Crown and root pruning of four year old boundary trees at Siaya and Nyabeda in Western Kenya: socio-economics, utilization of soil water, and maize and wood yields
| dc.contributor.author | Tefera, Almaz Tekleberhan | |
| dc.date.accessioned | 2023-05-19T11:07:23Z | |
| dc.date.available | 2023-05-19T11:07:23Z | |
| dc.date.issued | 2004 | |
| dc.description | PhD Thesis | en_US |
| dc.description.abstract | Farmers' survey and two field experiments were carried out at Siaya and Nyabeda in western Kenya to investigate the effect of crown and root pruning on tree growth. soil water dynamics, maize and wood yields, when trees are boundary planting along agricultural crops. The experiment carried out at Siaya included 4 years old trees of Casuarina equisetifolia. Eucalyptus grandis, Grevillea robusta and Markhamia hitea while the one carried out at Nyabeda involved 5 years old G. robusta. The following parameters were assessed over 5 and 4 cropping seasons at Siaya and Nyabeda respectively: tree growth, light interception, soil water dynamics, tree water uptake and maize yield. Results from the Siaya survey showed that 74% of the farmers grow M. hitea on their farms, which is an indigenous tree species in western Kenya. Eighty-four percent of the respondents observed that crop yields that are close to the trees were very low compared to crops that were far away from the trees. The result from the experimental data showed that all the four tree species in the test at both sites survived both heavy crown and root pruning without any mortality or reduced growth. Tree species showed significant (P<0.001) variability in branch biomass produced from crown pruning at Siaya site. Eucalyptus grandis had the highest biomass (107.2 kg/tree) production at the time of first pruning while M. lutea had the lowest (5.5 kg/tree). New branch sprouts of pruned trees continued to grow in both length and diameter. Eucalyptus grandis had the highest growth in both new branch length and basal diameter (10.49 m and 13.44 cm respectively) while M. lutea had the least (5.39 m and 6.75 cm respectively). Soil water under crown and root pruned trees were significantly (P<0.05) high compared to the unpruned (control) tree plots. Soil water content decreased by 25-35% under un-pruned (control) tree plots of all species as compared to soil water content under crown and root pruned tree plots. Transpiration of crown and crown plus root pruned C. equisetifolia and G. robusta trees was reduced by 50% as compared to unpruned trees. Maize grain yield was positively influenced by photosynthetically active radiation (PAR) under both C. equisetifolia (R2 = 0.84) and E. grandis (R2 = 0.97) boundary trees. During the first 3 maize cropping seasons, maize crops adjacent to pruned trees produced significantly (P<().01) higher yield (50-80%) compared to that growing adjacent to the unpruned (control) trees. Based on maize yield production, crown only pruning is recommended for M. lutea and E. grandis trees while crown plus root pruning is recommended for C. equisetifolia trees. Root only pruning is recommended for G. robusta trees. Trees of all species need to be re-pruned every 1-2 years. | en_US |
| dc.description.sponsorship | ICRAF, IFS and DFID | en_US |
| dc.identifier.uri | http://www.suaire.sua.ac.tz/handle/123456789/5269 | |
| dc.language.iso | en | en_US |
| dc.publisher | Sokoine University of Agriculture | en_US |
| dc.subject | Pruning | en_US |
| dc.subject | Trees | en_US |
| dc.subject | Siaya | en_US |
| dc.subject | Nyabeda | en_US |
| dc.subject | Western Kenya | en_US |
| dc.subject | Thesis | en_US |
| dc.title | Crown and root pruning of four year old boundary trees at Siaya and Nyabeda in Western Kenya: socio-economics, utilization of soil water, and maize and wood yields | en_US |
| dc.type | Thesis | en_US |