Agroforestry systems recover tree carbon stock faster than natural succession in Eastern Amazon,Brazil

Agroforestry Systems - The potential of agroforestry systems (AFS) for atmospheric carbon sequestration in degraded tropical lands is of key interest for climate change and rural development...     

<Emphasis Type="Italic">Cinderella</Emphasis> agroforestry systems

The underlying principles and traditional knowledge concerning indigenous agroforestry systems (AFS) around the world have been used successfully in the design of improved systems; but lately there has been a slow-down in that effort. Recognizing that Cinderella, by analogy, refers to an individual whose attributes were unrecognized or one who unexpectedly achieved success after a period of obscurity and neglect, we propose Cinderella agroforestry systems for such underexploited and “forgotten” AFS. In order to highlight their unrecognized potentials, a few such systems that are location-specific and little-known outside their areas of existence were selected from around the world. Each selected system is unique in terms of its production, environmental, and sociocultural attributes; but none had been described in quantitative terms of ecology and production. A qualitative SWOT (strengths–weaknesses–opportunities–threats) analysis of the systems showed several commonalities among them. While sustainability, multi-functionality, and high sociocultural values are common strengths, low levels of production and lack of research- and technology inputs to improve the system are the major weaknesses. The opportunities emanating from strengths and weaknesses are also common to all the systems; and “threats” to these systems arise mostly from ramifications of government policies. Given the acknowledged role of AFS in climate-smart agriculture and the current global momentum for working with communities to better manage landscapes, learning from success stories of the Cinderella AFS could suggest models for sustainable development, and efforts in that direction should also be incorporated into global agroforestry research agendas.     

Agroforestry Impacts on Soil Fertility in the Rima'a Valley,Yemen

Yemen is one of the world's least developed countries and experiences problems of scarcity of natural agricultural resources as well as soil erosion and degradation. Agroforestry systems (AFS) are being promoted as a more appropriate land use system than monocropping systems (MCS) worldwide. Unfortunately, long-term studies on agroforestry and other land use systems (LUS) do not exist in Yemen. Agroforestry in the Rima'a region has started to deteriorate and many farmers turned to (MCS). This study was conducted in the Rima'a Valley, near Alsharq town, Dhamar, Yemen. The study evaluates the soil nutrients, organic matter (OM), and other soil properties such as pH, bulk density, and porosity under AFS and compares it with soil under MCS. Standard procedures for soil sampling and analyzing were used to collect and analyze 36 composite samples from Site 1 and 36 composite samples from Site 2 from six cropping systems (treatments). The results showed that there were significant variations in relation to LUS. Agroforestry practices—mixed trees with coffee (S1), and Cordia africana L. with coffee (S2) have higher nitrogen concentration (0.17–0.26%) as compared to the Ziziphus spina-christi L. with maize (S3) and the monocropping maize (S5), (<0.16% in both Sites 1 and 2). Similar results were seen on the effect of the different LUS on the soil P, K, and OM contents at the two sites (p < .01). While soil N, P, and soil K were higher under agroforestry systems S1, and S2 in both sites, it was the lowest in S5 in both sites. It can be concluded that agroforestry has more favorable effects on soil fertility and other soil properties. The government should establish programs and campaigns to disseminate AFS technology and promote the importance of agroforestry in soil conservation.     

Policy and institutional support for agroforestry: an analysis of two Ecuadorian case studies

