Makerere University Journal of Agricultural & Environmental Sciences
The mandate of Makerere University Journal of Agricultural and Environmental Sciences (MUJAES) is to disseminate research finds in key areas covering agricultural, food, forestry, and environmental sciences. MUJAES publishes 2 issues per year. Papers are available online, with occasional prints.
Effect of application of witch weed control options on performance of two maize varieties in Uganda
On-farm witch weed (Striga sp.) control management options were tested in Kamuli and Iganga districts in inga infested tields. The objective was to test etticacy of striga control options reported elsewhere unde gandan conditions. A trial was set up with the following treatments: 120 kg N ha' with and without herbicid (Dicamba, a.i. Dimethylamine) application, use of a trap crop (sunflower) and the control. Striga plant population significantly (P<0.05) reduced maize yields. However fertilisers and or with herbicide treatments significantly controlled Striga infestation resulting in increased yield gains. Under sunflower plots in the first season, no Striga plants emerged, however in the following season, sunflower plots were used as the control, Striga emergence was very high leading to significant reduction in yields. Combined use of urea and Dicamba was found to be profitable. Through application of fertilisers and Dicamba a farmer reduced his unit cost of production by 25%. An integrated approach comprising of use of mechanical weeding before flowering in combination with other weed control strategies reported in this paper can tremendously reduce on the soil seed bank. This clearly demonstrates that effective management of Striga can be achieved through an integrated approach.
Copyright (c) 2003 https://creativecommons.org/licenses/by-nc-nd/4.0
The influence of arbuscular mycorrhizae fungus, mulch and fertiliser application on the yield of yams in an agroforestry system in southwestern Nigeria
The effects of chemical fertiliser and arbuscular mycorrhizae (AM) inoculation, and mulching on tuber yield of breeder selected cultivars and unselected landraces of Dioscorea rotundata Poir, and Dioscorea alata was studied in an agroforestry (Tungya) system. The field trials were conducted in three growing seasons (1996, 1997 and 1998) in the derived savanna zone of southwestern Nigeria. Gliricidia sepium trees served as live stakes for yams and source of mulch. The treatments comprised of AM inoculated (Glomus mosseae), non-inoculated, NK fertiliser application, no-fertiliser applications and AM + fertiliser application. Mulching as a treatment factor was added in the third year. The results obtained in the first cropping year showed that both inorganic fertiliser and mycorrhizae applications improved tuber yield for the two selected yam species, with the response to fertiliser application being stronger. The unselected landraces did not respond to mycorrhizal and fertiliser application. In the second year, significant variations (P≤0.05) in tuber yields of all the cultivars were observed but all the three interventions increased yield relative to the control treatment. The third year experiments showed that unselected landrace yields were improved by a combination of mycorrhizal inoculation and fertiliser application and by mycorrhizal inoculation alone but fertiliser application alone had no effect even on selected cultivars. In landrace 1, TDr93-2, and TDr93-31 yields were reduced by fertiliser application. The selected cultivars also responded to AM and fertiliser combined with AM applications. Contrary to expectations, mulching with Gliricidia sepium leaves in the agroforestry system had a detrimental effect on yam tuber yields. However, improved cultivar TDr93-2 had positive yield gains with application of mulch combined with AM inoculation.
