School of Biosciences (Biosciences) Collections
Permanent URI for this collection
Browse
Browsing School of Biosciences (Biosciences) Collections by Subject "Agriculture"
Results Per Page
Sort Options
-
ItemAmphibian diversity patterns in the Namulonge agricultural landscape(Makerere University, 2017) Akoth, SisiriaUganda’s agricultural landscapes are patterns of cultivated areas and semi-natural elements. Although comprising only a small fraction of the total area, semi-natural elements provide habitats for most of the landscape biodiversity. Agricultural intensification has increasingly destroyed or fragmented semi-natural elements resulting into species decline. Insights into the effects of landscape structure on species’ distributions within and among semi-natural habitats are needed to effectively conserve biodiversity in agricultural landscapes. The influence of land use practices on amphibian species diversity was investigated in areas of intensive and subsistence agriculture in Namulonge for 12 weeks. Amphibians were sampled using Visual Encounter Surveys while environmental parameters were measured using digital multimetre. Altogether, 19 amphibian species were recorded in the Namulonge agricultural landscape. The Mann-Whitney U test showed no significant difference in species diversity between the land use areas. Characteristics of the landscape were used to predict patterns of amphibian species distribution in canonical correspondence analysis (CCA). The model identified plant materials, water and ambient temperature as the most important variables in predicting species distribution. Areas with relatively intact natural vegetation cover supported a few more species than completely converted areas. Such pockets of vegetation provide microhabitat conditions suitable for amphibian species occurrence. The foregoing observation suggests that there is value at landscape-level to preserve natural/semi-natural pockets of vegetation to enhance biodiversity in any agricultural environment.
-
ItemDithiocarbamate residue levels in selected vegetables from Bukavu Region, Democratic Republic of Congo( 2011-03) Muyisa, KavatsurwaThis study involved a survey on the use of dithiocarbamates in agriculture practices in Bukavu Region and the determination of their residues in vegetables (tomatoes and cabbages) from five main sites supplying Bukavu town with vegetables. The survey revealed that mancozeb, traded under the name of Dithan-45 was the main dithiocarbamate widely used, especially in the tomato crops against pests. It was also realised that farmers were not well trained in how to handle the pesticide and as a result, they were not informed of any consequence that could result from the misuse or the mishandling of mancozeb. Analytical method based on HPLC-UV, developed by Codex Committee on pesticide residues was employed for the analysis of mancozeb residues from vegetables samples (tomatoes and cabbages) collected from Bukavu region in DRC. A total of 75 vegetable samples were collected from different fields of five main sites known to supply Bukavu town with vegetables. The laboratory analysis showed a Limit of Detection of 0.01 mg/kg, the recoveries ranged from 73.5 to 82.1 % for cabbages and 64.0 to 66.9 % for tomatoes. The concentration of the residues expressed as mancozeb (the factor conversion for mancozeb derivative = 1.13) in tomatoes varied (in mg/ kg) from no detectable values (ND) to 1.33 for Kamanyola, ND to 1.87 for Nyangezi, 1.44 to 3.99 for Katana, 1.54 to 4.06 for Miti and ND to 4.65 for Mudaka samples. The average values ± SD (Standard Deviation) in mg/ kg for the five study sites were 0.89 ± 0.35, 1.31 ± 0.44, 2.48 ± 1.02, 2.71 ± 0.82 and 3.25 ± 1.25 respectively. The results further show that 24 % of the tomato samples had mancozeb residue values above the MRLs of European Food Safety Authority and 33 % above the MRLs set by EPA, while 73 % were not good for consumption with regards to the maximum permitted level for dithiocarbamates in tomatoes (1 mg/ kg) in Germany. On the other hand, 83% of cabbage samples from all sites had no detectable mancozeb residue levels and the rest had less than 0.1 mg/ kg.