Proceedings
Permanent URI for this communityhttp://hdl.handle.net/0/23
Browse
Browsing Proceedings by Subject "Agroforestry"
Now showing 1 - 8 of 8
- Results Per Page
- Sort Options
Item Agroforestry Research Experiences and Selected Highlights within the Agroforestry Research Network for Africa - East Africa Network(1996) Krah, K. A. ; Cooper, P.J.M.; Cooper and K. Atta Krah, International Centre for Research in AgroforestryThe paper begins by providing a context within which the Agroforestry Research Network for Africa - East and Central Africa has been functioning since 1989 It then proceeds to explain the structure and force on the organization in terms of current and future research activities These include research on soil fertility, terrace management and erosion control, wood and fodder production Research highlights selected from each of the participating countries are presented with respect to each theme. The paper concludes that when taken in total results reported contribute to a general understanding of the reasons why farmers plant trees and prefer particular species. Understanding these reasons is important for planning new interventions that meet farmers' needs and fit their particular circumstances.Item Agroforestry Research in the Miombo Ecozone: Experiences of the Southern Africa(1996) Ngugi, D.N.; Kwesiga, R.F.The Southern Africa AFRENA embraces four SADC countries, namely Malawi, Tanzania, Zambia and Zimbabwe which are characterized by the miombo vegetation and a unimodal rainfall regime. The research programme has focused on technology development to address small holder fanner problems of declining soil fertility, shortage of fodder and fuel wood environment degradation through deforestation, overgrazing and soil erosion. After nearly a decade of research and capacity building. The network has developed several promising technologies. E.g. sesballla improved fallows, sesbanial maize relay cropping, and maize/gliricidia inter cropping fodder banks. Rotational wood lots for poles and fuel wood and indigenous fruits for human nutrition. Significant maize yield increases have been obtained following 2- to-3-year sesbania fallows or in relay cropping and gliricidial maize intercropping systems. These technologies have advanced to fanners’ fields and currently the network has over 1000 experimenting farmers most of whom are testing the sesbania improved fallows Fanner enthusiasm and e-expectations from these tec1mologies are high throughout the network. In addition, several MPTs have proven themselves in terms of biomass production for fodder and positive effect on live weight gains in goats further. The network has evaluated over 20 species of indigenous fruits several of them have easily been propagated and have given fruits within 18 - 24 months of transplanting. Priority indigenous fruits in the region are Uapaca klrkiana and Sclerocarrya birrea Uapaka has been collected from five southern African countries for evaluation and improvement before distribution of planting materials to fanners. Future thrusts will focus mainly on extension and refining of the best technologies as well as research on strategic issues such as nutrient dynamics in the systems being developed and implication on the sustainability of the systems under farm management.Item Agroforestry Trees for Nutrient Cycling and Sustainable Management(1996) Buresh, J. R.; Jama, B.; Ndufa, J.K.The integration of trees with crops can influence both the supply and availability of nutrients in the soil. Trees can increase the supply of nutrients within the rooting zone of crops through (i) input of nitrogen (N) by biological N2 fixation, (ii) capture and "pumping up" of nutrients from below the rooting zone of crops and (iii) reduction in nutrient losses by leaching and erosion. Trees can increase the availability of nutrients through increased release of Nutrients from soil organic matter (SOM) and recycled organic materials. Roots of trees frequently extend beyond the rooting depth of crops. The potential of deep-rooted trees to capture subsoil nutrients is (i) greatest when trees have a high demand for nutrients, (ii) greatest when high amounts of plant-available nutrient are present in the subsoil and (iii) greater for mobile nutrients like nitrate, than for less mobile nutrients, like phosphate. Nitrate can accumulate below the rooting depth of annual crops when (i) production of the crops is limited by pests and nutrients other than N and (ii) subsoils contain anion exchange sites to sorb the nitrate. Recent research showed that Sesbama sesban is very effective in taking up accumulated subsoil nitrate. Sesbania is also more effective than natural grass fallows in extracting subsoil water, which suggests that the potential for leaching loss of nutrients is less under sesbania than natural fallows. Other research showed that fast-growing trees with high N demand, such as Calliandra calothyrsus, S. sesban and Eucalyptus grandis, are much more effective in taking up subsoil nitrate than slower-growing trees, like Grevillea robusta and Markhamw lutea. The mineralization of SOM is a source of plant-available N and phosphorus (P) Nutrient release from SOM is normally more dependent on the portion of the SOM in biologically active fractions than on total quantity of SOM. Recent research indicated that the amount of N in the sand-associated fraction of SOM that floats in a dense liquid (referred to as light fraction N) is directly related to the release of N from SOM. Yield of unfertilized maize on a N-limiting soil has been shown to be strongly related to both inorganic soil N before maize planting and light fraction N. Inorganic soil N, N mineralization, and aI110unt of light fraction N were higher after 2 and 3-yr tree fallows that continuous unfertilized maize in Zambia and Kenya Among six tree fallows, inorganic N, N mineralization and light fraction N were (i) higher for the mean of the five N-fixing trees than the one non-fixing tree. (ii) higher for the mean of the two trees with lowest (lignin + polyphenol)/N ratios leaflitter than the two trees with highest ratios in leaf litter, and (iii) higher for S. sesban than the mean of the other trees. Some agroforestry trees have potential to provide sufficient N to sustain moderate crop yields through (i) increased N inputs from biological N fixation and deep capture of nitrate and (ii) effective recycling of N from plant residues and manures. Agroforestry trees, on the other hand, are not likely to provide sufficient P