Uganda Journal of Agricultural Sciences

Distribution and Severity of Coffee Pests and Diseases in Central Uganda

Olango, N.D.K. — 2024-11-02

This study aimed to determine the incidence and severity of coffee pests and diseases and any relationships between them. Five coffee producing districts in Uganda, namely, Masaka, Mubende, Mpigi, Kayunga and Luwero were selected. 10 coffee farms were evaluated per district. Pest and disease incidence were determined as the percentage of trees with the disease or pest. Disease severity was evaluated on a 1-5 scale while pest damage was expressed as a percentage of tissue damaged. Results showed significant differences in incidence and damage/severity among all the major pests and diseases in the region except foliage beetles. The most damaging pest was the BCTB with an incidence between 15% and 26%. The next most damaging pests were the tailed caterpillars and Skeletonisers, both lepidoptera with incidence of 20.4% and 16% respectively. The most severe disease was Red blister (Cercospora coffeicola) with a severity score 2.0 and incidence 51.6%. No novel pests or diseases were discovered. Further studies are recommended to understand factors proliferating the pests and diseases.

Impact of tree management on coffee and common bean productivity in smallholder agroforestry systems in Uganda

Joel Buyinza — 2024-11-02

In this study, we hypothesized that tree canopy pruning would positively influence the relative growth performance and productivity of coffee (Coffea arabica L.) and common beans (Phaseolus vulgaris L.) growing under Cordia africana and Albizia coriaria trees. The trees were subjected to a 50% pruning regime at a 6-month interval over a period of 20 months (July 2018 - February 2020), and common beans were introduced following local planting seasons. Yields of parchment coffee were highest under pruned Albizia (949 kg/ha). Unshaded coffee produced the least yield at 402 kg/ha and 422 kg/ha in the Albizia and Cordia sites respectively. While the highest common beans yields (708 kg/ha) were obtained from open field sites, beans that were planted under unpruned Cordia gave the least yield of 420 kg/ha. Unlike coffee, there was a significant variation in yield of common beans across the different management options (P<0.05). The results show that agroforestry tree canopy pruning is an important on-farm management decision for controlling competition while prolonging the period of intercropping in intensive farming systems. Farmers should deliberately prune agroforestry shade trees to minimize the negative effects of dense shading.

Isolation and Characterization of Aeromonas hydrophila lytic Bacteriophages as a safe antibiotic alternative bio-control agent

Raphael Hans Lwesya — 2024-11-02

This study aimed to develop a safe bio-control approach for therapy and decontamination of Aeromonas hydrophila. The study focused on determination of the drug susceptibility of
Aeromonas isolates from diseased tilapia; and establishment of a stock of partially characterized Aeromonas hydrophila bacteriophages. Eighteen (18) Aeromonas spp isolates were tested for antimicrobial resistance against 10 antibiotics. The susceptibility of the isolates to various antibiotics ranged from 0 to 100%. For bacteriophages, three lytic phages that had the highest host range (78.6% to 92.8%, n=28) were selected. Further characterization revealed a burst period of 20 ± 5 to 40 ± 5 minutes, a latent period that varied from 10 ± 5 to 40 ± 5 minutes; and burst size of 98–171 virions per infected cell. There were no significant changes in phage titers on exposure at 40℃ and 50℃ for 60 minutes (P = 0.05). However, a gradual decrease in the titres was observed at 60℃ while a fast decline was noted at 70℃-90℃. All phages demonstrated at least some activity in the pH range of 1-13. In water stability testing, the phages survived up to 22 days of the experiment, with a sharp decrease of 1 log PFU/mL to have been encountered within the first day. The findings of this study suggest phages as bio-control agents against Aeromonas infection in fish. However, further genomic characterization is required.

Potato yield response to tillage practices and inorganic potassium application in South Western Uganda

Rose Mwesige — 2024-11-02

This study examined the effects of minimum and conventional tillage practices and
potassium levels on potato yield in South Western Uganda. Researcher and farmer managed trials were set at KaZARDI and Kariko for three seasons. Varying rates of potassium fertilizer (100, 150, 200, 250, and 300 kg ha-1) were applied in a split plot arrangement with tillage practices as main plots and K rates as the subplots of a randomized complete block design with three replications. Potato growth and yield data was analysed using R-studio version 4.2.0. The findings were that application of 200 kg K ha⁻¹ significantly (P <0.001) increased plant height, the number of tubers per plant, and overall yield per hectare by 12.5%, 27.5% and 21.7%%, respectively. The highest marketable tuber yield achieved was 26.4 t/ha under conventional tillage, compared to 23.3 t/ha under minimum tillage. The interaction between tillage practices and potassium levels was statistically significant, with
traditional tillage showing a stronger response to fertilizer application than minimum tillage. Although minimum tillage resulted in a lower yield, it is cost effective, with a benefit-cost ratio of 3.1.