Institutional and policy issues are now recognized as high priority items in agroforestry research. However, such studies based on actual field experiences seldom seem to have been undertaken. To help address this deficiency, a study was undertaken in Ecuador to evaluate institutional and policy impacts on agroforestry dissemination using two field projects as case studies.The projects were in contrasting ecological locations: the Amazonian lowlands (the Coca Agroforestry Project), and the Andean highlands (the PROMUSTA project). The impact of policy and institutional constraints (such as land tenure, research and extension support, marketing and pricing, and credit) on the implementation of these projects was assessed based on interviews with farmers and project officials as well as analyses of secondary data. The Coca project was found to be adversely impacted by the lack of extension, product marketing, and credit availability. The principal institutional constraints for the Andean project included legal obstacles to farm-land procurement, inadequate extension, little state-financial assistance, and limited affordable credit. The relevance of these issues was location specific: while access to land was not a serious constraint in the lowlands, it was a major issue in the highlands.The study validates the premise that policy and institutional evaluations should become an essential component of design and implementation of agroforestry projects. Although the components of a sound policy framework might be similar in most developing-country situations, it may not be possible to evolve universally applicable procedures for agroforestry-policy formulation because of the location-specificity of the promoted systems and the institutional issue related to their adoption.Florida Agricultural Experiment Station Journal Series No. R-03861.     

Integrating belowground carbon dynamics into Yield-SAFE,a parameter sparse agroforestry model

Agroforestry combines perennial woody elements (e.g. trees) with an agricultural understory (e.g. wheat, pasture) which can also potentially be used by a livestock component. In recent decades, modern agroforestry systems have been proposed at European level as land use alternatives for conventional agricultural systems. The potential range of benefits that modern agroforestry systems can provide includes farm product diversification (food and timber), soil and biodiversity conservation and carbon sequestration, both in woody biomass and the soil. Whilst typically these include benefits such as food and timber provision, potentially, there are benefits in the form of carbon sequestration, both in woody biomass and in the soil. Quantifying the effect of agroforestry systems on soil carbon is important because it is one means by which atmospheric carbon can be sequestered in order to reduce global warming. However, experimental systems that can combine the different alternative features of agroforestry systems are difficult to implement and long-term. For this reason, models are needed to explore these alternatives, in order to determine what benefits different combinations of trees and understory might provide in agroforestry systems. This paper describes the integration of the widely used soil carbon model RothC, a model simulating soil organic carbon turnover, into Yield-SAFE, a parameter sparse model to estimate aboveground biomass in agroforestry systems. The improvement of the Yield-SAFE model focused on the estimation of input plant material into soil (i.e. leaf fall and root mortality) while maintaining the original aspiration for a simple conceptualization of agroforestry modeling, but allowing to feed inputs to a soil carbon module based on RothC. Validation simulations show that the combined model gives predictions consistent with observed data for both SOC dynamics and tree leaf fall. Two case study systems are examined: a cork oak system in South Portugal and a poplar system in the UK, in current and future climate.     

Finding alternatives to swidden agriculture: does agroforestry improve livelihood options and reduce pressure on existing forest?

Swidden cultivation can contribute to deforestation and land degradation, which can subsequently result in a number of serious environmental problems. This paper examines the economic and social potential of agroforestry systems and the barriers to their widespread adoption, as a land use alternative to swidden cultivation, which may potentially help protect local forest. The Gunung Salak valley in West Java, Indonesia is presented as a case study. Based on farmers’ and experts’ assessment, costs and benefits have been estimated, which show that the two investigated agroforestry systems have higher net present value and benefit-cost ratio (B/C) than the two swidden cultivation systems. Tree ownership also creates more permanent rights to farmland and is prestigious in the community. Agroforestry products (fruit, vegetables etc.) have high monetary value and help strengthen social cohesion when shared with neighbors. However, farmers are reluctant to implement agroforestry. Stated reasons are related to both culture and capacity. Farmers practicing agroforestry are less involved in forest clearing and forest products collection than swidden farmers indicating that it may contribute positively to conservation of local forests. Increasing the adoption of agroforestry farming in the study area will require support to overcome capacity constraints.     

