Guazuma crinita is an important timber tree with a rotation age of 6–12 years in the Peruvian Amazon. A provenance/progeny test containing 200 families from seven locations (provenances) in the Aguaytía watershed of Peru was established in three zones in the Aguaytía watershed that differ in mean annual rainfall and soil fertility. Farmers managed the replications as plantations. Replications were divided into two groups at 24 months: faster- and slower-growing plantations. The faster-growing plantations were thinned at 32 months. The objectives of this paper are to determine if genetic variation in growth traits (tree height, stem diameter) is relatively greater in the faster-growing plantations, and if there are significant differences in tree mortality and stem bifurcations among provenances and families at 24, 36 and 48 months. Variation due to provenances and families and heritability of growth traits were consistently greater in the faster-growing plantations. At 48 months, heritability of growth traits was about twice as large in the faster- than in the slower-growing plantations. There were no significant interactions between zones and either provenances or families. Tree mortality and stem bifurcations in the faster-growing plantations generally did not differ significantly among families, but did differ significantly among provenances. Based on these results and considering its rotation age, we recommend that G. crinita families/trees could be selected at 48 months in the faster-growing plantations, the plantations could be transformed into seed orchards and the seed could be used for reforestation throughout the Aguaytía watershed. Results are compared with other tropical hardwoods.
Tag: Environment
Community visioning and action planning: guidelines for integrating the options by context approach
The Drylands Development Programme (DRYDEV) is an integrated programme designed to improve livelihoods and landscapes in semiarid areas of selected countries in the Sahel and Horn of Africa. It is a fiveyear initiative (August 2013 to July 2018) that aims to support smallholder farmers in selected dryland areas of Burkina Faso, Ethiopia, Kenya, Mali and Niger with contextuallyappropriate interventions. Thus, the programme strives to support farmers to pursue options that are informed by the realities of the local context and their own priorities. To fulfil this objective there is need to establish an optimal balance between expert knowledge and farmer priorities. The identification and implementation of appropriate interventions in any particular community presupposes the involvement of the local people. Equally important are the principles of inclusiveness and bottom-up processes. Hence, the programme facilitates community level visioning and action planning involving all the different categories of farmers as a way of identifying options/ interventions and learning priorities. In addition, the initiative has adopted a co-learning paradigm, using participatory processes to select, refine and review the contextual appropriateness and performance of various options. This means that the identified options might not be the best fit in the beginning of implementation, but could be refined and adapted or dropped as understanding of the local context increases.
Property rights, risk and livestock development in Africa
This book documents the proceedings of the International Symposium on Property Rights, Risk, and Livestock Development. The symposium was held to appraise progress, review achievements, and identify remaining research gaps at the conclusion of a three-year research project led by the International Livestock Research Institute (ILRI), the International Food Policy Research Institute (IFPRI), and the University of Goettingen. The goal of the project was to support appropriate reforms of property institutions and land policies in the semiarid areas of Sub-Saharan Africa. The objectives werea) to better understand how environmental risk affects the use and management of resources under various property-rights regimes,b) to identify circumstances under which different pathways of change in land use and property rights are followed, andc) to identify how policy and other external interventions can help communities achieve desirable pathways and mitigate negative impacts of undesirable pathways.The introductory chapter provides a description of the research, development, and policy context that shaped the formulation of the project’s goal and objectives; a summary of the research approach taken in the project; and a discussion of how the papers presented in this book relate to the project’s objectives.
Weed population in cowpeas (Vigna Unguiculata) (L) Walp) as influenced by water table, moisture regime and cultivar
Experiments were conducted during the 1987-88 dry season to determine the influence of irrigation water and naturally occurring water table depths in a toposequence, on the weed ecology of two cowpea [Vigna unguiculata (L.) Walp] cultivars at Los Banos, Philippines. In the line source sprinkler irrigation experiment on a Typic Tropudalf, saturated and wet treatments had a higher weed population than the dry treatment. In the toposequential agrohydrology experiment, the shallow and medium water table depths had greater weed populations than the deep water table depth regime. In both experiments the early maturing cultivars had a higher LAI [leaf area index] in their early phase of growth. This was associated with reduced weed competition as compared to the medium maturing cultivars, irrespective of moisture regimes.