Efficacy of BioNiKPhos Bio-Fertilizer (NARO BHL BF) on Maize Growth and Yield

Fanuel Ongua — 2024-11-02

This study evaluated the effects of BioNiKPhos Bio-fertilizer (NARO BHL BF) on maize growth and yield, with a focus on determining optimal application rates and economic benefits. The research was conducted at NARL Kawanda and AbiZARDI in Arua, using a randomized complete block design (RCBD). Seven treatment levels were applied (T1: control, T2: 5ml, T3: 10ml, T4: 15ml, T5: 20ml, T6: 25ml, T7: 30ml) per 20L of water, across three replications, over two seasons at NARL and one season at AbiZARDI. BioNiKPhos was applied five days before planting to promote bacterial colonization in the soil. The results revealed that application of BioNiKPhos at 20ml per 20L of water significantly improved maize height, leaf length, dry biomass, grain yield, and 1000 seed weight compared to the control, with a remarkable 32% increase in grain yield. Thus, preplanting application of BioNiKPhos at 20ml per 20L of water was found to be effective in enhancing maize yield by improving soil conditions. Highest value cost ratio (VCR) was obtained from BioNiKPhos at 20ml per 20L of water (2.58). The study recommended application of BioNiKPhos at 20ml per 20L of water as the most agronomically and economically optimum for maize compared to the control.

Agronomic and economic benefits of primary and secondary micronutrients in selected fertilizer applications in rice production in Uganda

Kayuki Kaizzi C. — 2024-11-02

Two sets of trials were conducted during 2020 and 2021 in Amuru sub-county, Amuru District with the following objectives: Set 1 – to determine which secondary and micronutrient limit rice yield; and Set 2 – to compare the yield and economic benefits of applying rice specific NPK blend to application of NP as DAP and urea. Each farmer had one replicate, with other farmers serving as replications. There were 10 to 15 farmers per trial per season. There was a significant increase at p < 5% in grain yield of 2.6 t ha-1 above the control (1.7 t ha-1) with application of a combination of NP with K, Ca, Zn, B and Cu. Omitting either K, Ca, Zn, B or Cu on average resulted in a significant decrease in grain yield (0.74 t ha-1 vs. 4.3 t ha-1 - when all the nutrients were applied) at p < 5% level. The net benefit of adding K, Ca, Zn, B and Cu to NP was Uganda Shillings 1,602,000/=, 739,000/=, 834,315/=, 906,189/=, and 1,057,603/=, respectively. There was a significant increase in rice yield of 1.5 t ha-1 with a benefit to cost ratio of 2 with application of (125 kg DAP + 125 kg urea) ha-1 compared with 2.3 t ha-1 and a B/C of 2.3 with application of (250 kg rice specific NPK + 125 kg urea) ha-1, confirming that rice specific fertilizers are better than application of NP only. The study confirms that micronutrients limit crop yield in Uganda and should be included in balanced fertilizer formulations. Rice specific fertilizers are better than urea and DAP fertilizers recommended by MAAIF.

Agriculture Sector Policy Frameworks and Performance Indicators for Poverty Reduction among Youths in Tanzania

Deogratias Maksi C. — 2024-11-02

This paper reviews the agriculture policy frameworks and their performance indicators for poverty reduction among youths in Tanzania. A systematic literature review and a multivariate analytical approach was applied using principal component analysis. A total of 31 out of 320 articles were selected through a systematic selection process. The findings reveal that the frameworks promised to allocate land, finance and training to youths; provide access to agricultural inputs, improved seeds, fertilizers, knowledge, and mechanization; provision of infrastructures, enhancing market access, promoting technical and entrepreneurship skills; and facilitate linkage between youths and other support initiatives, improvement of social services, and promotion of rural development. The study urges the government and other stakeholders to guarantee youth farmers access to productive resources, subsidized inputs, agriculture marketing, and information and extension services specifically targeting youths. It is important to involve youths in developing agricultural policy frameworks to build their sense of ownership and ensure that their matters are well articulated in the agriculture frameworks.