Effect of seed clove size and spacing on growth performance of garlic
An experiment was conducted using different size of seed clove and different spacing to investigate their effect on the growth performance of garlic (Allium sativum). The three different clove sizes were large, medium and small planted in four spacings of 25 x 20 cm, 20 x 20 cm, 20 x 15 cm and 20 x 10 cm. Large sized clove produced the tallest plants, longest root, maximum number of leaves/plant and stem length and total dry matter. Plant spacing of 25 x 20 cm gave longest root, maximum leaf number per plant and maximum leaf dry matter while the spacing of 20 x 20 cm gave maximum plant height and root dry matter. Maximum pseudostem length was found from the closest plant spacing of 20 x 10 cm. This study demonstrates that clove site and spacing greatly influence growth performance of garlic. Further studies are proposed to establish optimum clove sites and plant densities that could be recommended to farmers
Screening tomato varieties for phytonutrients productivity and yield performance
Tomatoes (Lycopersicon esculentum Mill) and other vegetables, bean and fruits contain a number of phytonutrients, which are a useful source of energy, metabolic structural material and antioxidants. Additionally, they may boost the immune system or encourage enzymes that detoxify carcinogens. However, varietal productivity with regard to number of fruits per plant and quantity of phytonutrients is largely unknown. A pot experiment was conducted to analyse variety productivity and fruit phytonutrient contents (lycopene, beta-carotene and ascorbic acid such as contents and their relationships in 13 varieties of tomato. Ten varieties were obtained locally and 3 developed by USDA, viz. 97L63, 97L66 and 97L97 (with known high fruit beta-carotene and suited for use in processing applications). The seedlings raised in nurseries were later transplanted in pots (one plant per pot), 5 plants per variety. Lycopene and beta-carotene contents were analysed, using column chromatography and spectrophotometry. Ascorbic acid content was also analysed spectrophotometrically. The statistical analysis revealed that, Hyb-SC-3 and Hyb-Himalata varieties gave maximum fruit yield. Lycopene content was maximum in Anupamam and beta-carotene, in New Uday and all 3 USDA varieties. The variety New Uday also excelled in ascorbic acid content. The positive relationship (r = 0.99) between carotenoid biosynthesis and ascorbic acid content is not clear. Interestingly, the inverse correlation (r = -0.72) between beta-carotene and lycopene confirms that accumulation of beta-carotene in tomato occurs at the expense of lycopene as beta-carotene is downstream of lycopene in the biosynthetic pathway.
Copyright (c) 2003 Prof. M. Masroor, A. Khan, J. Puthukkudi, F. Mohammad, H. Manzer Siddiqui, M. Nacem (Author) https://creativecommons.org/licenses/by-nc-nd/4.0
Seed-borne fungi associated with farmer saved rice seed in Uganda and their effect on germination
Seventy seed samples from three districts of Uganda, namely, Bugiri, Pallisa, and Lira were examined by the blotter method for fungal infection at Makerere University. Twenty different seed-borne fungi were identified and their incidence and infection levels varied significantly (P<0.01) with respect to location and within districts. Bipolaris oryzae was the most prevalent pathogen with an infection range of 3-94%. Phoma oryzae, Pyricularia oryzae, Alternaria padwickii, Fusarium moniliforme, Curvularia lunnata, Nigrospora oryzae, Verticilium cinabarium and Alternaria alternata were also present in all the districts. However, some pathogens were localised. For example, Exserohilum rostratum, and Curvularia eragrostidis were only encountered in Lira and Bugiri districts, respectively. Pallisa district had the least number of fungal species while Bugiri registered the greatest diversity. Mean infections were also low in Pallisa as opposed to Bugiri and Lira districts. Nine categories of seedling abnormality were recorded. Seedlings with shoot and root decay were encountered frequently. B. oryzae, Phoma oryzae, Pyricularia oryzae, A. padwickii, F. moniliforme, C. lunnata, Melanospora zaminae and Alternaria alternata were found associated with 100%, 55.6%, 44.4%, 66.7%, 77.8%, 11.1% and 11.1% of the different abnormalities, respectively. Results of the present study have revealed the occurrence of a wide range of pathogenic fungi and their association with seedling abnormalities.
