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.     

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.     

Tree Culture of Smallholder Farmers Practicing Agroforestry in Gunung Salak Valley,West Java,Indonesia

This paper investigates the types of agroforestry system that exist in Gunung Salak Valley, West Java, Indonesia in order to characterize the differences in their basic structure and associated crop plant diversity. Data were collected through rapid rural appraisal, field observation and focus groups, followed by household survey of a sample of 20 agroforestry farmers. Five main agroforestry systems (homegardens, fruit tree system, timber tree system, mixed fruit–timber system, and cropping in the forest understory) exist in the study area, and all of them exhibit a noticeable diversity in terms of both species composition and utilization. Products from farming accounted for an average 24 % of household income. They comprised agroforestry products which contributed IDR 3.25 million/year and other agricultural products contributing IDR 1.66 million/year. The observed agroforestry systems include not only a form of forest dominated by ‘cultivated trees’, but also an anthropogenic vegetation formation derived from agricultural antecedents. In land-use classifications agroforestry systems are not recognized as forestry, but like forests they provide tree products and services. Classification will always be disfunctional if a binary system is applied, thus a more sophisticated approach should be adopted that incorporates the economic and environmental characteristics of a wider range of systems.     

Adequate design of control treatments in long term agroforeestry experiments with multiple objectives

Agroforestry experiments usually include control plots of either pure crop or pure tree stands. A clear distinction should be made between intensively managed biophysical controls and farming system controls with realistic labour input and management regimes. Trying to draw biophysical conclusions from farming system controls (or the reverse) is often not justifiable. The design and management of these elusive control plots is a complicated issue which is often overlooked. Many factors beyond the control of the experiment manager can disturb long term field agroforestry experiments. Some examples from French agroforestry experiments illustrate how uncontrolled factors may bias the results, including the proportion of harvested to planted trees, the weeding regimes, and the use of tree- shelters. The analysis of agroforestry data could be more efficient when considering a continuum of tree – crop mixture management options between the agroforestry plot and the non agroforestry plot. The concept of biophysical control plots becomes then less essential. A relevant modelling approach of interactions between trees and crops should 1) perform correctly for any tree/crop proportion and even for pure stands, when setting the parameters of the other component to zero, 2) provide for the inclusion of new, uncontrolled factors that could emerge through time. The biological efficiency of agroforestry systems may however be a subordinate criterion for agroforestry adoption, as observed at the moment in France. Agroforestry systems with poor biological outcomes can even be very attractive in some ecological or sociological conditions, and only farming system controls may bring this aspect to light. This revised version was published online in June 2006 with corrections to the Cover Date.     

Integrated indicators for performance assessment of traditional agroforestry systems in South West Cameroon

Farming Systems developed in Humid Tropical Zones are frequently characterized by a combination of perennial and annual plants, intermixed in complex tree-crop associations. The productive functioning, the agronomic and economic performances, and the sustainability of these crop associations remain poorly understood. To improve the management capacity of these complex agroforestry systems, adequate indicators must be developed and integrated in assessment systems. These may then be used to aid farmers, assisted by their extension agents, in making decisions regarding management practices. The present study focused on the agroforestry systems developed by 38 farmers in the South West Region of Cameroon, which were surveyed for a large set of variables, aiming at formulating a Traditional Agroforestry Performance Indicators System (TAPIS). Analyses of the relationships among indicators in TAPIS allowed an improved understanding of agro-ecological and agro-economic performances in the studied plots, revealed tradeoffs regarding plant stand, income generation, food production, input demands and work requirements; and may contribute to the sustainability assessment of agroforestry systems.     

Crop commercialization and adoption of gum-arabic agroforestry and their effect on farming system in western Sudan

Increasing trend in the sole crops commercialization has questioned the sustainability of the traditional gum Arabic agroforestry (Bush-fallow) system in western Sudan. This shift in the farming system from a traditional sustainable system to more commercialized one has resulted in a drastic decline in soil fertility, decreased crop productivity and low gum Arabic production. Therefore, identification of alternative options and incentives are required to ameliorate the negative environmental effects of increasing commercialization trends. This paper takes this issue and empirically investigating the factors influencing the decision to adopt agroforestry using a binary probit model. The results show that farmers with less commercialization, access to credit, less fragmented land, more education, high gum Arabic gate price, located away from the markets, and with more years of experience in farming are more likely to practice the traditional gum Arabic agroforestry system. In contrast, the allocation of more working days for commercial sole crops production, more fragmented land, and higher commercialization index reduces the probability of gum Arabic agroforestry adoption. In conclusion, this dichotomy between sole crop commercialization and traditional gum agroforestry system may be solved through the encouragement of the adoption of the traditional intercropping system with gum tree (Acacia senegal). Production of gum tree (Acacia senegal) itself should be more commercialized and prioritized. Conservation programs should focus on more educated, experienced famers with less fragmentized land if the policy is to promote the sustainable farming system in the region to promote soil fertility and to improve the effect of sole crop commercialization on traditional gum Arabic agroforestry system.     

