Journal Articles

Permanent URI for this collectionhttp://localhost:4000/handle/20.500.12504/203

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Reactions of pineapple cultivars to pineapple heart rot disease in central Uganda
(Elsevier: Crop Protection., 2020-09) Oculi, J.; Bua, B.; Ocwa, A.
Pineapple (Ananas comosus (L.) Merr.) is an important fruit crop in Uganda ranking third as a major fruit crop after banana and citrus globally. However, pineapple production in Uganda is threatened by the recent outbreaks of pineapple heart rot disease (PHRD). Pineapple heart rot disease is the most widespread and devastating disease of pineapple in Uganda and can cause tremendous yield loss. Information on the sources of resistance is still scanty in Uganda. Additionally, no study has been done in Uganda which point out whether variety influences disease severity. Therefore, the objective of this study was to assess the reaction of pineapple cultivars to pineapple heart rot disease in central Uganda. Five cultivars of healthy pineapple suckers were planted in the field in a randomized complete block design (RCBD) to screen for resistance to PHRD. No significant (p > 0.05) difference in PHRD incidence was recorded in week two and week 4 of the experiment. However, there was significant difference (p < 0.001) in incidence of PHRD from week 6 up to week 12 of the experiment. Additionally, PHRD severity varied significantly (p < 0.001) from week 6 up to week 12. Cultivar Smooth Cayenne recorded low severity and is therefore promising. All the five pineapple cultivars were susceptible to PHRD though with varying levels of incidence and severity. Therefore, there is need for additional studies to establish the suitability of Smooth Cayenne as a source of parental donor in breeding for resistance to PHRD.
Response of common bean genotypes grown in soil with normal or limited moisture, with special reference to the nutrient phosphorus
(MDPI : Agronomy, 2018-07-30) Namugwanya, Margaret; Tenywa, John Stephen; Otabbong, Erasmus
Drought and phosphorus deficiency in the soil are the major production limitations of common beans (Phaseolus vulgaris L.) in Sub-Saharan Africa. This study measured the yield responses of low phosphorus-tolerant common beans to drought stress. A field experiment was conducted under two drought conditions codenamed, non-drought-stress (NDS) and drought-stress (DS). The former was located at Mukono Zonal Agricultural Research and Development Institute (MUZARDI) in Mukono District, characterised by rainfall of more than 400 mm season−1. The latter was situated at Wabinyonyi in Nakasongola District, characterised by less than 300 mm season−1; both in central Uganda. Treatments included the two study conditions (NDS and DS); and four test bean genotypes, AFR703-1, AFR 708, JESCA, and MCM 2001, against a local check, K131. A water deficit of 156 mm season−1 was observed in the DS site causing a drought intensity index (DII) of 40%. That pattern contrasted considerably in the NDS site where the actual rainfall did not significantly (p > 0.05) vary from the required water by the bean plant. Whereas genotypes AFR703-1 and AFR708 out-yielded the local check in NDS by 213 and 681 kg ha−1, respectively; their grain yield harvested was comparable to the control yield in DS. When grown under DS, low P-tolerant beans, especially the AFR703-1 and AFR708, survived drought stress through faster development by reducing the number of days to flower, reach physiological maturity and develop seeds. AFR703-1 and AFR708 sufficiently withstand drought stress, and are therefore recommended for inclusion in cropping systems that are characteristically constrained by the combined soils’ P deficiency and/or drought.
Review of the land use and climate change impact assessments in semi-arid ecosystems in Africa: Opportunities and challenges
(Water and Environmental Sustainability, 2023-12) Chisadza, Bright; Musinguzi, Simon Peter; Gwate, Onalenna; Malinga, Wayne
Despite the existing literature on climate variability (CV) and land use change (LUC) impact assessments, understanding their effectiveness in semi-arid regions remains challenging. This review aims to assess the effectiveness of CV and LUC impact assessments in guiding adaptation options for smallholder farmers in semi-arid ecosystems and associated challenges and opportunities. We conducted a systematic literature review, primarily using Google Scholar, to examine the impact of LUC and CV in African semi-arid ecosystems. We employed Vos Viewer to analyze the relationships among the identified sources. Our findings reveal that current assessment approaches often fall short in capturing the intricate interactions within semi-arid ecosystems. These assessments frequently emphasize