Economics of the plant species used in homestead agroforestry on an offshore Sandwip Island of Chittagong District, Bangladesh

Introduction Bangladesh is a land hunger country having about 14.4 million hectares of land with a population of 133 million (BBS 2003). Of the total land area, about 1.48 ×106 hm2 are designated as government forest land, 0.72 million hectares are of Un…     

Alternate cycle agroforestry

Agroforestry research and design has heavily favored intergrated production of annuals and perennials, that is production of tree crops on the same parcel of land and at the same time as production of food crop annuals. For areas having high population densities and intensive modes of agricultural production, integral agroforestry may be appropriate, but for areas of sparse population where extensive agriculture is practiced or marginal hill lands, alternate cycle agroforestry may prove more suitable. Alternate cycle agroforestry, in the form of modified forest swidden systems, is discussed and compared to integral agroforestry systems. Advantages and disadvantages of each system are discussed relative to their use on marginal hill and forest lands.The author wishes to thank N.T. Vergara, L.S. Hamilton, A.T. Rambo and K.F.Wiersum at the Environment and Policy Institute of the East-West Center for their comments.     

浅谈农林复合研究

对目前国内的农林复合研究现状进行概述,提出农林复合研究中存在的一些问题,并对未来的研究方向提出几点建议。     

Indigenous agroforestry of Pohnpei

Plant species and cultivars of the indigenous agroforestry system of Pohnpei were surveyed in transects through 54 randomly-selected farms. The agroforestry system was characterized by extensive cultivation of yams (Dioscorea), aroids (Alocasia), and Piper methysticum under a permanent overstory of breadfruit, coconut, and forest remnant trees and a middle canopy of Hibiscus tiliaceus, Musa spp., and Morinda citrifolia. In the 10 ha of survey plots, 161 species were found, of which 102 were trees, shrubs, and crops and 59 were uncultivated herbaceous plants. Numbers of tree, shrub, and crop species per farm ranged from 16 to 37 with an average of 26. Twenty-eight breadfruit and 38 yam cultivars were found in the survey plots, showing that cultivar diversity is an important component of the biological diversity maintained and utilized in Pohnpeian agroforests.     

Classification of agroforestry systems

Classification of agroforestry (AF) systems is necessary in order to provide a framework for evaluating systems and developing action plans for their improvement. The AF Systems Inventory (AFSI) being undertaken by ICRAF provides the background information for an approach to classification.The words system, sub-system and practice are commonly used in AF literature. An AF system refers to a type of AF land-use that extends over a locality to the extent of forming a land utilization type of the locality. Sub-system and practice are lower-order terms in the hierarchy with lesser magnitudes of role, content and complexity. In common parlance, however, these terms are used loosely, and almost synonymously.Several criteria can be used to classify and group AF systems (and practices). The most commonly used ones are the system's structure (composition and arrangement of components), its function, its socio-economic scale and level of management, and its ecological spread. Structurally, the system can be grouped as agrisilviculture (crops — including tree/shrub crops — and trees). silvopastoral (pasture/animals + trees), and agrosilvopastoral (crops + pasture/animals + trees). Other specialized AF systems such as apiculture with trees, aquaculture in mangrove areas, multipurpose tree lots, and so on, can also be specified. Arrangement of components can be in time (temporal) or space (spatial) and several terms are used to denote the various arrangements. Functional basis refers to the main output and role of components, especially the woody ones. These can be productive functions (production of basic needs such as food, fodder, fuelwood, other products, etc.) and protective roles (soilconservation, soil fertility improvement, protection offered by windbreaks and shelterbelts, and so on). On an ecological basis, systems can be grouped for any defined agro-ecological zone such as lowland humid tropics, arid and semi-arid tropics, tropical highlands, and so on. The socio-economic scale of production and level of management of the system can be used as the criteria to designate systems as commercial, intermediate, or subsistence. Each of these criteria has merits and applicability in specific situations, but they have limitations too so that no single classification scheme can be accepted as universally applicable. Classification will depend upon the purpose for which it is intended.Nevertheless since there are only three basic sets of components that are managed by man in all AF Systems, viz. woody perennials, herbaceous plants and animals, a logical first step is to classify AF systems based on their component composition, into agrisilvicultural, silvopastoral and agrosilvopastoral (or any other specialized) systems. Subsequently the systems can be grouped according to any of the purpose-oriented criteria. The resulting system name can thus have any one of the three basic categories as a prefix; for example agrisilvicultural system for soil conservation.Some of the major AF systems and practices of the tropics are grouped according to such a framework. The scheme appears a logical, simple, pragmatic and purpose-oriented approach to classification of AF systems.     