The use and value of multiple methods to capture the diversity of endogenous agroforestry knowledge: an example from Rwanda

To understand endogenous agroforestry knowledge and the processes behind the generation of such knowledge, multiple methods are needed. In this paper, the identification and characterization of farmer agroforestry experts will illustrate the necessity of multiple methods. Nonformal, participatory methods were employed to identify the research subjects (farmer agroforestry experts) and to gain insights into the emic conception and understanding of ‘knowledge’ and ‘agroforestry’. An adaptation of the wealth ranking game was used to determine (1) the research subjects using locally defined criteria of ‘being knowledgeable about agroforestry’, and (2) how this knowledge is distributed within a community. Additional information, approaching the subject from an etic perspective, was gathered using formal surveys to collect socioeconomic data and to make an inventory of all trees and tree species. Study results indicate that exclusive reliance on either emic or etic perspectives would not have yielded satisfactory results, as there is a differentiation in agroforestry knowledge and agroforestry systems between different groups of farmers. It is, therefore, recommended that future studies of endogenous knowledge systems combine qualitative and quantitative, participatory and formal data collection methods as they provide complementary and supplementary perspectives on a complex reality.     

Local tree knowledge can fast-track agroforestry recommendations for coffee smallholders along a climate gradient in Mount Elgon,Uganda

Arabica coffee (Coffea arabica) is economically important for many smallholder farmers in the Mount Elgon region of East Uganda, but its production is increasingly threatened by climate change. However, ecosystem services (ES) provided by companion trees in coffee agroforestry systems (AFS) can help farmers adapt to climate change. The objectives of this research were to develop agroforestry species recommendations and tailor these to the farmers’ needs and local context, taking into consideration gender. Local knowledge of agroforestry species and ES preferences was collected through farmer interviews and rankings. Using the Bradley-Terry approach, analysis was done along an altitudinal gradient in order to study different climate change scenarios for coffee suitability. Farmers had different needs in terms of ES and tree species at different altitudes, e.g. at low altitude they need a relatively larger set of ES to sustain their coffee production and livelihood. Local knowledge is found to be gender blind as no differences were observed in the rankings of species and ES by men and women. Ranking species by ES and ranking ES by preference is a useful method to help scientists and extension agents to use local knowledge for the development of recommendations on companion trees in AFS for smallholder farmers.     

An approach to developing methodologies for evaluating agroforestry systems in India

India has a long tradition of agroforestry and many different types of indigenous agroforestry systems can be found in different parts of the country. Most of these systems are, however, very location-specific, and information on them is mostly anecdotal. Therefore, their benefits have remained vastly underexploited. The situation is now slowly but steadily changing. It has now been well recognized that agroforestry can address some of the major land-use problems of rainfed farming systems, and that a great deal can be accomplished by improving the indigenous systems. However, agroforestry research is still in its infancy; most of the on-going efforts are of the “WHAT” type dealing with component and system management, with too little attention being paid to the “WHY” (reasons for the observed behavior) and the “HOW” (processes involved) of the results. Therefore, most of the research results obtained from such efforts are also largely location-specific. In order to improve the efficiency of indigenous agroforestry systems, as well as to assess the performance of improved technologies, we need to have a systematic procedure to evaluate such systems. Since productivity, sustainability and social acceptability are the key attributes of all agroforestry systems, evaluation procedures should encompass all these criteria. But the precise criteria for such evaluations have still not been fully developed. A broad evaluation of the indigenous agroforestry systems and current research efforts in India shows that the thrusts of agroforestry efforts are different in different agro-ecological regions depending on the region's characteristic land-use constraints. Therefore it should be possible to develop an evaluation matrix of agro-ecological regions versus agroforestry potentials and attributes. Such a matrix could be a framework for evaluating agroforestry systems, as well as a guide for the type of research and nature of data that will need to be generated from agroforestry projects. The matrix with necessary adjustments can be made use of for agroforestry systems evaluation within relatively smaller areas such as sub-regions to larger areas such as states, or zones consisting of several states. The results of such evaluations can be thses for appropriate extension recommendations for that specific area or region.     

