Program design for agroforestry extension in the south-eastern USA

Before prioritising regional agroforestry training and extension content, it is necessary to discover which practices are common, what benefits are perceived, which barriers prevent use, and how people feel about practices. Agroforestry taps both agriculture and forestry agencies to increase the possible set of educators for landowners and managers. Interdisciplinary activities also present barriers to professionals unfamiliar with some topics or not served by lead partner agencies. To understand motives, barriers and needs involved in agroforestry extension and training activities for professionals, the Center for Subtropical Agroforestry (CSTAF) designed a survey to gauge knowledge, practice and information needs of professionals in Alabama, Florida and Georgia. Landowners in Alabama and Florida received similar survey questionnaires. Initial interviews of a test group with open-ended questions formed the basis for a closed-ended mail survey to all agriculture and natural resource extension agents and county foresters in the subtropical area. Response rates for various professional groups varied between 14% and 43%, and most ranked the potential for use of agroforestry as moderate or high. In all three states, wildlife habitat, water quality and soil conservation were the most important benefits seen by extension professionals. The most important concerns identified were lack of familiarity, lack of demonstrations, no financial incentive, and lack of information about agroforestry. These data provide insights about how to prioritise research and materials development and indicate that agroforestry training can be expected to be of value to at least half of the regional forestry and extension professionals.     

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.     

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.     

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.     

The agroforestry potential of combined production systems in north-eastern Mexico

In the semi-arid to sub-humid north-east of Mexico, no definite agroforestry practices were in use before the Spanish conquest, but present systems and practices offer a good basis for conversion to ecologically sustainable and productive multicrop systems which incorporate trees. In the mountains and on the coastal plain of the Gulf of Mexico, sub-humid tropical tree crops are found in mixture with semi-arid, mediterranean and even temperate species. Irrigation systems are energy and labour intensive and can be improved. Of special interest for farmers without access to finance, are non-irrigated systems mostly derived from the low dry forest (matorral), which yield crops, fruit and wood for different purposes and also serve for depasturing cattle. These latter practices have high potential for development and optimization.Integrated Expert, Agroforestry, CIM, Germany F.R., GTZ Project No. 81.9008.4     

Biophysical interactions in tropical agroforestry systems

The rate and extent to which biophysical resources are captured and utilized by the components of an agroforestry system are determined by the nature and intensity of interactions between the components. The net effect of these interactions is often determined by the influence of the tree component on the other component(s) and/or on the overall system, and is expressed in terms of such quantifiable responses as soil fertility changes, microclimate modification, resource (water, nutrients, and light) availability and utilization, pest and disease incidence, and allelopathy. The paper reviews such manifestations of biophysical interactions in major simultaneous (e.g., hedgerow intercropping and trees on croplands) and sequential (e.g., planted tree fallows) agroforestry systems. In hedgerow intercropping (HI), the hedge/crop interactions are dominated by soil fertility improvement and competition for growth resources. Higher crop yields in HI than in sole cropping are noted mostly in inherently fertile soils in humid and subhumid tropics, and are caused by large fertility improvement relative to the effects of competition. But, yield increases are rare in semiarid tropics and infertile acid soils because fertility improvement does not offset the large competitive effect of hedgerows with crops for water and/or nutrients. Whereas improved soil fertility and microclimate positively influence crop yields underneath the canopies of scattered trees in semiarid climates, intense shading caused by large, evergreen trees negatively affects the yields. Trees in boundary plantings compete with crops for above- and belowground resources, with belowground competition of trees often extending beyond their crown areas. The major biophysical interactions in improved planted fallows are improvement of soil nitrogen status and reduction of weeds in the fallow phase, and increased crop yields in the subsequent cropping phase. In such systems, the negative effects of competition and micro-climate modification are avoided in the absence of direct tree–crop interactions. Future research on biophysical interactions should concentrate on (1) exploiting the diversity that exists within and between species of trees, (2) determining interactions between systems at different spatial (farm and landscape) and temporal scales, (3) improving understanding of belowground interactions, (4) assessing the environmental implications of agroforestry, particularly in the humid tropics, and (5) devising management schedules for agroforestry components in order to maximize benefits. This revised version was published online in June 2006 with corrections to the Cover Date.     