for sustained crop yields. Phosphorus is not fixed from the air like N, and the capture of P from subsoil is typically small. The recycling of P from organic materials is normallyItem Community Participation in Agroforestry Development and Extension: Experience of the Kenya Wood Fuel and Agroforestry Programme (KWAP), Busia District, Kenya(1996) Noordin, Q.This paper discusses the role of the community in agro forestry technology development and the extension approaches that have been used to spread sustainable agro forestry practices. It begins by stressing the importance of active community participation in the development of appropriate and sustainable agro forestry interventions for small holder farmers in the tropics. This is seen as essential because farmers understand their complex biophysical, socio-cultural and economic environment better than anyone else. It is therefore imperative that the community be involved in the whole process of technology development right from problem identification to technology transfer. Similarly, problem identification and prioritisation by consensus of the community is seen as crucial, as.is the role of indigenous knowledge in designing technologies that are cost effective, relevant and easily adoptable. Equally important is that interventions be tried out with a few farmers before involving the whole community and that farmers develop a monitoring system within their means that is effective in assessing the performance of these technologies. The paper concludes that a community-based extension system should be institutionalised in order to ensure sustainability in the transfer of the technologies. The system should be able to lead to the building of the capacity of the local farming community to continue utilising and transferring these technologies to solve their problems and ultimately creating sustainable farming systems.Item Fodder Production under Small-Holder Agroforestry Systems(1996) Karanja, G.M.; Nyaata, O.Z.; Mureithi, J.G.; Wandera, F.P.This paper suggests that the use of fodder multi-purpose tree (MPT) species is a viable option for protein and mineral supplementation for-the “small-holder dairy farms. The paper reviews some past and current research on fodder MPTs in Kenya with regard to choice<5f species, establishment and management and highlights the challenges ahead. Nutrition is the most limiting factor to small-holder dairy production. Napier grass (Pennisetum purpureum), With limited amounts of crop stover and other on-farm roughages, form the basic diet .The quantity, nutritive quality and seasonal distribution, however, do not satisfy the- animal requirements, thus necessitating supplementation. Use of commercial supplements –and inclusion of herbaceous legumes in Napier grass are possible supplemental options but for a variety of reasons, levels of commercial supplement feeding and the adoption 9f herbaceous legumes by the small-holder farmers are very low.Item From Research Plots to Farmer Adoption: approach for Agroforestry Research and Development Interaction(1996) Atta-Kra, K.Traditionally, research and extension/development have existed as separate activities, usually in separate government institutions. Conventional wisdom has always seen research as generating technologies and passing on these technologies to the development and extension organisations for transfer to farmers. In several instances, especially in the case of farming systems and natural resource management technologies (e.g. agroforestry), this simplistic model has not worked. There has always been a gap between research and development, which tends to work against the whole concept of technology transfer. This phase of research development interaction is termed in this paper as developmental on-farm research (devOFR). The paper presents dev-OFR as a legitimate component of research and argues that it is essential for enhancing technology transfer for impact development of agroforestry research.Item Nitrogen-Fixing Trees in Agroforestry Systems: Myths and Realities(1996) Odee, D.W.The need to increase crop production on sustainable basis IS crucial in the tropics because of poor soil fertility as characterised by low nitrogen and phosphorus status. Agroforestry entails inclusion of woody perennials (trees and shrubs) in a diversified and sustainable land-use system. Use of nitrogen-fixing trees and shrubs (NFTs) in agroforestry systems is specifically to conserve the production potential of such systems due to the inherent ability of NFTs to improve the nutrient status of the soil. Appropriate manipulation and management of the micro-symbiont and macro-symbiont enhances biological nitrogen fixation (BNF) in an agroforestry system that incorporates NFTs as tree/shrub components. This paper highlights the technologies available for ensuring optimal exploitation of BNF in the agroforestry context and also points out some of the misconstructions about nitrogen-fixing symbiosesItem Status of Agroforestry Research in Kenya(1996) Nyaman, D.O.; Kenya Forestry Research InstituteThe paper reviews the status of agroforestry research and development in Kenya over the past 2 decades evolving from a simple rotational sequence of temporal agroforestry to intensive and complex multi-storey Systems In all these developments, the most distinctive element and point of focus ,s seen as the contribution of the multipurpose woody species (trees and shrubs). Agroforestry during this period has undergone transformation from a mere descriptive study into one requiring a more scientific approach. Subsequent development in agroforestry research has focused on three key areas: characterisation and analysis of land use/farming systems, agroforestry technology development and systems improvement and assessment, screening, management and evaluation of MPT's. The paper exams major achievements in research as well as the constraints contributing to the s low rate III the development of research in agroforestry The principal constraints Identified Include methodological difficulties coupled With the socio-economic and ecological complexity that are inherent III agroforestry systems. Particular attention is focused on participatory, analytical and multidisciplinary characterisation as a first step III agroforestry research finally, the paper stresses the need for additional research effort to be focused on key agroforestry technologies, in terms of adaptability with farmers, and to provide the basis for developing a decision support system package.