Germination of seeds of sicklepod as affected by pre-germination treatments, fruit maturity and depth of sowing: Implication in sown fallow management
Sicklepod (Senna obtusifolia) is a multipurpose plant with potentials in improved bush fallow management. Studies were carried out in 1997 and 1998 in the laboratory, nursery and on the field in Ibadan, Nigeria to understand its germination ecology. Studies included germination as affected by: a) pre-germination treatments - sulphuric acid, boiling water and physical scarification, b) fruit maturity, and c) depth of seed burial. Seed coat dormancy was evident in the seeds of sicklepod, especially at dark brown pod maturity stage. Acid-scarification for 2-15 minutes, steeping in boiling water for 10-60 seconds and physical wounding of seed coat resulted in. about 100% germination within four days compared to 20% germination obtained in non-scarified seeds at seven days after sowing. Seeds were not physiologically mature enough until the light brown pod stage. At seven days after sowing, seed germination was 100%, 50% and 0% at 0-4 cm, 8 cm and 16 cm soil depth respectively. Results showed that pre-germination treatments will induce early and uniform germination in sicklepod. The latest stage to remove sicklepod for mulching or green manuring to prevent multiplication of seeds in the soil seed bank is yellow pod stage when the embryo is still immature.
Sicklepod in improved fallow management: Distribution in natural habitat, diversity and phenology
Increasing weed infestation is the primary factor leading to fallow farming, but has not received as much attention as the rejuvenation of soil fertility. Studies were carried out in the early and late growing seasons in 1997 on-farm at Apete in Ibadan, Nigeria, to ascertain the suitability of sicklepod (Senna obtusifolia), a pantropic weed species in improved bush fallow management and in green manuring. Studies included: a) distribution relative to other weed species at seedling recruitment (April and flowering (July) stages in two locations, and b) monitoring of phenology in the natural habitat. Results showed that though the two study locations contrasted with regards to soil fertility parameters, they wère not significantly different with regards to the density of sicklepod. The site average indicated that in April the flora were co-dominated by a number of species with sicklepod accounting for only 23% of the total number of seedlings recruited per m' of the soil seed bank. However, in July sicklepod dominated the flora accounting for about 81% of the total number of plant survivors per m?. The phenological study revealed that sicklepod produced flowers only in the late rainy season. Adaptation to a wide range of soils, delayed flowering/fruiting and good dominance property imply that sicklepod could be used as a green manure and improved bush fallow plant.
An economic assessment of cowpea and groundnut IPM production technologies used by farmers in eastern Uganda
Groundnut (Arachis hypogeaL.) and cowpea.(Vigna unguiculata L. Walp) come seoond and third respectively as the most widely grown legumes in Uganda especially in the northern and eastern regions. However, the yields of these crops have stagnated in recent years, mainly due to pests and diseases. As alternative control methods for pests and diseases, several integrated pest management (IM) technologies that rely on less use of pesticides have been developed and demonstrated on-farm in eastern Uganda for over 7 years, with farmers adopting some of them. The objective of this study was to determine the profitability of groundnut and cowpea IPM technologies. Farm data were obtained from surveys conducted in March-May 2001 in eastern Uganda, where 136 farmers were selected using purposive and random sampling procedures. The profitability of different IPM technology packages for each of the two crops was estimated using the partial budget approach and marginal rate of return (MRR). Results showed that changing from farmers traditional production practices to recommended IPM practices was profitable for both groundnut and cowpea. Marginal rate of return obtained ranged from 108% to 6,671% and 173% to 700% in groundnut and cowpea respectively; all these are well above the minimum accepted MRR of 100%.
Farmer evaluation of an advanced cowpea line for agronomic performance in eastern Uganda
The study explored farmers' assessment of the new improved cowpea line MU-93 against a local cultivar (Ebelat) in terms of yield, pest and disease resistance and farmers' preference for home consumption and market. The study was carried out within the Integrated Pest Management (IM) Farmer Field School environment where the advanced cowpea line MU-93 was used as a resistant component of a cowpea IPM package. The yields of MU-93 were markedly higher than those of Ebelat; unsprayed MU-93 yielded higher than Ebelat, even when Ebelat was sprayed weekly. MU-93 had higher germination percentage, better growth vigor, high leaf and pod production as well as good grain taste. In addition MU-93 had lower pest and disease infestation, higher grain yield, good seed quality and higher market preference. However, it is a late maturing line compared to Ebelat, and after the budding stage its leaves and pods were considered relatively unpalatable. MU-93 also produces fewer but longer pods with bigger grains than Ebelat. Ebelat had moderate germination percentage, early maturity, and had good leaf taste. Basing on the farmers' positive assessment, MU-93 has been submitted to the Uganda Variety Release Committee for possible national release.