Adoption of On-Farm Tree Planting in Kibaale District,Western Uganda

Using logistic and multiple regression analyses, this article examines the socioeconomic factors that influence farmers’ decisions to adopt on-farm tree planting, one of the agroforestry techniques promoted by government agencies and research institutions for use in the farming systems of Uganda. A household survey involving 200 farmers was carried out in the Subcounties of Kabamba, Mugarama, Kagadi, and Kiryanga in Kibaale District, western Uganda. From the analyses, we found out that a farmer's decision to adopt on-farm tree planting is influenced by household and field characteristics. Gender, tree tenure security, availability of seed and supply, guidance by extension and research Institutions, size of landholding per household, fuelwood scarcity, and main source of family income were the factors that significantly influenced the decision to adopt on-farm tree planting. We recommended that in order to promote increased adoption of on-farm tree planting, appropriate socioeconomic characterization should be explored in order to target areas with better adoption potential for optimal realization of the intended objectives by government agencies and research institutions.     

Evolution of agroforestry based farming systems: a study of Dhanusha District, Nepal

This paper examines how agroforestry-based farming systems evolved in the Dhanusha district of Nepal following the conversion of forest into agriculture during the early 1950s. Some data are from two focus group discussions with agroforestry farmers and one meeting with agroforestry experts. The farmers?? discussion traced the development of farming practices from 1950 to 2010 to identify the drivers of land use change. The experts?? discussion resulted in a scale to differentiate the prevailing farming systems in the study area considering five key components of agroforestry: agricultural crops, livestock, forest tree crops, fruit tree crops and vegetable crops. Data related to the system components were collected from the randomly selected households. The study reveals that land use had generally changed from very simple agriculture to agroforestry, triggered by infrastructure development, technological innovations, institutional support (subsidies and buy-back guarantees) and extension programs. A range of farming systems with varying degrees of integration was evident in the study area: simple agriculture; less integrated agroforestry; semi-integrated agroforestry and highly integrated agroforestry. The three types of agroforestry systems, which are the focus of this study, varied significantly in terms of farm size, cropping intensity, use of farm inputs, tree species diversity, tree density, home to forest distance and agricultural labour force.     

Incorporating economic risk aversion in agroforestry planning

The ability to use a knowledge of past market price fluctuations to reduce the risk of future financial returns is explored in the context of planning an agroforestry system with a cash crop component. It is demonstrated that if past crop price behavior is indicative of future price behavior, planting crops with stable and/or negatively correlated net revenues can reduce the variance of future net revenues and hence decrease the financial risks of agroforestry systems.This research was supported by the Utah Agricultural Experiment Station, Utah State University, Logan, Utah 84322-4845. Approved as journal paper no 3903.     

Determinants of farmers' adoption and adaptation of alley farming technology in Nigeria

Understanding the factors affecting framers' adoption of improvedtechnologies is critical to success of implementing agroforestry developmentprograms. This paper evaluated the determinants of farmers' decisions to adoptand adapt alley farming technology and its variants in the farming systems ofNigeria, using econometric Logit models. Eleven variables were significant inexplaining farmers' adoption decisions. The model results show that farmercharacteristics that influenced adoption included the gender of the farmer,contact with extension agents, years of experience with agroforestry and tenancystatus in the village. Economic factors, proxied by village-levelcharacteristics that condition resource use incentives, were also significant.These variables include the extent of village land pressure, extent of erosionintensity, village fuel wood pressure, importance of livestock as an economicactivity in the village and the distance of the village locations from urbancenters. The paper showed that farmers are already making significantmodifications to the conventional alley farming technology introduced byscientists. The two most important modifications were the introduction of fallowperiods into the conventional system and changes in the pruning regime of thesystem. Model results showed that human capital variables were significant inexplaining farmers' decisions to adapt and modify the technology. Farmereducation and family size significantly influence the choice of pruning regime.Farmers' age, education, intensity of erosion in the farmers' village, andfarmers' land availability significantly influence whether or not fallowperiod is introduced into the conventional system. To promote greater adoptionof agroforestry alternatives to slash-and-burn agriculture, particular attentionshould be placed on the use of appropriate socioeconomic characterization, tobetter target technologies to areas with higher adoption potential. This revised version was published online in June 2006 with corrections to the Cover Date.     

