Agroforestry pathways for the intensification of shifting cultivation

As a system of land use which entails the deliberate association of trees with herbaceous field crops in time, shifting cultivation is one of the most ancient, widespread and, until recently, ecologically stable forms of agroforestry. However, under pressure of population and competing uses for land and labour, traditional swidden systems have been observed historically to undergo more or less predictable processes of intensification. Since shifting cultivation is an indigenous form of agroforestry, scientific agroforestry is not, strictly speaking, an alternative to shifting cultivation, but rather a systematic approach to the recombination of its basic elements into more intensive, sustainable and politically viable forms of land use, whenever pressures signal the need for change in traditional swidden systems.Different agroforestry options open up from different stages of intensification in swidden systems. A review of evolutionary typologies of shifting cultivation gives rise to a framework for the identification of agroforestry interventions and development pathways appropriate to specific systems. technological proposals are limited to a short list of the most promising agroforestry interventions in main sequence swidden systems. These include integral taungya, economically and biologically enriched fallows, variations on the alley cropping theme, and various tree crop alternatives to annual cropping systems. Examples and quantitative data are cited to substantiate the main hypotheses behind the proposals.     

Über den chemischen Pflanzenschutz und seine Perspektiven in der ČSSR

Chemical plant protection and its perspectives in SSR A number of 374 chemical preparations for plant protection are licenced in SSR. Yearly more than 5.5 millions ha of tilled land are treated with chemical pesticides. The parts of effective groups in the plant protection measures amount to: herbicides = 62%, fungicides = 16%, biological preparations = 12.7%, insecticides = 9.3%. Chemical control actions injure the structure of agrocoenoses, therefore integrated control measures must be introduced for the purpose of reducing the injuries as far as possible. Solely when the critical number of a pest species is overstepped chemical control should be applied. In SSR 8 species of animal pests are objects of prognosis; 23 animal species as well as a virus disease and 2 mycoses are objects of the warning service.     

Paraiso (Melia azedarach var. “Gigante”) woodlots: an agroforestry alternative for the small farmer in Paraguay

This paper describes the salient aspects and analyses the potential of the Paraiso Woodlot System, which is becoming popular as an agroforestry alternative to land use in the degraded acid sandy soils of the humid sub-tropical Guayaybi area of Paraguay. The system consists of a combination of paraiso (Melia azedarach var gigante) with other trees, especially Leucaena leucocephala, and annual crops.The fast growth habit, deep root system, addition of large quantities of organic matter through leaf and litter fall, compatibility with agricultural crops, high value of the sawlogs and production of substantial quantities of poles and firewood make paraiso an excellent species for agroforestry combination. Preliminary results of the trials indicate that the woodlots are successful and with increasing efforts of the extension agencies, they are being accepted as a viable alternative to traditional agricultural systems.Besides discussing the potential of these woodlots based on initial results, the paper identifies the constraints of the system and highlights the priority research areas.     

Mapping the territory: agroforestry awareness among Washington State land managers

There is growing interest in research to develop potential agroforestry models for temperate climates. In Washington State, recent studies and anecdotal information suggest that agroforestry is already employed by land managers, and if so, this experience should inform future research efforts. Because this population is not well defined, a mail survey was designed to: 1) Assess Washington land manager awareness of agroforestry, 2) assess perceptions of agroforestry as a land management tool, 3) assess the perceived potential opportunities or obstacles for land managers to practice agroforestry, and 4) identify landowner groups believed to be practicing agroforestry in Washington State.Three groups of land managers were surveyed: employees of the Soil Conservation Service (SCS), Washington State University Cooperative Extension Service (WSUCE) and OTHER, consisting of university faculty, private land managers, State and Federal land managers and owners of small natural resource businesses.Agroforestry was not a new concept for most (94%) respondents, further 55% of those familiar with agroforestry were practicing agroforestry or providing advice to landowners who were practicing agroforestry. Use in (government mandated) soil conservation plans on farmland (100% of all respondents) was the most frequently cited potential application for agroforestry in the state followed by range and pasture land and managing non-commercial forest land (both 84%), use on commercial forest plantation (83%) and fruit and nut orchards (61%).Diversifies land use (25%), enhanced productivity (18%), aesthetics (13%) and income diversity (13%) were the four most frequently cited potential advantages to practicing agroforestry. Lack of information (28%), lack of technical assistance (18%), establishment costs (14%) and not an established practice (14%) were the most frequently identified potential obstacles to practicing agroforestry. Respondents suggested there is great potential for application of agroforestry throughout the state, and non-industrial private forest land owners were selected for future study of this potential.     