Farmer perspectives on agroforestry opportunities and constraints in cape verde

In the água de Gato Watershed on the island of Santiago, Cape Verde Islands, 51 farmers were surveyed regarding their attitudes and knowledge of agroforestry. The farmers identified eight constraints to agroforestry implementation, with virtually all indicating that a source of loan funds was the major concern. Space or land constraints and availability of tree seedlings were identified as constraints by 94% and 88%, respectively. Despite these concerns, 92% of the farmers expressed a willingness to adopt or improve agroforestry practices in the watershed, with 73% expressing a willingness to establish fruit trees, 53% willing to establish trees or shrubs for fuelwood, and 16% willing to plant trees for shade.     

The role of agroforestry in the farming systems in Rwanda with special reference to the Bugesera-Gisaka-Migongo (BGM) region

The Rwandan farmers, faced with a perpetual land shortage, have evolved certain intensive systems of organic agriculture. These systems, particularly the homestead (compound) farming, involve the combination of food, fodder and tree crops. to a certain extent these systems can satisfy the multiple needs of the subsistence farmers living under several risks and constraints. However, they cannot cope with the expanding food demand of the rapidly increasing population. Some multipurpose, low-input technologies and agroforestry approaches have been designed to improve the productivity of these traditional systems; these include inter/mixed cropping systems and rotations, alley cropping with leguminous trees and shrubs, use of planted fallow, planting tree legumes on anti-erosive lines, mixed farming,community forestry and woodlots, and tree planting on farm/field boundaries. The essential aspects of these technologies are briefly discussed.ISAR-IITA FSR PROJECT, B.P. 629, Kigali RwandaISAR-Swiss Intercooperation, c/o Forestry Department, B.P. 617, Butare, Rwanda     

A knowledge-based expert system for planning and design of agroforestry systems

Computer-based Expert Systems that use knowledge, facts, and reasoning techniques to solve problems, normally requiring the abilities of human experts, are increasingly being used in many activities. The United Nations University (UNU) Agroforestry Expert System (AES) is a first attempt to apply this technique to agroforestry. UNU-AES is a prototype Knowledge-Based Expert System (KBES) designed to support land-use (agricultural, forestry, etc.) officials, research scientists, farmers, and individuals interested in maximizing benefits gained from applying agroforestry management techniques in developing countries. This prototype addresses the options for alley cropping, a promising agroforestry technology which has potential applicability when used under defined conditions in the tropics and subtropics. Alley cropping involves the planting of crops in alleys or interspaces between repeatedly pruned hedgerows of fast-growing, preferably leguminous, woody perennials. The primary benefits from this technique include nutrient enrichment, soil improvement, and erosion control. UNU-AES, which is the first known attempt at the application of expert system procedures in the field of agroforestry, uses a total of 235 decision rules to develop its recommendations. With the inclusion of more climatic and socio-economic data and improved advisory recommendations, UNU-AES can be expanded to provide advice on alley cropping in more diverse geographical and ecological conditions and eventually address other agroforestry techniques.     

A mathematical model for generating land-use allocation alternatives for agroforestry systems

Agroforestry has been considered a viable land-use system particularly in the tropical regions. In developing or designing agroforestry systems, various concerns have to be addressed namely: (1) economic; (2) biological and physical; and (3) silvicultural and ecological considerations. This paper addresses these concerns from an interdisciplinary perspective. A land-use allocation model which ensures the simultaneous consideration of these concerns is proposed.     

Farming system research and the quest for a sustainable agriculture

This paper brings together information from four sites in sub-Saharan Africa where FSR&D projects are located (Mali, Benin, Zambia and Tanzania), supported by the Royal Tropical Institute of The Netherlands. Common environmental constraints to agricultural productivity are analyzed, with an emphasis on aspects of soil fertility maintenance. It is shown that when plant nutrients are valued against market prices, annual crop production systems are inefficient due to considerable losses of nutrient resources (e.g., soil erosion) and economically unviable because of unfavourable input and producer price ratios. Technically solutions are available that make agriculture sustainable, but its output is likely to be reduced when accepting the need for environmental protection at various levels of integration (cropping system, field/farm, village territory, etc), since marginal land must be left under natural vegetation, and various forms of buffering elements must be installed on farms. The costs of protective measures (space, labour, energy in community organization) cannot be raised based upon local resources currently available. Making small farmer agriculture in the tropics sustainable and environmentally sound begins by improving economic conditions for farmers, raising producer income and lowering prices for inputs.     

