping contributes to soil and water conservation, soil fertility amelioration, land productivity improvement, bio-terrace formation, and gives more options for income generation based on local resources in mountain areas. Research and demonstration works on contour hedgerow systems have achieved success by integrating local resources and needs into the system, especially in the dry valleys of the upper reaches of the Yangtze River, and the Three Gorges region. Contour hedgerow intercropping has attracted the attention of researchers, policy-makers, and farmers, and has been taken as an alternative to implementation of the Grain for Green policy, and ecological reconstruction and restoration today. To date, hedgerow intercropping has been demonstrated and applied practically on sloping land in more than six provinces of China, particularly Sichuan, Guizhou, Shanxi, Shaanxi, as well as in the Three Gorges region of Chongqing and Hubei Province. The intercropping system has also been practiced as an optimized technology for conserving farming on sloping lands, improving cash income, and reducing agricultural risks in depressed mountainous regions in southwest and northern China over recent years. Some misunderstandings and problems in studies and extension of the system in China are summarized and clarified, and some recommendations for further research and expansion of the system are also presented in this paper.     

Indexing Soil Conservation

Abstract

Soil erosion poses economic and environmental concerns in many tropical uplands. Agroforestry has been proposed as a sustainable land use that can mitigate soil erosion and promote the economic welfare of small farmers. To evaluate such claims, we must (a) develop a composite measure of effectiveness, such as a soil conservation index, and (b) define it in terms understood by the farmers who ultimately choose to adopt and implement agroforestry. We construct an empirical soil conservation index as a weighted average of farmer perceptions of four soil attributes and develop a statistical model of soil conservation benefits of agroforestry by using survey data from the Philippines. Accounting for self-selection bias, we evaluate the soil conservation benefits by testing the correlation between the index and the level of agroforestry adoption. Our estimated model shows that agroforestry can generate 15-20 percent soil conservation for the typical small farmer. We offer several methodological, practical, and policy insights. Because many farmers in developing countries face informational and capital constraints, our study suggests that public policies should support smallholder agroforestry, a type of “natural investment” in soil capital, to generate private and public benefits.     

Improving adoptability of farm forestry in the Philippine uplands: a linear programming model

In the Philippines, smallholder farmers have become major timber producers. But the systems of timber production practiced have several limitations. In intercropping systems, the practice of severe branch and/or root pruning reduces tree-crop competition and increases annual crop yields, but is detrimental to tree growth and incompatible with commercial timber production. In even-aged woodlots, lack of regular income and poor tree growth, resulting from farmers’ reluctance to thin their plantations, are major constraints to adoption and profitable tree farming. In the municipality of Claveria, Misamis Oriental, the recent practice of planting trees on widely spaced (6–8 m) contour grass strips established for soil conservation suggests ways to improve the adoptability (i.e., profitability, feasibility and acceptability) of timber-based agroforestry systems. Assuming that financial benefits are the main objective of timber tree farmers, we develop a simple linear programming (LP) model for the optimal allocation of land to monocropping and tree intercropping that maximizes the net present value of an infinite number of rotations and satisfies farmers’ resource constraints and regular income requirements. The application of the LP model to an average farmer in Claveria showed that cumulative additions of widely spaced tree hedgerows provides higher returns to land, and reduce the risk of agroforestry adoption by spreading over the years labour and capital investment costs and the economic benefits accruing to farmers from trees. Therefore, incremental planting of widely spaced tree hedgerows can make farm forestry more adoptable and thus benefit a larger number of resource-constrained farmers in their evolution towards more diverse and productive agroforestry systems.     

What do farmers think? Farmer evaluations of hedgerow intercropping under semi-arid conditions

Results from farmer evaluations of exploratory on-farm trials with hedgerow inter-cropping in a semi-arid region of Kenya (the Yatta Plateau of Machakos District) are presented. Hedgerows ofCassia siamea, Gliricidia sepium andLeucaena leucocephala, which were managed by eight farmers to enhance soil fertility, were established in the mid-1980s. Although trial farmers appear convinced of the ability of the technology to increase crop yields, reduce erosion and provide firewood, most did not feel that the short-term risks (i.e. reduction in crop productivity) and the extra labour required were worth the long-term benefits. Hence, few of the eight farmers were willing to extend their hedges. The discussion suggests that in the risky production environment of the Yatta Plateau, where crop yields fluctuate constantly with the amount of rainfall, soil fertility is not of urgent concern to farmers. A participatory case study approach, which emphasizes farmers' opinions, preferences and ideas elicited through regular farmer evaluation exercises, as distinct from on-farm technology testing for validation, is recommended for on-farm research on new and complex agroforestry technologies. This approach permits between understanding of some of the complex socio-economic factors affecting the adoption of hedgerow intercropping and is the most cost-effective way to gather in-depth and contextual information on farmer decision-making and management of externally introduced agroforestry technologies.     