The role of extension in agroforestry development: evidence from western Kenya

The extension strategy used by the CARE International in Kenya Agroforestry Extension Project (AEP) is described. This strategy is evaluated in terms of documented changes in farmer's agroforestry practices and the importance of AEP relative to other changes in economic incentives, institutional support, and land use and tenure rules for agroforestry. The project served mainly to increase awareness of the multipurpose potential of agroforestry, expand available technical options, and strengthen local institutions. Its community-based extension approach was more suitable for local conditions than commodity-based, training-and-visit, farming systems, or media-based extension. Projects are encouraged to tailor extension design to local circumstances, use community participation to guide extension priorities, and use extensionists as catalysts and information brokers.Research undertaken while the author was a Principal Scientist at the International Council for Research in Agroforestry, Nairobi, Kenya.     

Agroforestry and portfolio theory

Portfolio theory is used to analyse the risk of hypothetical agroforestry systems. It is shown that the relationship of the returns of the components of an agroforestry system, expressed in terms of the covariance or correlation of returns, is of vital importance in correctly defining risk. Agroforestry systems can be classified as efficient or inefficient. Inefficient systems are such that an alternative system exists which has a greater return for the same level of risk. Thus, inefficient systems do not represent rational choices for agroforestry systems. Finally, the conclusion is reached that it is impossible to design a best system, but rather a set of efficient systems of differing risk and return can be defined. This set of efficient systems is referred to as the efficient frontier.     

The tree/crop interface — or simplifying the biological/environmental study of mixed cropping agroforestry systems

A key to understanding the biological potentials and restraints of agroforestry systems, and the environmental responses of plant components within them, is the tree/crop interface. All agroforestry systems can be studied by separating the growth and yield characteristics of the three basic sets of variables (a) the sole agricultural crop (b) the effects of the tree/crop interface on the crop and tree and (c) the growth of the tree as a whole crop.The interface can be studied wherever it occurs in natural situations, or conventional or systematic experimental layouts, but very simple forms of geometric layouts can be very space efficient.

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Resumer La interfase arbol/cultivo, o como simplificar los estodios biologicoambientales de sistemas mixtos de cultivos agrogorestales.La interface arbol/cultivo es la clave para entender el potencial y las limitaciones biologicas de los sistemas agroforestales, y de la respuesta ambiental de las plantas dentro de los mismos. Todos los sistemas agroforestales pueden ser estudiados separando las caracteristicas de crecimiento y rendimiento de los tres conjuntos basicos de variables: (a) el cultivo agricola solo; (b) los efectos de la interfase arbol/cultivo sobre el cultivo y los arboles; y (c) la plantation forestal sola.La interfase puede ser estudiada cuando ella ocurre en situaciones naturales, o en arreglos experimentales convencionales o sistematicos, pero formas simples de arreglos geometricos pueden ser muy eficientes en el uso del espacio.

     

Agroforestry diagnostic survey of some parts of Niger State of Nigeria

A diagnostic survey of agroforestry practice carried out in seven Districts within Zone III of Niger State of Nigeria revealed that the agro-silvi-pastoral and the scattered farm trees systems were the most common agroforestry practices adopted by the farmers. About 99.5% of agroforestry trees planted by the farmers were fruit/vegetable-producing while the remaining 0.5% were meant for other purposes. Tree-planting appears to be more linked with farmers' awareness rather than age, family size and farm size. The farmers' earnings could be increased by intensified agroforestry practice, while the latter can be achieved by intensified agroforestry extension and provision of incentives.     