Temporal analysis of agroforestry systems for rural development

Temporal analysis is introduced as a method to assess the suitability of agroforestry projects for meeting rural development objectives. This form of analysis provides a common base for examining social, economic, ecological, and managerial aspects of agroforestry systems.Temporal analysis begins by describing projects and the activities comprising them for both an agroforestry system and the local population. Factors constraining the sequence of activities are then examined. The assumptions and values regarding the past, present, or future are also analyzed for all groups involved in the agroforestry system. The range of goal oriented behavior affecting scale and duration of projects may be dependent on this time horizon.By understanding these factors, the changes in activities of a social system that may result from a proposed agroforstry innovation can be anticipated. The nature of these changes and their perception by the local population can be evaluated.     

Perennial crop-based agroforestry systems in Northeast Brazil

Land use systems in the Northeast Region of Brazil are dominated by large holdings and extensive cultivation of perennial crops such as cashew, coconut, carnauba wax palm, babaçu palm and so on. The common feature which links these crops is the silvopastoral system of livestock (chiefly cattle, sheep and donkeys) grazing under them. Agrosilvicultural systems involving cultivation of annual subsistence crops, and in some instances other perennials, in the stands of these perennial crops is also common. The paper presents the available information on the management, production, rate of growth, economic importance, etc. of these agroforestry systems involving cashew, coconut and carnauba palm. These systems are of considerable merit in the environmental, agricultural and socio-economic conditions of Northeast Brazil. However, practically no research nor even systematic data collection has been done on these so that there is an almost total lack of information on them. In order to improve the systems, they should be studied in detail and research undertaken on various components (crops, trees and livestock) individually as well as the system as a whole. Selection of suitable species of grass and other herbaceous crops, appropriate management techniques for both overstorey and understorey species in relation to the age of the overstorey species, optimal stocking rates of animals, etc. have to be determined so as to enable plantation owners and operators to realize the full potential of these systems.     

Modelling of rainfall interception loss in agroforestry systems

Two models of interception loss have been tested against new field data obtained in widely-spaced stands of Sitka spruce trees. The Gash model and a modified version of the Rutter model, have been used with data from an automatic weather station, to predict interception loss using parameters obtained from observations made in 1988 and 1989. The predictions for an eight-week period during 1987 were compared with measurements of interception loss. Good agreement between observed and predicted interception loss was obtained with both models over the whole period. The modified Rutter model gave better predictions than the Gash model for individual storm events and performed better at the wider spacings. The sensitivity of both models to the major characteristics of the tree stand structure in agroforestry systems was also investigated and it was shown that interception loss was most sensitive to boundary layer conductance and free throughfall coefficient.     

Sericulture-based agroforestry systems for hilly areas of north-east India

Sericulture-based agroforestry systems (AFS) have great potential for higher returns in the north-eastern region with sloping and valley-land conditions. A field investigation was initiated in November, 1992 at Research Farm, Barapani (980 m above msl, 26°N and 92°E and average rainfall 2428 mm/year) on acid Alfisol. Seven mulberry (Morus alba L.) varieties, seven silkworm breeds and rearing performance of a bivoltine breed, NB-18 were evaluated in different trials. Three sericulture-based AFS viz. sericulture with 1. fruit trees and fodder grasses, 2. field (upland) crops, and 3. lowland rice were developed at the Research Farm. Mulberry varieties TR-4, S-1635 and TR-10, and NB-18 — a bivoltine silkworm breed were found better suited for this region. Sericulture with field crops (French bean-groundnut-mustard/vegetables) for valley land, with fruit plants (guava, pineapple) and grasses for mid-hill situations, and with rice for low lands were found suitable at the Farm and for possible adoption in the north-eastern hill region of India.     

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.     