Multipurpose tree yield data — their relevance to agroforestry research and development and the current state of knowledge

Agroforestry is not likely to be accepted, particularly by small-holders, unless it is proved superior to other forms of land use not only on ecological but also on economic grounds. It is therefore argued that economic parameters concerning the quantitative productivity of all agroforestry systems components have to be a matter of concern to both research and development in agroforestry.In the process of screening selected relevant literature and as a result of a search of ICRAF's Multipurpose Tree and Shrub Data Case, the yawning gap between the high level of knowledge on agricultural crops on the one hand and the low level on woody perennials on the other is exposed as a serious obstacle to the analysis of agroforestry systems and to the further development of agroforestry. The lack of knowledge on woody perennials, as substantiated in this paper, concerns particularly quantitative production data on trees and shrubs used in agroforestry systems.It is also argued in support of the views cited from other authors that what little there is by way of yield data on woody perennials is scattered and distributed over a vast amount of literature, and thus often difficult to access and to retrieve, and often difficult if not impossible to compare owing to different methods and parameters employed in attaining the data.Although the difficulties of yield assessment are appreciated, increased efforts to obtain more — and more comparable — data on te productivity of woody perennials are advocated. In support of this call for stepping up appropriate activities some preliminary suggestions are presented on how to standardize parameter of yield assessments to achieve better comparability and how to increase accessibility of yield data and promote retrieval of data by the establishment of supplementary data bases.     

Agroforestry for ecosystem services and environmental benefits: an overview

Agroforestry systems are believed to provide a number of ecosystem services; however, until recently evidence in the agroforestry literature supporting these perceived benefits has been lacking. This special issue brings together a series of papers from around the globe to address recent findings on the ecosystem services and environmental benefits provided by agroforestry. As prelude to the special issue, this paper examines four major ecosystem services and environmental benefits of agroforestry: (1) carbon sequestration, (2) biodiversity conservation, (3) soil enrichment and (4) air and water quality. Past and present evidence clearly indicates that agroforestry, as part of a multifunctional working landscape, can be a viable land-use option that, in addition to alleviating poverty, offers a number of ecosystem services and environmental benefits. This realization should help promote agroforestry and its role as an integral part of a multifunctional working landscape the world over.     

The Bioeconomic Potential for Agroforestry in Australia’s Northern Grazing Systems

Although agriculture generates 16% of Australia’s greenhouse gas emissions, it also has the potential to sequester large quantities of emissions through land use management options such as agroforestry. Whilst there is an extensive amount of agroforestry literature, little has been written on the economic consequences of adopting silvopastoral systems in northern Australia. This paper reports the financial viability of adopting complementary agroforestry systems in the low rainfall region of northern Australia. The analysis incorporates the dynamic tradeoffs between tree and pasture growth, likely forest product yields, carbon sequestration and livestock methane emissions in a bioeconomic model. The results suggest there are financial benefits for landholders who integrate complementary agroforestry activities into existing grazing operations at even modest carbon prices.     

竹和中国的农用林业

作者简要介绍了中国古代传统农用林业经营模式历史的基础上,论述了现代农用林业模式的设计原理和顺序。根据应用竹类植物在营建农用林业模式的重要性,提出了将这类模式命名为竹类农用林业模式,同时对中国竹类农用林业的六种主要模式及其营建技术作了初步探讨,认为竹类农用林业模式是世界上许多国家为解决当前面临众多问题时可采用的一种良好的土地经营体制。     