Cocoa-based agroforestry system dynamics and trends in the Akongo subregion of central Cameroon

Cocoa is a major crop and income source for most farmers and rural households in the Centre, South and South-West regions of Cameroon, where cocoa is generally produced in agroforestry systems. In this country, cocoa-based agroforestry systems (CBAFS) are undergoing multiple changes alongside the rapid changes underway in the natural, economic and socio-political conditions. This study—carried out in the Akongo subregion in central Cameroon—was designed to gain insight into the CBAFS trends and dynamics in the light of those multiple changes. This semi-structured socioeconomic survey involved interviews and direct observations at plot, farm, household and village scales. Overall, forty cocoa growers from ten villages were interviewed and then fifteen cocoa plots were characterized on the basis of the survey findings. They revealed that cocoa was the major crop in this study area, with cocoa plantations occupying three quarters of the total farming area. Three types of CBAFS were identified, which differed according to their vegetation structure, management practices and age of the plantations. Dynamics affecting the structural characteristics and the spatial extension of these systems emerged and were intimately linked to the dynamics of the cocoa farmer population in relation to their context.

     

Linking on-station research with on-farm testing: The case of agroforestry and organic matter-based cropping systems for the Rwanda farming systems improvement project

Hillside farming with its attendant erosion and decline in soil fertility is common-place in the area served by the Farming Systems Improvement Project. The project is designing land-use systems that would check erosion, increase soil organic matter and restore soil fertility. These systems will allow small farmers to increase or maintain product long-term basis without resorting to the use of high doses of inorganic fertilizers which are not readily available in the country. The use of leguminous shrubs and cover crops as nutrient sources — concepts embodied in agroforestry and organic farming systems — are options that landuse experts think might solve the problem. However, there is a dearth of knowledge about the biological feasibility of these interventions in the project area. This paper reports how FSIP combined problem diagnosis and analysis, researcher-managed adaptive trials and a field day to attack this lack of information. The rationale for using this approach is to address farmers' real needs, save time and minimize risk to poor farmers. This article is a contribution from the University of Arkansas' USAID-supported Farming System Improvement Project (FSIP) in Rawanda (USAID 696-0110), B.P. 625, Kigali, Rawanda. Authors are the project's soil scientist/agronomist and its extension and training specialist respectively.     

Innovation in input supply systems in smallholder agroforestry: seed sources,supply chains and support systems

Institutional innovation in providing inputs and services is a central element for smallholder development. Agroforestry is an important income generating activity for millions of smallholders in the tropics, yet access to quality planting material—germplasm—of valuable tree species remains a major hurdle for improving farm productivity. We discuss requirements and possibilities for institutional innovation in developing more efficient delivery systems for tree germplasm as one aspect of improved input supply. We describe a simple model for delivery to farmers that identifies the major types of germplasm sources and discuss how this model can be used to identify relevant interventions to address bottlenecks in current systems. Our analysis leads to eight input supply configurations for smallholder agroforestry, typified by three major models. Lessons from the evolution of smallholder crop seed delivery systems can be applied to tree germplasm supply and indicate that a commercial, decentralised model holds most promise for sustainability. However, current emphasis in agroforestry on government and NGO models of delivery hinder the development of this approach. The application of prevailing classification approaches may also create a barrier to the development of appropriate supply systems that effectively service smallholders. An important implication of our analysis is that current actors in agroforestry input supply systems must redefine their roles in order for effective delivery to take place. We chose a case study from Kenya to illustrate our points.     

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.     

Linking on-station research with on-farm testing: The case of agroforestry and organic matter-based cropping systems for the Rwanda farming systems improvement project

Hillside farming with its attendant erosion and decline in soil fertility is common-place in the area served by the Farming Systems Improvement Project. The project is designing land-use systems that would check erosion, increase soil organic matter and restore soil fertility. These systems will allow small farmers to increase or maintain product long-term basis without resorting to the use of high doses of inorganic fertilizers which are not readily available in the country. The use of leguminous shrubs and cover crops as nutrient sources — concepts embodied in agroforestry and organic farming systems — are options that landuse experts think might solve the problem. However, there is a dearth of knowledge about the biological feasibility of these interventions in the project area.This paper reports how FSIP combined problem diagnosis and analysis, researcher-managed adaptive trials and a field day to attack this lack of information. The rationale for using this approach is to address farmers' real needs, save time and minimize risk to poor farmers.This article is a contribution from the University of Arkansas' USAID-supported Farming System Improvement Project (FSIP) in Rawanda (USAID 696-0110), B.P. 625, Kigali, Rawanda. Authors are the project's soil scientist/agronomist and its extension and training specialist respectively.     