Insect pest problems in tropical agroforestry systems: Contributory factors and strategies for management

Agroforestry trees are attacked by a wide spectrum of insects at all stages of their growth just like other annual and perennial crops. Pest management in agroforestry has not received much attention so far, but recent emphasis on producing high value tree products in agroforestry and using improved germplasm in traditional systems, and emergence of serious pest problems in some promising agroforestry systems have increased awareness on risks posed by pests. Insects may attack one or more species within a system and across systems in the landscape, so pest management strategies should depend on the nature of the insect and magnitude of its damage. Although greater plant diversity in agroforestry is expected to increase beneficial arthropods, diversity by itself may not reduce pests. Introduction of tree germplasm from a narrow genetic base and intensive use of trees may lead to pest outbreaks. In simultaneous agroforestry systems, a number of factors governing tree—crop—environment interactions, such as diversity of plant species, host range of the pests, microclimate, spatial arrangement and tree management modify pest infestations by affecting populations of both herbivores and natural enemies. Trees also affect pest infestations by acting as barriers to movement of insects, masking the odours emitted by other components of the system and sheltering herbivores and natural enemies. In sequential agroforestry systems, it is mostly the soil-borne and diapausing insects that cause and perpetuate damage to the common hosts in tree—crop rotations over seasons or years. An integrated approach combining host-plant resistance to pests, exploiting alternative tree species, measures that prevent pest build up but favour natural enemies and biological control is suggested for managing pests in agroforestry. Species substitution to avoid pests is feasible only if trees are grown for ecological services such as soil conservation and low value products such as fuelwood, but not for trees yielding specific and high value products. For exploiting biological control as a potent, low cost and environmentally safe tool for pest management in agroforestry, research should focus on understanding the influence of ecological and management factors on the dynamics of insect pest-natural enemy populations. Scientists and policy makers in national and international institutions, and donors are urged to pay more attention to pest problems in agroforestry to harness the potential benefits of agroforestry.This revised version was published online in November 2005 with corrections to the Cover Date.     

The homegarden agroforestry system of Bukoba district,North-Western Tanzania. 1. Farming system analysis

Bukoba district is located in the north-western part of Tanzania and its economy is predominantly agricultural. Banana and coffee are, respectively, the most important food and cash crops. Population density is very high (500–1250 persons per km² of cultivated land) and so is the pressure on land and other natural resources. Farm holdings (homegardens) are mostly smaller than a hectare and continue to fragment as population continues to grow. A homegarden is locally known as Kibanja and it is both a social and economic unit of farm families in the district. Various crops, trees, shrubs, herbs and livestock are managed on the same piece of land mainly by family labour to provide food, cash, medicine, shade, poles, timber and some socio-cultural functions. This paper describes the homegarden agroforestry farming system of Bukoba, evaluates its viability and identifies critical constraints as well as research needs.     

On-farm agroforestry research in extension programmes: methods used by BAIF in India

The BAIF Development Research Foundation initiated an agroforestry extension project in Pune District, India in 1984, following earlier on-station research on leuceana-based alley-cropping systems for fodder. In extension meetings, farmers expressed a strong preference for planting a wide range of multipurpose trees on farm bunds and borders rather than single-species alley-cropping. Researcher-managed trials of proposed multipurpose species grown with crops were initiated, but were of limited value. An alternative approach to research was begun in 1988. This approach included a survey of agroforestry practices established by farmers through extension, and collection of data on crop yields by distance from the tree line from a sample of these plots. Research methods are described and modifications suggested for improving the quality of this type of extension-based research.     

Farmer-augmented designs for participatory agroforestry research

Two factors suggest that experimental designs used in on-station research are not appropriate for on-farm agroforestry research. First, successful technology development and validation requires farmer participation, which in turn requires more flexible experimental designs for on-farm experimentation. Second, the advent of widely available statistical computer packages and computing power allows the experimenter to deviate from ‘standard’ design restrictions of complete blocks and full replication. Farmer involvement in the research process should include the opportunity for farmers to ask questions and to define treatments along-side those of the researcher. To make inferences about farmer-defined augmented treatments that may only appear on one farm requires estimates of farm-by-treatment effects. This estimate can be obtained from the associated researcher's treatments that are applied to all of the farms participating in the trial. The use of augmented designs minimises plot number, while still enabling the researcher's and farmer's questions to be answered. The proposed design fills a methodological gap between informal farmer observation trials (where no statistical analysis is attempted) and larger scale extension trials (composed of simple treatment comparisons tested over a large number of farms).