Genetic studies and transgressive segregation for large seeds in cowpea
Two cowpea (Vigna unguiculata L. Walp) varieties, Kanannado and IT97D-941-1 with average seed size of 27.0 g 100' seeds and 15 g 100' seeds, respectively, were crossed in the screenhouse. Sufficient backcrosses, F, and F, populations together with the parentals were planted in the field and grown to maturity. Data for 100 seed weight was analysed to determine how this trait can best be improved and also to further understand type of gene effects controlling this trait. Transgressive segregation for large seed was observed in the F, and backcross progeny to the large seeded parent. Large seed was found to be dominant over small seed. Results of the genetic analyses showed the involvement of non-allelic gene interaction in control of this trait. This result further revealed the additive (d) and additive x dominance (j) gene effects as the most important in determining seed size in cowpea. The dominance (h) and dominance x dominance (I) effects were also important but to a lesser extent. Seven gene pairs were estimated to be involved in the control of seed size in cowpea. A narrow sense heritability of 44.2% was estimated for this trait. Genetic advance from F, to F, was estimated as 4.3 g increases in seed size with 5% selection intensity. Selection for transgressive segregates seems to be the best approach for improving seed size in cowpea.
Inter-relationships among potato traits and their significance in determining tuber yield
Research aimed at selecting potato varieties from Standard International Field Trials (SIFT) with high tuber was carried out at five locations during three seasons of 2001 - 2002 in Uganda. Data were collected on number of leaves, number of stems, plant height, percentage tuber dry matter, number of tubers, mean tuber weight and yield. Results from the simple phenotypic correlation and multiple regressions indicated that mean tuber weight (r = 0.61, P<0.001) and number of tubers per plant (r= 0.47, P<0.001) had the highest correlation values and were also retained in the regression equation across all locations, suggesting that these are the most important components of tuber yield. Path analysis was used to estimate the magnitude, significance and directions of causal relationships between these variables and yield; and thereafter an output path diagram developed. Path analysis identified number of leaves, number of stems, percentage tuber dry matter, number of tubers and mean tuber weight as the main yield components, with mean tuber weight (P = 0.62) and number of tubers per plant (P = 0.46), having the highest direct path coefficients. Although the direct effect of plant height on tuber yield was negative, plant height and number of stems per plant were important components of mean tuber weight. Path coefficient analysis also showed that direct and indirect effects of plant traits on yield explained only 47% of the total variation in fresh tuber yield probably due to environmental influence.
Evaporation measurement and validation of meteorological models
Identification of the best-fit meteorological model for evaporation measurement in a particular agroecological zone is a pre-requisite for cost-effective land management. A simulation experiment was conducted at Makerere University with the objective of determining the best-fit model for estimating evaporation. Meteorological data was collected from Makerere Meteorological Station and applied to different models to estimate potential evaporation. Actual evaporation from three mini lysimeters was used to validate models. Actual evaporation from the lysimeter varied between 2.6 to 6.73. mm day!. Results showed that measured actual evaporation was greater in the afternoon than in the mornings and varied significantly (P<0.05) over days. After a linear regression analysis of measured actual evaporation against estimates from meteorological models, models were ranked in the order of best fit as Priestley and Taylor, Makkink, Abtew, Hargreaves, Romanenko, Penman, Turc, CROPWAT, and Penman-Monteith.
Copyright (c) 2002 https://creativecommons.org/licenses/by-nc-nd/4.0
Characterising low production patches in cropped fields of the Kigezi highlands, Uganda.