Directions in tropical agroforestry research: past, present, and future

Reflections on the past two decades of organized research in tropical agroforestry raise several issues. Research efforts started with an inductive and experiential approach but have subsequently followed a deductive and experimental approach that includes hypothesis testing and the development of predictive capability; agroforestry research is thus being transformed into a rigorous scientific activity. The research agenda, so far, has given high priority to soil fertility and other biophysical interactions, less priority to anthropological and sociological aspects, and little priority to evaluating costs and returns, pests and diseases, and the so-called non-timber forest (tree) products. Moreover, larger-spatial-scale issues, such as carbon sequestration, water quality, and biodiversity conservation, have been neglected because of the emphasis on field- and farm-scale studies. Overall, the high expectations that were raised about the role and potential of agroforestry as a development vehicle have not been fulfilled. In order to overcome this, it is imperative that research be focused on the generation of appropriate, science-based technologies of wide applicability, especially under resource-poor conditions and in smallholder farming systems. Future research agendas should entail a judicious blending of science and technology. Applied research should build upon the findings of basic research to generate technologies for application at the farm, regional and global levels. Such research should place increased focus on previously neglected subjects, for example, the exploitation of indigenous fruit-producing trees, the agronomic components of agroforestry systems, and the global issues mentioned above. Furthermore, an appropriate methodology that embodies economic, social, and environmental costs and benefits needs to be developed to realistically assess the impacts of agroforestry, and an enabling policy environment that will facilitate agroforestry adoption needs to be made available. Agroforestry research of the 21st century should strive to build bridges from the inductive phase of the past, through the deductive phase of the present, to the future phase of harnessing science and generating technologies for the benefit of the land and its present and future users. This revised version was published online in June 2006 with corrections to the Cover Date.     

Agroforestry strategies to sequester carbon in temperate North America

Information on carbon (C) sequestration potential of agroforestry practices (AP) is needed to develop economically beneficial and ecologically and environmentally sustainable agriculture management plans. The synthesis will provide a review of C sequestration opportunities for AP in temperate North America and the estimated C sequestration potential in the US. We estimated carbon sequestration potential for silvopasture, alley cropping, and windbreaks in the US as 464, 52.4, and 8.6?Tg?C?yr^?1, respectively. Riparian buffers could sequester an additional 4.7?Tg?C?yr^?1 while protecting water quality. Thus, we estimate the potential for C sequestration under various AP in the US to be 530?Tg?yr^?1. The C sequestered by AP could help offset current US emission rate of 1,600?Tg?C?yr^?1 from burning fossil fuel (coal, oil, and gas) by 33?%. Several assumptions about the area under different AP in the US were used to estimate C sequestration potential: 76?million?ha under silvopasture (25?million?ha or 10?% of pasture land and 51?million?ha of grazed forests), 15.4?million?ha (10?% of total cropland) under alley cropping, and 1.69?million?ha under riparian buffers. Despite data limitation and uncertainty of land area, these estimates indicate the important role agroforestry could play as a promising CO₂ mitigation strategy in the US and temperate North America. The analysis also emphasizes the need for long-term regional C sequestration research for all AP, standardized protocols for C quantification and monitoring, inventory of AP, models to understand long-term C sequestration, and site-specific agroforestry design criteria to optimize C sequestration.     

Contribution of cacao agroforestry versus mono-cropping systems for enhanced sustainability. A review with a focus on yield

The demand for cocoa has increased over the past years following the growth of cocoa-based products linked to the rise in living standard in highly populated countries. Cacao industry is therefore currently facing the dilemma of producing more cacao while ensuring its sustainability. Cacao monocrops and agroforestry systems (AFS) are two contrasting ways to produce cocoa, yet their impact on yields, contribution to farmer livelihood, cocoa quality remains understudied. Therefore, we reviewed existing literature comparing (1) monocrop cacao farming systems with (2) simple or (3) complex AFS. We found 19 comparisons of the cocoa yields in monocrops and simple AFS and 20 comparisons of monocrop and complex AFS. Three main research findings derive from this work. First, in about one third of cases, cacao trees yield more (or equally) in AFS than in monocrops. However, when considering only simple AFS, cacao trees yield more or equal to cacao monocrop in 52% of the cases. Second, cocoa AFS yields an average of 14% less than cacao monocrop. Yet, on average simple AFS yielded 2% less than cacao monocrops. Finally, there are too little elements to draw conclusions about the nexus between cocoa quality and cacao tree cultivation system.