biophysical productivity, employ reductionist modeling methods, and neglect the social, economic, and adaptive aspects of these systems. Our review underscores the importance of integrating CV and LUC in impact assessments. While a majority of studies concentrate on CV adaptation (26%), they often overlook the pivotal role of LUC and their interplay with climate impacts. Only a small fraction (2%) integrates CV and LUC in impact assessments. Assessing the benefits of CV and LUC impact assessments presents mixed results, particularly for smallholder farmers. While global and regional benefits are discernible, quantifying these advantages at the local smallholder farmer level remains challenging due to diversified land use and small-scale operations. This highlights the need for localized studies addressing the specific challenges confronting smallholder farmers in semi-arid regions. To enhance assessments effectiveness, we recommend for more interdisciplinary research and the application of a complex systems approach, integrating GIS and remote sensing.
Soil moisture dynamics under different tillage practices in cassava–sorghum based cropping systems in eastern Uganda
(Elsevier: Ecohydrology & Hydrobiology, 2013) Mulebeke, Robert; Kironchi, Geoffrey; Tenywa, Moses M.
Soil moisture storage in the root zone determines availability of water in crop production, but there is limited attention on water resource management in cassava–sorghum production systems. Soil moisture content was higher under ripping than mouldboard ploughing. Mouldboard ploughed plots had more moisture in the upper (0–10 cm) layer while, the ripped plots accumulated more moisture in the lower (20–40 cm) root zone. Soil surface roughness was stable two months after ploughing. Crop combinations and seasons influenced soil moisture storage over the growing period. The different cropping systems vary in their soil moisture extraction capacities at different growth stages, hence influencing the overall moisture storage and water used in the root zone.
Soil organic carbon and nitrogen decomposition in fecal manure of cattle fed browse/maize silages
(Sustainable Agriculture Research, 2014) Kato, , Habib; Mulebeke, Robert; Bareeba, Felix Budara; Sabiiti, Elly Nyambobo
Soil organic carbon (C) and nitrogen (N) decomposition in fecal manure of cattle fed browses of Calliandra (Calliandra calothyrsus), Gliricidia (Gliricidia sepium) and Leucaena (Leucaena leucocephala) browse/maize silage mixtures and maize (Zea mays) silage alone when applied to the soil were investigated in a pot experiment in comparison to the corresponding silages fed. Maize silage alone had the lowest N and a larger C: N ratio, making it a poor quality compost when applied to the soil, but compared to the browse/maize silage mixtures it had the highest level of soluble N as non-protein nitrogen (NPN) which makes much of its N available for soil microbial decomposition of its organic C. Calliandra browse/maize silage mixture had the highest level of fiber-bound N (ADFN), which reduces N availability for soil microbial decomposition of its organic C in spite of its high N content and a narrower C: N ratio. Fecal manure from maize silage alone had a lower level of N and a wider C: N ratio than fecal manure from the other silages fed which would affect its decomposition in the soil, but it had the lowest level of ADFN and much of its N is made available for soil microbial decomposition of its organic C. Soil samples after 12 weeks of the experiment showed that Calliandra browse/maize silage mixture maintained the highest level of C in the soil, while maize silage alone maintained the lowest level. Also soils treated with fecal manure from the other browse/maize silage mixtures maintained higher levels of C than fecal manure from maize silage alone. Organic C levels were lowest at 8 weeks of the experiment for all treatments and rose to the original levels at 12 weeks which could have been as a result of biotic and hydrologic factors coupled with soil aggregation. Decomposition of organic N followed a similar trend as organic C. The two elements are linked in both plant inputs in the soil and in the eventual soil humic substances. The soils treated with browse/maize silage mixtures maintained C: N ratios that were similar to that of the control soil and higher than those of the fecal manure treatments. Thus, in spite of the added silage materials to the soil, rapid decomposition of organic C could not occur to reflect benefits of adding the silage materials to the soil. Thus, fecal manure, particularly from feeding animals on browse/forage diets is more beneficial in the soil as it would decompose more readily releasing the plant nutrients they contain.

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