Impact of contour hedgerows on upland maize yields in the Philippines

An agricultural production function is used to examine the yield impacts of contour hedgerows constructed using double rows of the N₂-fixing species Desmodium rensonii and Flemengia macrophylla. The analysis uses data from a sample of upland Philippine maize farms and controls for input use and plot characteristics. Results support a hypothesis that the long-run impact of hedgerows on maize yields is positive. However, results suggest that in the short run, hedgerows not only reduce area available for cultivation on a plot, but also reduce the performance of corn in the remaining alleys. For newly established hedgerows an increase in hedgerow area is associated with a reduction in maize yield. The time required for hedgerows to compensate for the area they occupy is found to be approximately eight years. This revised version was published online in August 2006 with corrections to the Cover Date.     

Pattern of soil moisture depletion in alley cropping under semiarid conditions in Zambia

The pattern of soil moisture changes was studied during a cropping season in an alley cropping experiment of maize withLeucaena leucocephala andFlemingia macrophylla at the SADC/ICRAF Agroforestry Research Station in a semiarid region near Lusaka, Zambia (28°2956 East and 15°2132 South). Soil moisture potential was monitored at regular intervals using tensiometers installed at 15, 30 and 45 cm depths in fertilized and unfertilized alleys within the double hedgerow, and the first, second and third rows of maize in the alleys.Soil moisture moved mostly towards the top horizon during very dry conditions. Alleys that had received a combination of fertilizer and hedgerow prunings depleted more moisture than those that had only hedgerow prunings. There were no differences in moisture utilization pattern between leucaena and flemingia hedgerows. The hedgerows depleted the same amount of moisture as the maize plants. However, during dry conditions, there was a higher soil moisture content under the hedgerows than in maize rows, indicating that there was no apparent competition for moisture between the hedgerows and the maize plants.     

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.     

Sloping Agricultural Land Technology (SALT): a sustainable agroforestry scheme for the uplands

Soil erosion due to deforestation and heavy rains presents an extremely serious problem in many parts of Southeast Asia, particularly in the upland Philippines. The Mindanao Baptist Rural Life Center (MBRLC), a non-government organization based in the southern part, has developed and spread an agroforestry scheme called Sloping Agricultural Land Technology (SALT) to help control soil erosion and increase crop yields. Basically, SALT utilizes nitrogen-fixing trees as soil binder, fertilizer generator, and livestock feed source. The system also includes annual and perennial diversified food crops grown in the spaces between the hedgerows. The SALT model has been tested both in demonstration plots and farmers' fields, and has proven to be appropriate for use by typical hilly-land farmers. The system can reduce soil erosion and restore moderately degraded hilly lands to a profitable farming system.     

Adoption of mucuna in the farming systems of northern Honduras

In many parts of Central America long fallow periods are no longer feasible due to increasing land pressures. Farmers in northern Honduras have developed and diffused from farmer-to-farmer a maize cropping system using velvetbean (Mucuna spp.) as a short-term fallow. High total annual rainfall in a bimodal distribution is favorable to the system because it allows the completion of two rainfed cropping cycles annually. The first season is dedicated to the production of the mucuna crop and the second season is dedicated to maize. Soil pH and exchangeable Ca were not reduced during a 15-year period of continuous mucuna use. Soil organic matter, infiltration, and porosity increased with continuous mucuna use. Maize yields in fields with continuous rotation of mucuna were on average double those obtained without mucuna. The mucuna system was more profitable than the existing alternative bush-fallow system due to higher returns to land and labor resulting from higher yields, lower weeding and land preparation costs, and reduced risk of drought stress. The relative profitability of the mucuna system was also enhanced by seasonally high maize prices during the second season when maize is harvested in the mucuna system. Relatively easy access to land through inexpensive land ownership and land rental markets has made it possible for even small-scale farmers to dedicate land to the mucuna system. Land-use intensity is increasing in the region, however, as land is converted to pastures for cattle production. The opportunity costs of keeping land in the mucuna system, while also accessing land for first-season maize and other crops, are also increasing. These experiences remind us that a viable livelihood is the primary factor in farmers' decision making about adoption particular components of farming systems.This revised version was published online in November 2005 with corrections to the Cover Date.     

