Tag: faidherbia albida
Plot-Scale Biophysical Modelling of Tree-Crop Interactions Using APSIM
Separating the effects of trees on crops: the case of Faidherbia albida and millet in Niger
Faidherbia albida (Del.) A. Chev. is an important tree species of the scattered tree or parkland systems in the Sahel. The improved crop growth under its canopy is well known, and has been attributed to various components notably: higher soil fertility, improved microclimate and better soil physical properties. The relative contributions of each of these components are not known, but knowledge about this is essential for making proper decisions concerning management options. The overall tree effect on crop production (expressed as fraction of the sole crop production) is analysed here as a weighted sum of (positive and negative) relative net tree effects on the resources for crop growth. In this sum, the weights reflect the degree of limitation of the resources in the environment at the tree-crop interface. The paper shows how the relative net tree effects and the accompanying weights can be estimated from field experiments. In an on-farm field experiment in Niger, millet production under the F. albida canopy was about 36% higher than in the open field. The nitrogen availability under trees was estimated to be more than 200% higher than in the open causing a 26% production increase. The phosphorus availability was estimated to be almost 30% higher and because of its high limitation causing a production increase of 13%. The net effect via other resources (notably light and water) was negligible (3% production reduction) and not significant.
Carbon and economic benefits of community management of dry forests in Tigray, Ethiopia
Community management of forests may help meet human subsistence needs and mitigate climate change. The study was conducted to quantify the potential of community managed forests to accumulate carbon and simultaneous increase income. Twenty-four plots were randomly selected from managed natural forest, disturbed natural forest, exclosure and grazing land to quantify biomass and carbon. Tree and shrub biomass was estimated using a regression model while herbaceous biomass was determined using a total harvest. The impact of community forest on total income of the community was studied by taking landless sample households. A Propensity Score Matching (PSM) was conducted to measure the impact of the community forest on total income of the users. The estimated total biomass for managed natural forest, disturbed natural forest, exclosure and grazing land were 92.9 Mg ha-1, 33.4 Mg ha-1, 33.8 Mg ha-1 and 12.5 Mg ha-1, respectively. There was a significant difference in total biomass between the community forests and the grazing land (P<0.05). The carbon content of the living biomass for managed natural forest, disturbed natural forest and exclosure were estimated as, 43.6 Mg ha-1, 15.7 Mg ha-1, 15.9 Mg ha-1, while for open grazing the estimated carbon were 5.8 Mg ha-1. The carbon trading potential for managed natural forest, disturbed natural forest and exclosure was US
Provenance and pretreatment effect on seed germination of six provenances of Faidherbia albida (Delile) A. Chev
A nursery experiment was conducted to determine the effects of seed pretreatment methods on the germination of Faidherbia albida at ICRAF, Nairobi from six provenances consisting of Awassa, Taveta, Lake Koka, Maseno, Chinzombo and Wagingombe. Seeds were subjected to five pretreatment methods namely nicking, soaking in acid, hot water, cold water and control. Germination percentages (GP), mean germination time (MGT) and germination index (GI) were calculated and the data was subjected to ANOVA. The study revealed significant (p 0.05) differences in seed treatments among provenances in all studied parameters. Highest germination among pretreatments in Awassa (99 %) and Wagingombe (80 %) was observed in nicked seeds, Chinzombo (81 %) in nicked and acid treated seeds, Lake Koka (90 %) in acid treated seeds and Taveta (28 %) and Maseno (64 %) in cold water treated seeds. Nicking gave the highest cumulative GP (69.67) while lowest GP was observed in hot water treated seeds (23.17). Acid treatment exhibited lowest MGT (8.85 days) and highest GI (2.29) while highest MGT (24.35 days) and lowest GI (0.31) were observed in control and hot water treatment respectively. Although acid treatment gave a high GP and lowest MGT and GI, nicking and soaking in cold water for 24 h is being recommended as cheaper and less hazardous pretreatment methods to improve germination in F. albida since sulphuric acid is expensive and requires proper handling techniques. Significant correlation between geo-climatic data and germination parameters of seeds subjected to different pretreatments indicates that provenances are as important as pretreatments in germination of the species. © 2016 Springer Science+Business Media Dordrecht
Genetic variability and divergence of seed traits and seed germination of five provenances of Faidherbia albida (Delile) A. Chev
Establishment of Faidherbia albida trees on farm is often difficult despite the plant survival adaptive mechanisms such as drought and disease resistance. Adoption of the tree to agroforestry systems is also limited due to lack of knowledge on genetic variation of its provenances. Morphological charac-terization of F. albida provenances is therefore necessary to screen for natural genetic variation in seeds traits for selection of germplasm for long term agroforestry, timber production, fodder, soil fertility increment and environmental sustainability. In this study, seed traits of five provenances of F. albida: Taveta Wangingombe, Lupaso, Kuiseb and Manapools were examined. Divergent studies were analyzed based on seed morphology and geo-climatic conditions of the provenances. Seed length, width, thickness and weight were analyzed to determine the extent of phenotypic and genotypic variance and heritability. This study revealed significant differences among provenances (P=0.05) for all the studied characters indicating substantial genetic variability. Genetic variance for all seed traits was higher than environmental variance suggesting that the expressions of these traits are under genetic control. This result was supported by high heritability values for seed length (0.92), width (0.99), thickness (0.99) and weight (0.99). Seed germination test involved 4 replicates of 25 randomly selected seeds per provenance. Mean germination percentage among provenances was 83.3% with the highest being 97% and the lowest 71%, P=0.05. Relationships among these variables were analyzed using principal component analysis and cluster analysis resulting in separation of provenances into three distinct clusters. Manapools (760 mm), Lupaso (1165 mm) and Wangingombe (628 mm) with high rainfall were placed in cluster one. Taveta (545 mm) cluster two and Kuiseb (0.5) for all traits suggests that selection based on morphological traits can be made with a high degree of confidence.
Arbuscular mycorrhizal association and growth response of Faidherbia albida (Del.) A. Chev. as influenced by land use type in Northern Ethiopia
The distribution and density of mycorrhizal fungi are highly influenced by the type of vegetation and land use types. This study was carried out to study Arbuscular Mycorrhizal (AM) fungi status of Faidherbia albida trees grown at three different land use types (area exclosure, grazing and cultivated lands). Soil and live fine roots were collected from the rhizosphere soils of F. albida trees. AM root colonization percentage were determined using the grid line intersect method. Spores were extracted from 100g of air-dried sub-samples by wet sieving and decanting method. Pot experiment was set up in a greenhouse using completely randomized design with four treatments and replicated three times. There was a significant difference on AM colonization among F. albida tree roots grown on different land use types (P<0.0086). Colonization of F. albida roots were higher in area exclosure (71.1%) followed by grazing land (66.5%) and cultivated land (66.1%). Similarly, spore abundance count was significantly higher (P<0.0014) in area exclosure (3041 100g-1 of dry soil), followed by cultivated land (2002 per 100g-1 of dry soil) and grazing land (1364 100g-1 of dry soil). Soil samples collected from cultivated land showed higher number of spores with low AM colonization compared with grazing lands, which implies low level of infective AM populations in cultivated lands. Glomus was the dominant genus identified in all land use types. AM inoculated F. albida seedlings showed significant growth enhancement compared to the control treatments (P<0.05). Growth enhancements of seedlings inoculated with AM fungal inoculums collected from area exclosure was, however, higher than those collected from grazing land and cultivated land. This emphasis the importance of native soil AM potentials in area exclosure and grazing land for better combinations of F. albida seedlings with AM fungi species to achieve optimum plant growth improvement and rehabilitation of degraded lands.