     

Soil productivity,soil conservation and land evaluation

ICRAF's main contributions to research related to soils have been a symposium, Soils Research in Agroforestry; a review of soil productivity aspects of agroforestry; a further review of the potential of agroforestry for soil conservation, covering both erosion control and maintenance of fertility; the construction of a computerized model to predict soil changes under agroforestry systems; and a handbook of practical methods of agroforestry for soil and water conservation in dryland Africa. In research on land evaluation, an environmental data base has been established, leading to a capacity to obtain information, for environmental conditions similar to those of a given site or area, on publications, multipurpose trees, crops, existing agroforestry systems and current experimental work. Land evaluation for agroforestry cannot be achieved merely by synthesis of methods from agriculture and forestry, but will require more data on the performance of agroforestry land utilization types. Recognition of problems of environmental degradation has become an integral part of planning for agroforestry research. By means of a partial synthesis between land evaluation and diagnosis and design, a procedure of site selection for agroforestry research and development has been established.Principal Scientist, ICRAF     

Distribution of oxidizable organic C fractions in soils under cacao agroforestry systems in Southern Bahia,Brazil

Agroforestry systems can play a major role in the sequestration of carbon (C) because of their higher input of organic material to the soil. The importance of organic carbon to the physical, chemical, and biological aspects of soil quality is well recognized. However, total organic carbon measurements might not be sensitive indicators of changes in soil quality. Adoption of procedures that can extract the more labile fraction preferentially might be a more useful approach for the characterization of soil organic carbon resulting from different soils. This study aimed to evaluate organic carbon (C) fractions distribution in different soil layers up to 50 cm depth in two soil orders under cacao (Theobroma cacao) agroforestry systems (AFS) in Bahia, Brazil. Soil samples were collected from four depth classes (0–5, 5–10, 10–30 and 30–50 cm) under two cacao agroforestry systems (30-year-old stands of cacao with Erythrina glauca, as shade trees) in Latosol and Cambisol, in Bahia, Brazil. The determination of oxidizable carbon by a modified Walkley–Black method was done to obtain four C fractions with different labile forms of C (fraction 1: labile fraction; fraction 2: moderate labile fraction; fraction 3: low labile fraction and fraction 4: recalcitrant fraction). Overall, at two cacao AFS, the C fractions generally declined with increase in soil depth. The C fractions 1 and 2 were 50% higher on upper layers (0–5 and 5–10 cm). More than 50% of organic C was found in more labile fraction (fraction 1) in all depths for both soils. High value of C fraction 1 (more labile C)-to-total organic C ratio was obtained (around 54–59%, on Latosol and Cambisol, respectively), indicating large input of organic matter in these soils.     

Use of the iterative diagnosis and design approach in the development of suitable agroforestry systems for a target area

The process of iterative diagnosis and design with the active participation of farmers and extension agents was found effective in identifying appropriate agroforestry systems for farmers in the Bugesera and Gisaka-Migongo (BGM) regions of Rwanda. Periodic re-evaluation of research assumptions and technology designs was based on feedback from farmers and extentionists through regular visits to station trials, early initiation of on-farm testing, and interaction with farmer cooperators through informal discussions and formal surveys focused on specific agroforestry technologies. Statistical analysis is valuable for comparison between regions or periods. However, valid conclusions can be drawn without statistics, by employing several farmer-participatory approaches and pooling and properly interpreting the data obtained from them. Farmers' preferred uses of tree biomass in the BGM regions and appropriate agroforestry systems are discussed. If researchers and development agents do not consider the farmers' real needs, circumstances, available resources and management capacity with regard to tree planting, they will fail in identifying and extending suitable agroforestry systems for any region. This study was a part of the ISAR/IITA/World Bank FSR Project, implemented in the BGM regions of Rwanda during 1983–1988.