Dataverse World Agroforestry (ICRAF)
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Replication data for: Tree shape plasticity in relation to crown exposure
No full textTrees outside closed forest stands differ in the relation between stem diameter, height and crown volume from trees that grew with neighbours close by. Whether this plasticity in tree shape varies between species in relation to their light requirement is unknown. We purposefully sampled 528 trees ranging 5–100
 cm diameter at breast height growing in a range of light conditions. Across ten broad-leaved species observed in Sumatra or Kalimantan, a generic relationship was found between light exposure of the crown and a light-dependent a l parameter that modifies the height–diameter allometric equation (H = a <sub
class="a-plus-plus">l D b ) from those for closed stands. In our results, vertical stretching is well predicted by light availability. In fully open conditions, trees are on average 31% shorter for the same diameter than under (partial) shade. Most of the stretching response occur
s in all species as soon as some degree of lateral shading occurs. The response, however, varies by species (8–44% reduction) in a way apparently unrelated to species’ successional status. Crown volume varied less than stem height in its relationship with stem diameter across all light conditions tested. The scaling of crown volume with stem diameter, however, differed markedly between tree species
Replication data for: Productivity of Acacia angustissima accessions at two sites in the subtropiProductivity of Acacia angustissima accessions at two sites in the subtropics
No full textLow leaf biomass yields coupled with small land sizes are some of the major constraints faced by smallholder farmers that grow protein-rich fodder trees and shrubs. Given these challenges, availability of highly productive seed sources would be important to enable farmers to produce leaf fodder in sufficient quantities. 14 accessions of Acacia angustissima were evaluated for leaf, wood and total biomass production at two subtropical sites with uni-modal rainfall in ZimbLow leaf biomass yields coupled with small land sizes are some of the major constraints faced by smallholder farmers that grow protein-rich fodder trees and shrubs. Given these challenges, availability of highly productive seed sources would be important to enable farmers to produce leaf fodder in sufficient quantities. 14 accessions of Acacia angustissima were evaluated for leaf, wood and total biomass production at two subtropical sites with uni-modal rainfall in Zimbabwe, with the objective of identifying high leaf biomass yielding accessions. There were up to fourfold difference in biomass yield between the accessions. Leaf dry matter yield ranged from 1.65 to 8.81 Mg ha-1 and 3.7 to 12.4 Mg ha-1 for wood biomass at the higher altitude site (1530 m a.s.l.) but were much lower at 1272 m a.s.l. where they ranged between 0.37 and 4.88 Mg ha-1 for leaf and 0.4 and 7.2 Mg ha-1 for wood. The most productive accessions for leaf biomass were 16231 and 18579 at the higher altitude site, while 18586 and 18501 had the highest yields at the lower altitude. Although no one accession was consistently high yieldin
g across the two sites, the least productive accessions were consistently poor at both sites. The advantage of using selected superior accessions over the unselect bulk seed was up to 85%. These findings underscore the need to promote the use of only high yielding accessions rather than unselect bulk seed. This study identified new, more productive accessions of A. angustissima that potentially widens the genetic base of the germplasm assembled in Zimbabwe
Replication data for: Screening of suitable species for three-year fallow
No full textLegumes can be an important source of N for cereals in tropical, subsistence farming systems that use little or no fertilizers. Out objective was to identify measures of soil N availability, following growth of diverse legumes, that correlated with yield of a subsequent unfertilized maize (Zea mays L.) crop. Unfertilized maize followed nine 3-yr-old systems (six monocultures of planted trees legumes, a groundnut [Arachis
hypogea L.]-maize-soybean [Glycine max (L.) Merr.] rotation, an uncultivated fallow with natural regrowth of vegetation, and unfertilized maize monoculture) in two experiments on a Ustic Rhodustalf in eastern Zambia. Total soil C and N before maize planting were not related to grain yield of maize. Preseason soil inorganic N (NO3 + NH4), aerobic N mineralization, and light-fraction N (N in macroorganic matter, 150-2000 µm and
<1.37 Mg m 3) at 0- to 15-cm depth correlated (P < 0.01) with maize grain yield. Preseason inorganic N combined with light-fraction N accounted for 59% of the variance in maize grain yield. The predictahility of maize yield was slightly improved (64% of the variance) by including the population of the parasitic weed striga [Striga asiatica (L.) Kuntze] with preseason inorganic N and light-fraction N. The results suggest that yield of unfertilized, rain-fed maize following different rotatio