Nutrient cycling in an agroforestry system with runoff irrigation in Northern Kenya

A nutrient balance was determined for sole and alley cropped Sorghum bicolor and Acacia saligna in a runoff irrigation system in Northern Kenya. Nutrient input including precipitation and runoff, and output through harvest and leaching were measured for N, P, K, Ca and Mg using adsorption resins, tensiometry and suction cups. Various management scenarios are discussed with respect to nutrient return. Nutrient input with rainfall was generally low in comparison to nutrient uptake or leaching losses. The irrigation water, however, constituted an important nutrient input, especially for Ca and Mg. Nutrient export with the harvest was large for N and K, but can effectively be reduced by a nutrient return with mulch. Nutrient leaching losses from the topsoil (0–30 cm) were lower in the sorghum monoculture than in the tree-based systems. In the subsoil (120 cm), however, leaching was effectively reduced by the trees. In the agroforestry system, leaching losses of N under the sorghum were 53% lower than in the sorghum monoculture. This could be attributed to a higher root abundance and a higher ratio of nutrient uptake-to-leaching in the agroforestry system than in the monocultures indicating a higher nutrient efficiency. The lower leaching losses in the agroforestry system compared to the crop monoculture could not compensate for the additional nutrient export in tree biomass. A nutrient return by mulching crop residues and acacia leaves was essential for a positive nutrient balance in the agroforestry system. Combining annual and perennial crops provided a higher internal nutrient cycling than the monocultures. This revised version was published online in June 2006 with corrections to the Cover Date.     

Reducing financial risk in agroforestry planning: a case study in Costa Rica

We used fluctuations in net income from alternative cropping systems to assess the financial risk associated with an agroforestry system. Mean-variance analysis was used to derive a set of minimum-risk farm plans for a 15-hectare farm in Costa Rica. Monocultural coffee production provided the highest expected net income, but also had the greatest economic risk. As risk was reduced, the optimal agroforestry system diversified to include other cropping systems in addition to the coffee monoculture. Risk aversion was, however, accompanied by significant reductions in expected net income for the cropping systems studied. The inclusion of additional cropping systems whose net incomes are negatively correlated with the systems considered here could help reduce the economic risk facing rural agriculturalists in this region.This research was supported by the Utah Agricultural Experiment Station, Utah State University, Logan, Utah 84322-4845. Approved as journal paper no. 4211.     

Plant-soil interactions in multistrata agroforestry in the humid tropicsa

Multistrata agroforestry systems with tree crops comprise a variety of land use systems ranging from plantations of coffee, cacao or tea with shade trees to highly diversified homegardens and multi-storey tree gardens. Research on plant-soil interactions has concentrated on the former. Tree crop-based land use systems are more efficient in maintaining soil fertility than annual cropping systems. Certain tree crop plantations have remained productive for many decades, whereas homegardens have existed in the same place for centuries. However, cases of fertility decline under tree crops, including multistrata agroforestry systems, have also been reported, and research on the causal factors (both socioeconomic and biophysical) is needed. Plantation establishment is a critical phase, during which the tree crops require inputs but do not provide economic outputs. In larger plantations, tree crops are often established together with a leguminous cover crop, whereas in smallholder agriculture, the initial association with food crops and short-lived cash crops can have both socioeconomic and biological advantages. Fertilizers applied to, and financed by, such crops can help to `recapitalize' soil fertility and improve the development conditions of the young tree crops. Favorable effects on soil fertility and crop nutrition have been observed in associations of tree crops with N<sub>2</sub>-fixing legume trees, especially under N-deficient conditions. Depending on site conditions, the substitution of legume `service' trees with fast-growing timber trees may lead to problems of competition for nutrients and water, which may be alleviated through appropriate planting designs. The reduction of nutrient leaching and the recycling of subsoil nutrients are ways to increase the availability of nutrients in multistrata systems, and at the same time, reduce negative environmental impacts. These processes are optimized through fuller occupation of the soil volume by roots, allowing a limited amount of competition between associated species. The analysis of temporal and spatial patterns of water and nutrient availability within a system helps to optimize the use of soil resources, e.g., by showing where more plants can be added or fertilizer rates reduced. Important research topics in multistrata agroforestry include plantation establishment, plant arrangement and management for maximum complementarity of resource use in space and time, and the optimization of soil biological processes, such as soil organic matter build-up and the stabilization and improvement of soil structure by roots, fauna and microflora. This revised version was published online in June 2006 with corrections to the Cover Date.