Economic aspects of agroforestry

Agroforestry is analysed by means of economic concepts. The paper is mainly theoretical, since there are little adequate data to test the conceptual framework.Agroforestry needs not be limited to integration of agriculture and forestry on a plot, but may also include integration on a holding. Design and evaluation of agroforestry systems require thorough knowledge of relationships between agriculture and forestry. Complementary and supplementary relationships, mainly resulting from biological factors, were identified, which make agroforestry an efficient system of land use.Agroforestry can be an appropriate technology in areas with fragile ecosystems and subsistence farming. The objectives of participants in an agroforestry programme may not coincide with social objectives, and so do not lead to the socially optimum combination of agriculture and forestry. For that social optimum institutional arrangements will often be required.This paper is s shortened updated version of part of a lecture series on agroforestry, organized by the Departments of Forestry, Agricultural University, Wageningen [29].The author thanks his colleagues C.P. Veer and K.F. Wiersum for helpful comments.     

Fertilizers in agroforestry systems

This review encompasses results of fertilization experiments on several agroforestry systems—alley cropping, perennial shade systems, home gardens—in which fertilizer use is a likely management alternative. Fertilizer response was found to be most common in alley cropping, variable in perennial shade systems, and rarely reported in home gardens. Level of nutrient removal in harvested products is probably the overriding factor in determining fertilizer response; greater accumulation of organic residues, slower growth under shade, and longer periods of nutrient uptake probably also contribute to the relatively smaller fertilizer response of the perennial shade systems and home gardens. Considerable knowledge gaps exist regarding the breakdown of organic residues, and interactions between mineral and organic amendments. Systems based on annual crops (e.g., alley cropping) are likely to be less nutrient-efficient and sustainable than systems based on perennial crops, due to reduced fixation and transfer of N to the crops, the tendency of the trees to compete for and sequester nutrients, relatively high P requirements of the crops, and the high labor cost of tree management. The possible benefits of fertilization of specific components in home gardens, and relative advantages of including low-value tree legumes, high-value shade trees, and fertilization in shaded perennial systems are only beginning to receive research attention.     

Homestead agroforestry in Bangladesh

The Homestead agroforestry system is very important in the economy of Bangladesh. The many woody species grown in the homesteads are a significant source of fuelwood; they also provide fodder, building materials and other forms of wood. In the context of the prevailing shortage of fuelwood and excessive deforestation in Bangladesh, this homestead agroforestry system needs to be strengthened. A field survey was undertaken to assess the prospects and feasibility of initiating a programme for the improvement of homestead agroforestry systems. It showed that the prospects for improving homestead agroforestry systems are good because most respondents own their homesteads and believe there is room for more trees on them. Although they know that raising trees is relatively difficult and requires special practices, they are familiar with the government nurseries and local agricultural extension officers, and are confident about the success of the programme. Results also indicate that multipurpose trees and specific modules for involving women in the farm operations are likely to enhance success of the programme.     

Planning methods for agroforestry

One of the major issues facing the world is the interrelated problem of deforestation and concurrent degradation of agricultural lands in tropical and subtropical nations. Agroforestry is one technique to help alleviate this problem. Implementation of newly developed agroforestry techniques in various places all over the world, has made it clear that:

Problem solving cannot be limited to the individual farmstead or plot level from a social and ecological point of view.

Existing landscapes present both constraints and opportunities for further land development.