nal systems on a N-limiting soil in an area with monomodal rainfall was strongly related to the additive effects of preseason soil inorganic N and a soil N fraction related to N mineralization
Replication data for: Prototype hedgegrow intercropping systems
No full textFarmers' maize (Zea mays) yields in semiarid Kenya are low because of low and erratic rainfall and soil nutrient depletio
n. An experiment was conducted in Machakos, Kenya, during November 1989–July 1995 to explore the potential of hedgerow intercropping (HI) with Leucaena leucocephala as an alternative strategy to the use of inorganic fertilizers for improving maize yields in semiarid bimodal highlands. The study, conducted in a randomized block design with three replications, evaluated on an operational scale with four treatments: sole maize with or without fertilizer; and HI with prunings of L. leucocephala hedges used as green manure or with prunings and maize stover fed to oxen and manure returned to soil. About 1.4 t ha−1 of L. leucocephala foliar biomass and 1.2 t ha−1 manure were incorporated each season in green-manure and ox-manure systems, respectively. Although sole maize responded to inorganic fertilizer in six of 11 seasons, maize yield was improved by HI, with prunings used as green manure, only once, 5 yrs after the commencement of the study, when rainfall exceeded 500 mm. Over the experimental period, maize yields were 15% and 30% less in green-manure and ox-manure systems, respectively, than in unfertilized maize, primarily because of the competition of hedgerows with crops for water. The fodder system of HI recycled only 27% of N and 50% of P exported from the field in fodder, grain and stover, and depleted nutrients more than the other systems. The green-manure system made a positive N balance, with similar P depletion as in the fodder system. No changes were detected in soil organic carbon or cations in any of the systems during the experimental period while extractable P was significantly improved by fertilizing maize. Net present value of returns from fertilizing maize at 40 kg N and 18 kg P ha−1 was 10% higher than from the unfertilized control. Fertilizer use would be 25% more profitable, however, if P were applied only to match the amount of P removed by crop (9 kg P ha−1 per season) and if maize were not topdressed (amounting to 50% of the recommended N) in poor rainfall seasons. Of the two HI systems, only the fodder system was more profitable than either system of sole-cropped maize because the high value of fodder more than compensated the smaller maize yield obtained in HI. However, the fodder system may not give higher economic returns than a sole L. leucocephala fodder bank. Hence, HI using competitive species such as L. leucocephala and with the level of productivity observed in this study, is not appropriate for semiarid climates to increase cereal yields, either directly through green manuring or indirectly by fodder production and nutrient cycling through livestock
Replication Data for: Determinants of livelihood vulnerability in farming communities in two sites in the Asian Highlands
No full textTo identify the indicators of adaptive capacity that determine vulnerability of households, an intensive investigation was conducted in farming communities at two locations in the Asian highlands. Livelihood vulnerability was assessed, classified to four categories and regressed against current adaptive capacity using logistic regression. Household head’s education, irrigated land, non-agricultural income, and technologies used were associated with adaptive capacity. The strengthening of human, natural and financial capital is identified as the best means of managing risk in farming communities in this mountainous region
Replication data for: Correspondence in forest species composition between the Vegetation Map of Africa and higher resolution maps for seven African countries
No full textQuestion: How well does the forest classification systemof the 1:5,000,000 vegetation map of Africa developed by Frank White correspond with classification systems and more extensive information on species assemblages of higher resolution maps developed for Ethiopia, Kenya,Malawi, Rwanda, Tanzania, Uganda and Zambia? Methods: We reviewed various national and sub-national vegetation maps for their potential in increasing the resolution of the African map. Associated documentation was consulted to compile species assemblages, and to identify indicator species, for national forest vegetation types. Indicator species were identified for each regional forest type by selecting those species that, among all the species listed for the same phytochorion (regional centre of endemism),were listed only for that forest type. For each of the national forest types, we counted the number of indicator species of the anticipated regional type. Floristic relationships (expressed by four different ecological distancemeasures) among national forest types were investigated based on distance-based redundancy analysis, permutational multivariate analysis of variance (PERMANOVA) using distance matrices and hierarchical clustering. Results: For most of the national forests, the analysis of indicator spec