Agroforestry Systems as Alternative Land-Use Options in the Arid Zone of Thal,Pakistan

Agroforestry offers unique opportunities for increasing biodiversity, preventing land degradation, and alleviating poverty, particularly in developing countries, but factors explaining the adoption by farmers are not well understood. A survey of 524 farm households was conducted in Bhakkar district of Punjab, Pakistan to study factors that determine the adoption of agroforestry on the sand dunes in the resource-deficient region of Thal. Two types of agroforestry systems were studied: intercropping and border cropping (also known as boundary or perimeter planting). Both agroforestry systems included irrigated cultivation of the timber trees Eucalyptus camaldulensis (local name: sufeda) and Tamarix aphylla (local name: sars) with wheat, chickpeas (Cicer arietinum) (local name: chana) or cluster beans (Cyamous tetragocalobe) (local name: guars). The majority of the farmers was in favour of intercropping and border cropping. Most farmers reported the protection of nearby crops from dust storms as the most important positive perception about both agroforestry systems. Age, education, and farm to market distance were significant determinants of agroforestry adoption. Older and less-educated farmers, with farms closer to markets were less likely to adopt tree planting or border cropping in Thal. In general, the agroforestry systems examined were more likely to be adopted by farmers who can wait 3–4 years for harvesting crop outputs, but not by poorer farmers who are totally dependent on subsistence agriculture and cannot afford the high initial cost of agroforestry establishment, nor can they wait for crop output for extended periods. Furthermore, the adoption of both agroforestry systems was more likely in remote marginal areas than in areas close to markets. To increase agroforestry adoption rates, government policies should strengthen farmers’ knowledge of every stage of agroforestry through extension services, focusing particularly among the prime prospects, i.e. farmers who will be most likely to adopt agroforestry. Once the prime prospects have adopted it, the older, less-educated, and poor farmers of the rural population can be also focused on to motivate adoption.     

Priority setting in research for sustainable land use: the case of the Adja Plateau,Benin

TheProjet Recherche Appliquée en Milieu Réel is situated on the Adja Plateau, Southwest Benin. The project is responsible for a FSR&D programme that aims at sustainable use of the so-calledTerres de barre. Technologies tested in this context include seasonal fallowing, usingMucuna pruriens cv. group Utilis (weed control, green manure), planted fallows using fast-growing species such asAcacia auriculiformis and hedgerow intercropping systems (various woody auxiliary species). In this paper the local farming system is analyzed to identify key parameters that determine the possibilities for technology adoption. Parameters include: function and history of fields; tenureship; the field's position with regard to fertility flows in the farming system.The paper also aims at understanding the reasons behind low crop yields, in this case maize. An analysis of the soil's chemical fertility, using a computer-based fertility assessment model and data from literature, shows some anomalies with respect to the availability of nutrients from organic matter. Data presented on the use of green manures and oil palm fallow compared to cultivated fields make it likely that organic matter management is a crucial factor in sustainable use of these soils (maintenance of soil structure and soil life). Given key parameters, a matrix is used to determine potential niches in the farming system for the various biomass production technologies mentioned previously, including the locally developed planted fallow based on oil palm.     

The impact of alley cropping Gliricidia sepium and Cassia spectabilis on upland rice and maize production

G. sepium and C. spectabilis hedgerows were established on slopes ranging from 18 to 31% in an effort to reduce soil erosion and improve upland rice and maize production. Upland rice and maize responded more to soil incorporated G. sepium biomass than to mulched, C. spectibilis. Incorporating hedgerow biomass equivalent to over 40 kg N per hectare, however, did not increase upland rice productivity. Maize, planted during the drought-prone second season, responded more than did rice to mulching. Crop performance improved along the slope gradient. Hedgerow-crop competition was observed at the upper and lower interfaces. Terracing intensified hedgerow-crop competition at the upper interface by reducing the crop's effective rooting depth. Under prevailing climatic and soil conditions, mixed hedgerows of C. spectabilis and G. sepium initially produced approximately 7 tons of fresh biomass per hectare every 3 months. Four years after hedgerow establihment, however C. spectabilis biomass was chlorotic and considerable mortality was observed, suggesting that C. spectabilis may be depleting soil N reserves.     

The household economics of rubber intercropping during the immature period in Northeast Thailand

In order to alleviate poverty in Northeast Thailand, the Thai government has promoted rubber farming, which has expanded at the expense of annual crops. Because of a long immature period, planting rubber represents a loss of income for poor farmers in the very first years. This paper analyzed how rubber intercropping during the immature period helps farmers to compensate for this loss of income. Economic performances of the most widespread rubber farming systems were analyzed using information collected from a questionnaire addressed to 35 farmers in Buriram province. A sub-sample of 22 farmers was further interviewed to estimate the contribution of rubber intercropping in the formation of the total annual income during the immature period. The results showed that interest in rubber intercropping has grown, with cassava and rice as the main associated crops. With additional costs of about 14,169 ?/ha/year over monospecific rubber plantations, rubber-cassava intercropping systems generated a gross margin estimated at 11,340 ?/ha/year for a 3-year period. Compared to a monospecific rubber plantation, rubber-cassava intercropping systems reduced management costs by 59% over the 6-year period of rubber immaturity. The cash-income drawn from intercropping ranged from 0 to 26.8% of the household’s total annual income, which can be of considerable importance for low-income farmers.