Economic framework for integrating environmental stewardship into food security strategies in low-income countrie: case of agroforestry in southern Africa region
One of the greatest challenges in many Sub-Saharan Africa countries especially where seasonal food deficits occur frequently, is how best to achieve a balance between the goals of food security and agricultural production on the one hand, and the concerns for the conservation of environmental quality and natural resources capital on the other. A number of agricultural production technologies (based on natural resource management principles) exist that offer opportunities for achieving the two seemingly divergent goals because they have the characteristics to produce joint multiple outputs, i.e, they produce food and provide environmental services. However, farmer adoption of these technologies has generally been limited. Drawing from natural resource economics, this study presents a conceptual framework that provide environmental-economic logic for establishing incentives that internalize the environmental services produced by multiple-outputs land use technologies. Using a land use practice based on agroforestry principles (that is, “improved tree fallows”) as a case study, this paper synthesizes studies carried out in southern Africa region for over a decade. It then discusses how the potential impacts of the technological advances made in research and development are affected by policy and institutional constraints, among other challenges. With particular emphasis on the socio-economic context in southern Africa, the paper identifies options for addressing these institutional and policy constraints in order to facilitate adoption of multi-output land use practices by farmers and unlock their potential to meet food production goals for individual households and environmental services for the wider society.
Integrated physical socio-economic and environmental planning vol. 10
Soil biology processes in tropical ecosystems
Describes the processes which maintain the integrity of natural ecosystems and the mechanisms buffering the potential effects of climate extremes and other perturbations on soil and nutrient losses. The Tropical Soil Biology and Fertility Programme reference sites represent a wide range of systems which are persistent under very different climates. The derived cropping systems are also sustainable provided that certain key ecological properties are maintained. These include a basic complement of plant life forms, persistent rooting systems in high rainfall zones, maintenance of litter and soil organic matter pools, and long-term balance of nutrient gains and losses. Traditional (low external input) farming systems, which usually involve a high diversity of plant species, often include management practices based on the intuitive understanding farmers have developed around these principles. Intensification of these systems, and long rotation (tree) crops have frequently resulted in declining yields as a consequence of one or more component parameters of the system becoming uncoupled or falling below optimal levels to maintain soil properties and proceses. In order to develop more sustainable cropping systems, optimising the use of scarce internal and external resources, the critical levels of soil properties and ways of managing soil processes need to be determined
Global C- a beginner’s model of global carbon stocks and flows
The Global C model accounts for carbon stocks in the atmosphere, in terrestrial ecosystems, the ocean and fossil form, and the major exchanges between these. CO2 and some other gasses (held constant in this model) have a ‘greenhouse’ effect, reducing the amount of long-wave radiation that can leave the planet earth, thus increasing its temperature. A change in atmospheric CO2 can be by this mechanism lead to a change in global temperature (global warming or global cooling). Temperature itself has an impact on a range of biological processes in C sequestration by plant growth and C dissipation by decomposer activity. The oceans contain by far the largest C stocks, but only a small part of this, in the upper ocean layers, interacts with the atmosphere. Potentially the oceans can absorb CO2 brought into the atmosphere by changes in terrestrial stocks or use of fossil fuel, but the rate, at which such absorption can occur, is limited by the equilibration processes.
Recognising local knowledge and giving farmers a voice in the policy development debate
One of the aspects of poverty as currently defined is the lack of voice or the lack of empowerment and the feeling of not being able to take events into one’s own hands. This aspect of poverty is difficult to quantify as yet, but it is an important element in the debate on the rural poor, deforestation and natural resource management. In this lecture note we will introduce: •methods to collect and appraise farmers’ ecological knowledge in a formal manner and analyse the way this knowledge and value system complements the more formalised science we have discussed in other Lecture Notes; •methods to get the views of local communities on the options they have and the constraints they face more explicitly represented, and •ways to get the farmer’s ‘voice’ heard in dialogues with local and national policymakers.