ies and floristic relationships confirmed the regional classification system for the majority of national forest types, including the allocation to different phytochoria. Permutation tests confirmed allocation of national forest types to regional typologies, although the number of possible permutations limited inferences for the Zambezian and Lake Victoria phytochoria. Two forest types from Ethiopia and Kenya did not correspond to regional forest types
Trees for Food Security Project-Local Knowledge-Using local knowledge to understand soil properties and land management in Ongobo bakanisa, Ethiopia
No full textTo design appropriate interventions, it is essential to gain information about the types and the temporal and spatial changes of local soils in the target area and their interaction with trees. Information from soil maps is often not detailed enough to be operational and does not show soil variation within a landscape. The use of local knowledge can help gather information about the various soil types within an area. It does also reveal farmers view on soils and can help understand spatial and temporal changes. This study brings together two approaches to elicit local soil knowledge to inform the ACIAR project "Trees for food security". The AKT5 and InPaC-S methodologies were used to elicit farmers knowledge about soils and land management impacts. Objectives and research questions: Understand spatial and temporal changes of soil properties in the area. 1. Research question: How do farmers classify soils and what are their functions? 2. Research question: What is the spatial distribution of soils? 3. Research question: How did soils change over time? Understand farmers perception of soil soil quality and driving factors for soil quality changes 1. Research question: How do farmers evaluate soil quality? 2. Research question: How does soil management, crop management and trees change soil properties? Find synergies between the methodol
oies AKT5 and modied bits of Barrios` InPac-S tool. 1. Research question: How can the two approaches AKT5 and InPaC-s complement each other
Replication data for: Analyse de la commercialisation des feuilles de Lippia multiflora Moldenke (Bulukutu) à Kinshasa: cas du marché Gambela
No full textAnalyse de la commercialisation des feuilles de Lippia multiflora Moldenke (Bulukutu) à Kinshasa: cas du marché Gambel
Replication Data for: Local Perception on Land Use Systems and Biodiversity in a Rubber Plantation of North Sumatera.
No full textForest area in North Sumatera has declined since many years ago and have changed to more intensive land use systems, e.g. oil palm plantation, rubber monoculture plantation and smallholder. The study of local perception on land use systems and biodiversity was conducted in six villages in Simalungun district, Asahan district, and Serdang Berdagai district, North Sumatera province, to understand local preferences for land-use systems, local perceptions on land-use functions, and values on biodiversity, using Multidisciplinary Landscape Analysis (MLA) approach. The study showed that smallholder rubber and oil palm were the main sources of livelihoods in almost every village, since the two land use systems were important as cash income source. All participants perceived that rubber agroforest was the most important land use, as it could provide sources of income, food and environment values. Peoples understanding on biodiversity was closely associated with livelihood patterns and social life, as biodiversity contributed to their daily needs, and related to specific knowledge. All rubber plots under mixed and monoculture systems were perceived as good value in preventing erosion, while oil palm plots were of relatively low value. Interestingly, people also understood that forest had the highest function as an erosion control as these area are prone to soil erosion due to topography. Local people classified flora and fauna diversity based on their functions, such as food, source of income, fuelwood, construction, medicine, fodder, handycraft and tools, and erosion control. They noticed different biodiversity occured in different land-use types. Rubber agroforests provide all needs, e.g. goods and services, for local communitie
Comparative performance and effect of selected agroforestry tree species on maize productivity in semi-arid Kenya
No full textThis study was carried out to determine performance of selected five agroforestry tree species under different treatments and their effect on crop yield in semi-arid (Juja) Kenya. The aim was to correctly pinpoint at what stage of the trees’ growth they start exacting effect on the intercrop and compare what has been reported on some of the experimental trees elsewhere. The specific objectives of the study are;
1. To assess dynamics of growth of the selected agroforestry trees
2. To determine difference in maize yield near and away from the selected tree