Amazonian agroforestry: a market-oriented system in Peru

Most reports on indigenous agroforestry systems of the Amazon region have described patterns employed by tribal groups almost exclusively for their own subsistence. This article discusses a market-oriented cyclic agroforestry system practiced by non-tribal Mestizo farmers in Tamshiyacu, Peru. The system produces charcoal, as well as annual, semi-perennial, and perennial crops for local consumption, and for a regional market. The sale of these products provides a substantial cash income for many farmers. The data presented demonstrate that Amazonian cyclic agroforestry systems are capable of being commercially successful enterprises and of serving as possible models for further agricultural development.

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Resumen La mayoria de informes sobre sistemas agroforestales indígenas de la regíon amazónica han descrito formas utilizadas por grupos nativos casi exclusivamente para su subsistencia. Este artículo trata de un sistema agroforestal cíclico comercial empleado por agricultores mestizos en Tamshiyacu, Perú. Este sistema produce carbón, huertos anuales, semi-perennes y perennes para el consumo local y para el mercado regional. La venta de estos productos da un ingreso considerable a muchos agricultores. Los datos presentados demuestran que sistemas agroforestales amazónicos pueden tener valor comercial y servir de modelos eventuales para el desarrollo agrícola.

     

Natürliche Feinde des Goldafters,Euproctis chrysorrhoea L., im Gebiet von Kosovo,FSR Jugoslawien

Summary Natural enemies of Euproctis chrysorrhoea in orchards in Yugoslavia During an outbreak ofEuproctis chrysorrhoea in orchards near Kosovo, Yugoslavia, several parasites (Larvaevoridae and Ichneumonidae especiallyApanteles), predators (Coleoptera of the generaCantharis andMalachius) as well as a protozoic disease were observed attacking the pest. The disease agent was recognized to be a new species:Nosema kovaevii sp. n. (Microsporidia). The cycle of development of the new species is described. Opposite to related species the spores ofN. kovaevii show a great variety in length.     

Estimated stocks of organic carbon in mangrove roots and sediments in Hinchinbrook Channel,Australia

Aboveground and belowground root biomasses (Babove and Broot) were measured for young, isolated Rhizophorastylosa on Iriomote Island, Japan. The relationship between these two parameters was significant and given as the equation, Broot(g dry weight) = 0.394 × Babove(g dry weight) – 485 (r = 0.986). Multiple regression analyses also revealed good correlation between diameter and biomass of prop roots (Dprop and Bprop) and between prop root and root biomasses. Consequently, root biomass could be estimated from the measurements of diameter and biomass of prop roots using the multiple regression equation, Broot(g dry weight) = 80.0 ×Dprop(cm) + 0.86 ×Bprop (g dry weight) – 251. The relationship between DBH (diameter at breast height) and prop root biomass was also adequately described using an allometric equation.In Hinchinbrook Channel, Australia, redox potential (measured as Eh) and organic carbon stocks in the top 5cm of mangrove sediments were measured along a 600m transect from the frequently inundated, Rhizophora dominated zone on the creek edge, towards higher grounds, where Ceriops spp. became increasingly dominant. Eh values were about –60mV near the creek edge and increased to 260mV on higher grounds. Organic carbon stocks showed an opposite trend to Eh, with the values decreasing from about 360tCha–1 to 160tCha–1. At 18 sites, representing six different habitats, organic carbon stocks were also measured along with the DBH of mangrove trees. DBH was converted into aboveground biomass and then into root biomass using the equations obtained in the study on Iriomote Island. The average organic carbon stocks in the top 50 cm of sediments, aboveground biomass and root biomass were 296tCha–1, 123 tCha–1 and 52 tCha–1, respectively, and accounted for 64%, 25% and 11% of the total organic carbon stock.     