More appropriate agroforestry techniques can be applied by classifying landscape units and existing land-use systems.

Planning is necessary because agroforestry requires a holistic perspective to be sustained during the long time necessary for implementation.

For these reasons, a review of planning methods used in agroforestry and suggestions for their improvement seems timely. Selected existing methods, with an emphasis on those being used in Kenya, are analyzed in terms of goals, community needs, site assesment, options for action, implementation, management, and evaluation. Our review was conducted through literature survey and interviews with key informants in Nairobi, Kenya; Wageningen, the Netherlands; and Washington, D.C., U.S.A. Landscape planning might be an approach that can be used with agroforestry to provide a more comprehensive perspective. The role of landscape planning in agroforestry projects is discussed in detail, using a study from Kenya for illustration.     

Poplar agroforestry in India

The development of poplar agroforestry and associated research in India is reviewed. The model of agroforestry development involving a partnership between farmers, the private sector and the government is worthy of further investigation for application in other areas of India and to other countries. A number of suggestions are given for further research in the context of optimising the system for resource-poor farmers. These include changes in tree and crop varieties, tree spacing, and utilisation of small diameter logs, and other poplar products.     

A general classification of agroforestry practice

Present classification schemes confuse agroforestry practices, where trees are intimately associated with agricultural components at a field scale, with the whole farm and forest systems of which they form a part. In fact, it is common for farming systems to involve the integration of several reasonably discrete agroforestry practices, on different types of land. The purpose of a general classification is to identify different types of agroforestry and to group those that are similar, thereby facilitating communication and the organized storage of information. A new scheme is proposed that uses the ‘practice’ rather than the ‘system’ as the unit of classification. This allows an efficient grouping of practices that have a similar underlying ecology and prospects for management. A two stage definition of agroforestry is proposed that distinguishes an interdisciplinary approach to land use from a set of integrated land use practices. Four levels of organization are recognized through analysis of the role of trees in agricultural landscapes: the land use system, categories of land use within systems, discrete groups of components (trees, crops, animals) managed together, and functionally connected groups of such discrete practices in time and space. Precedents for this form of analysis are found in the literature and it conforms with generally accepted methods of systems analysis. Classification of major types of agroforestry practice proceeds primarily according to the components involved and the predominant usage of land. A secondary scheme further classifies these in terms of the arrangement, density and diversity of the tree components involved. This revised version was published online in June 2006 with corrections to the Cover Date.     

Data recording for agroforestry experiments

Examples of typical data-sets from agroforestry trials are considered and difficulties with the recording of such data are discussed. Suggestions for efficient data recording for a number of agroforestry trials are made so that easy data-checking, efficient computer entry and accurate analysis can be produced without the need for excessive data manipulation at each stage. General recommendations for data-recording from agroforestry trials are given.     

Promising agroforestry systems in Venezuela

The main agroforestry systems in Venezuela are the multispecies plant associations in integrated coffee production system and the silvopastoral system. This paper describes the functional and structural aspects of these systems. The multilayered coffee production systems are practised mainly in the premontane moist forest of the Andes region, but are also found in other areas of the country. Various tree species are used for shade and as fence in big coffee plantations, whereas in small units with traditional production pattern, coffee is planted along with many other species, often constituting a 3–4 layer canopy. Available data are presented on the production as well as some socioeconomic aspects.The silvopastoral systems are found in the tropical dry forest (savannas) and in the very dry tropical forest of the semiarid zones of the country. A large number of trees and shrubs are found in these pastoral areas where they play both productive (fodder and feed) and service (shelter) roles.Although both these systems are practised over large areas of the country, practically no research has been done to improve them. In order to strengthen national capability to undertake such research, international support of cash and as well as technical advice is needed.

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Resumen Los principales sistemas agroforestales en Venezuela son el Sistema integrado de producción de café y el sistema silvopastoril. En el presente trabajo se describen aspectos funcionales y estructurales de esos sistemas. El sistema de producción multi-estratificado de café es practicado principalmente en el bosque húmedo premontano de la región andina, per también es frecuentemente observado en áreas del país. Diferentes especies de árboles son utilizados como sombra y como cercos vivos en las grandes plantaciones de café, mientras que en las pequenas unidades con un patrón de producción tradicional, el café es plantado junto con una gran diversidad de especies constituyendo un dosel vegetativo de 3–4 estratos.Información disponible sobre producción y algunos aspectos socio-económicos es presentada en el trabajo.Los sistemas silvopastoriles son encontrados en el bosque seco tropical (sabanas o llanos) y en el bosque muy seco tropical de las zonas semiaridas del país. Un gran número de árboles y arbustos se encuentran en esas áreas de pastoreo donde juegan un doble rol, producción (forraje ya alimento) y servicio (refugio y abrigo).Aunque ambos sistemas son practicados en grandes áreas del país, practicamente ninguna investigación se ha llevado a cabo para mejoralos. Con el objeto de fortalecer la capacidad en el país de llevar a cabo tal tipo de investigación, se hace necessario recursos economicós y asesaría técnica por parte de organizaciones internacionales.

     

Status of agroforestry education in India

India is perhaps the world leader in development of agroforestry education, training and research. The Indian Council of Agricultural Research sanctioned an All-India Coordinated Research Project on agroforestry in 1983, to be headquartered in Delhi but with research centers in 20 other locations countrywide. The agricultural universities in India have a major role to play, with all institutions having agroforestry teaching programs by 1990. At this point there is a great shortage of faculty trained in agroforestry. Demand for qualified graduates with this training is only going to increase.     

Traditional agroforestry practices in Zimbabwe

Traditional agroforestry systems in the communal areas of Zimbabwe are described. There are systems centered on main fields, on home gardens, on homesites and on grazing areas. In the main fields, the major tree-related management practice is the conservation of preferred indigenous fruit trees. Fruit trees are also the focus of forestry activities around the gardens and the homesite; but here it is the planting of exotic species. In a localized area of Zimbabwe Acacia albida is important in fields. There is almost no use of tree fallows in Zimbabwe. Trees in grazing areas have numerous roles, but at present there is little knowledge about traditional management practices in these areas. In the development of agroforestry systems in Zimbabwe it is suggested that those systems designed to improve fodder production will make a significant contribution to farm productivity because of the importance of cattle in the farming system and the present fodder shortage. Interventions involving the planting of fruit trees are likely to be very successful, as there is much interest in such planting. Another area that needs to be developed is that of tree plantings to improve soil fertility.     

Tree domestication in tropical agroforestry

Agroforestry Systems - We execute tree ‘domestication’ as a farmer-driven and market-led process, which matches the intraspecific diversity of locally important trees to the needs of...     

Carbon storage benefits of agroforestry systems

The process of land degradation is a local phenomenon that occurs field by field. Because of the extent at which it is occurring, however, it also has a global dimension. Agroforestry represents a link between the local and global scales. From the farmer's perspective, agroforestry can be a way to increase crop yields and the diversity of products grown. An additional benefit is the creation of a carbon sink that removes carbon dioxide from the atmosphere. Successful agroforestry systems will also reduce land clearing and maintain carbon in existing vegetation. An extensive literature survey was conducted to evaluate the carbon dynamics of agroforestry practices and to assess their potential to store carbon. Data on tree growth and wood production were converted to estimates of carbon storage. Surveyed literature showed that median carbon storage by agroforestry practices was 9 tC/ha in semi-arid, 21 tC/ha in sub-humid, 50 tC/ha in humid, and 63 tC/ha in temperate ecozones. The limited survey information available substantiated the concept that implementing agroforestry practices can help reduce deforestation.The research described in this article has been funded by the US Environmental Protection Agency. This document has been prepared at the EPA Environmental Research Laboratory in Corvallis, Oregon, through contract number 68-C8-0006 to ManTech Environmental Technology, Inc. It has been subjected to the Agency's peer and administrative review and approved for publication. Mention of trade names or commercial products does not constitute endorsement or recommendation for use.