FAO initiatives in agroforestry training in Latin America

In response to the request of its member countries from the Latin America and the Caribbean to help promote agroforestry, FAO has initiated a number of activities in the region. These include a regional project Demonstration and Training in Agroforestry in Latin America, an International Workshop on the Formulation of a Project on Demonstration and Training in Agroforestry for the Amazon, held in January 1993, and the project Participative Forestry Development in the Andes. Currently, FAO assistance to the countries of the region in their efforts to promote agroforestry include The Latin American Technical Cooperation Network on Agroforestry Systems, FAO's country-specific technical cooperation projects, and assistance in obtaining development-bank loans through missions of the FAO Investment Center.     

Scale effects in crop—fallow rotations

Many aspects of scaling up must be considered in the spectrum between promising results of new technologies in experimental plots and wide adoption by farmers. These aspects include extrapolating in time to optimize management decisions, extrapolating in space from small plots to large fields and to other farms and regions, and enlarging the range of (presumed) beneficiaries. Models can help in all these aspects to lay a biophysical foundation on which socioeconomic decisions can be built. We focus here on improved fallow systems where trees are planted to restore soil fertility for subsequent food crops. The restoration of soil fertility — based on biomass production, litterfall, and build-up of dynamic soil organic matter pools — depends on total resource capture by the fallow vegetation. Where lateral resource capture and lateral resource flow play a substantive role in the performance of the fallow, the size (scale) of fallow and cropped plots may influence both the build-up and the decline of soil fertility during a cycle. On small farms, fallow systems should not be seen as pure sequential systems, but as mosaics of spatially interacting fallow and cropped plots. Border effects depend on the lateral spread of the root system of the fallow vegetation, as well as on rainfall and N supply. Scale effects in technology adoption include both positive and negative feedback effects, because the spread of a technology may both accelerate innovations as well as increase threats from pest and disease attack.This revised version was published online in November 2005 with corrections to the Cover Date.     

Biomass and production of fine and coarse roots of trees under agrisilvicultural practices in north-east India

An understanding of the rooting pattern of tree species used in agroforestry systems is essential for the development and management of systems involving them. Seasonal variation, depth wise and lateral distribution of biomass in roots of different diameter classes and their annual production were studied using sequential core sampling. The investigations were carried out in four tree species under tree only and tree+crop situations at ICAR Research Farm, Barapani (Meghalya), India. The tree species were mandarin (Citrus reticulata), alder (Alnus nepalensis), cherry (Prunus cerasoides) and albizia (Paraserianthes falcataria). The contribution of fine roots to the total root biomass ranged from 87% in albizia to 77% in mandarin. The bulk of the fine roots (38% to 47%) in the four tree species was concentrated in the upper 10 cm soil layer, but the coarse roots were concentrated in 10–20 cm soil depth in alder (46%) and albizia (51%) and at 0–10 cm in cherry (41%) and mandarin (48%). In all the four tree species, biomass of both fine- and coarse-roots followed a unimodal growth curve by showing a gradual increase from spring (pre-rainy) season to autumn (post rainy) season. Biomass to necromass ratio varied between 2 to 3 in the four tree species. The maximum (3.2) ratio was observed during spring and the minimum (2) in the rainy season. In alder and albizia, the fine roots were distributed only up to 1 m distance from the tree trunk but in the other two species they were found at a distance up to 1.5 m from the tree trunk. The annual fine root production varied from 3.6 Mg ha^–1 to 6.2 Mg ha^–1 and total production from 4.2 to 8.4 Mg ha^–1 in albizia to mandarin, respectively. Cherry and mandarin had a large number of woody roots in the surface layers which pose physical hindrance during soil working and intercultural operations under agroforestry. But the high biomass of roots of these two species may be advantageous for sequential or spatially separated agroforestry systems. However, alder and albizia have the most desirable rooting characteristics for agroforestry systems.This revised version was published online in November 2005 with corrections to the Cover Date.     

From forest to agroforest and logger to agroforester: a case study

This paper examines interactive change and adaptation of human and natural systems in two pioneer forest settlements in the Philippines. The forest ecosystem was converted by logging, further resource extraction by settlers, and cultivation — factors usually associated with systems degradation. Natural succession, however, was rapid because of high rainfall and abundant forest seed stocks; and because of high rainfall, weeds, insect pests, and poor soil — annual cereal and cash cropping was not profitable or sustainable and farmers turned to root and mixed perennial cropping. This naturally developing, more sustainable agroforestry was initially financed by boom-and-bust incomes from small scale logging and charcoal making, and took place in spite of the settlers' formation of factions and an us before them attitude towards resource use.     

Planning optimal economic strategies for agroforestry systems

Design of agroforestry systems requires a land management planning process that clearly specifies wants, needs and objectives along with the land's suitability for potential agroforestry practices. Within this planning process economic analysis can be used to analyze agroforestry alternatives to help determine the proper system to apply. Specifically, production economics coupled with capital theory and valuation techniques can provide measures of economic performance in terms of present net values, benefit-cost ratios and internal rates of return. These economic performance measures can be used to determine the best joint production level for a particular agroforestry practice. Once these best combinations have been defined, linear programming can be applied using these best joint production combinations as decision variables along with considering a wide range of additional constraints and requirements. A hypothetical example is used to illustrate the planning process and how these economic tools can be combined as a package to help determine optimal agroforestry strategies.     

An outline of the research and education program of CIES/Consortium

The CIES/Consortium was created in 1992 for increasing the personnel capability and conducting research in natural resources, sustainable development, and human health in the Chiapas region of Mexico. Research is being conducted in four principal study areas: Highlands of Chiapas, the Lacandon rain forest, Soconusco, and El Ocote Reserve. There are four research departments: Conservation of Natural Resources, Alternative Production Systems, Health and Population, and Agroecological Technology. Agroforestry research, within the Department of Alternative Production Systems, includes agroforestry systems diagnosis in the highlands of Chiapas, ethnobotanical survey of potentially useful woody plants, silvicultural evaluation of woody forage species, management alternatives for the fallow vegetation in the Lacandon rain forest, and forest regeneration ecology and biomass dynamics in the Highlands of Chiapas and Lacandon rain forest after human interference. The CIES/Consortium researchers are also involved in the training of professionals and supervision of bachelor- and master- theses in their respective study areas. In January 1994, CIES/Consortium started a Postgraduate program in Natural Resources and Rural Development.Centro de Investigaciones Ecológicas del Sureste; since October 19, 1994 the name has changed to El Colegio de la Frontera Sur (ECOSUR).     

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.     

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 system of classification of woody perennials based on their root activity patterns

A method of classifying woody perennials based on the effective foraging space (EFS) is described. EFS of a plant is defined as the soil space which accounts for 80% or more of root activity. The lateral and vertical dimensions of EFS of a plant can be determined from the study of root activity pattern of the plant employing ³²P-soil injection technique. Based on the dimensions of the EFS, the perennial plant species may be grouped into 16 classes ranging from plants with very compact-very shallow active root system (less than 100 cm lateral extension and less than 30 cm deep) to very extensive — very deep root system (more than 300 cm lateral spread and more than 90 cm deep). The soil and genetic factors which can influence root activity pattern of a plant can also alter its EFS. Nevertheless, given the soil type and the variety, the concept of EFS can be very fruitfully applied in several situations such as selection of plant species for a given land use system, spacing of the component species in agroforestry and other mixed production systems, deciding the planting geometry, developing the most efficient method of fertilizer application, choosing the most appropriate crop combinations for stratified exploitation of below-ground resources, etc. Although this classification system is primarily intended for woody perennials, it can be extended to other plant species as well.This revised version was published online in November 2005 with corrections to the Cover Date.