Intensification of land use has led to land degradation over much of the African highlands. One of the indicators of this degradation are the low production patches of land within cropped fields that have captured farmers' attention and desire for special know-how on their management. The farmers of the Kigezi highlands in southwestern Uganda have a local name, Ebeija, describing the condition of crops growing on these land patches, and relating this condition to soil fertility. Soils from selected low production patches of land in the Kigezi highlands were characterised for their nutrient status by chemical analyses of soil and plant tissue samples, and the limiting nutrient approach in pot and field trials so as to identify the potential soil management needs for these patches. Nutrient concentration levels in soils and bean (Phaseoulus vulgaris L.) foliar tissues indicated that potassium was the deficient nutrient, averaging 0.23 cmolkg and 0.94%, respectively. The limiting nutrient studies indicated best crop yield response (upto 156%) from the combined application of potassium, phosphorus and micronutrients. In smallholder farming systems, such nutrient combinations can best be achieved through integrated fertiliser management.
Linear programming approach to optimal cowpea marketing in Soroti and Pallisa districts of Uganda
Cowpea (Vigna unguiculataL. Walp) is an economically and nutritionally important grain legume in northern and north eastern Uganda. The crop is grown both for subsistance and as cash crop. However, increased production of cowpea as a cash crop will depend on reliable market information. This study was designed to assess the nature of cowpea marketing and establish how optimally it is marketed within the districts of Pallisa and Soroti. Primary data were collected from 72 traders in rural and urban centers of Pallisa and Soroti districts, using pre-tested structured questionnaires. The data were analysed using descriptive statistics and a linear programming (LP) transportation model. The results indicated that a majority of traders were male and sole proprietors. At both wholesale and retail levels, transport costs accounted for the highest percentage of total marketing costs incurred by traders. Poor storage and seasonal fluctuation in demand were among the leading marketing problem. Farmers generally took the largest share of the consumer price. Use of the LP transportation model showed that traders did not optimally distribute their cowpea. The current level of operation was 10% lower than the optimal level. For optimality, Katakwi zone should supply 1164 kg of cowpea to Soroti market. Similarly, Gweri zone should put on the market 2544 kg of cowpea in Soroti. In Pallisa district, Apopong, Putiputi, Ikiiki and Agule cowpea sources would supply only the Pallisa market. The various problems faced in the marketing system were contributing to the difference between the optimal level of transactions and current level.
Integration and dissemination of green manure cover crops in small scale farming systems: Successes and constraints in eastern Uganda
The integration of Mucuna, Lablab and Crotalaria into the farming systems of eastern Uganda was studied in the year 2000. Quantitative and qualitative survey methods of data collection were used with 52 households including former experimenting farmers, and their neighbours. Mucuna, Lablab and Crotalaria were consistently used for 7 seasons, with a mean seasonal use of 15, 10 and 7 experimental farmers, respectively. The quick restoration of soil fertility on the farms, presence of support technologies like clean cassava planting materials, and the selling of green manure seed enhanced crops use. The use of Crotalaria however, dropped from 34% in the first season to 10% in the last season. Constraints to the integration included drought, labour bottlenecks, and storage difficulties particularly for Lablab and Crotalaria seed. The crops had been adapted for domestic and farm uses, with the women dominating their dissemination. Aspects of non-adoption and dis-continuance of the crops were traced to poor farmer group management and lack of information. Soil fertility improvement, sale of seed and size of land were among the factors advanced to explain the integration of crops. Participatory extension can reinforce the existing successes, while an in-depth adoption study of the green manure can be part of further research.
The potential of crop rotation in the management of bacterial wilt of potato in southwestern Uganda
Bacterial wilt (BW) of potato (Solanum tuberosum) caused by Ralstonia solanacearum, is a major constraint to potato production in southwestern Uganda. It is a recalcitrant disease and one of the plausable management options is crop rotation. However, the suitable crops to be incorporated in a crop rotation regime with a view to reduce BW inoculum levels have not been systematically identified. Studies to identify crop(s) that would in the subsequent season delay on-set of wilt, reduce wilt incidence, lower latent infection, reduce Ralstonia solanacearum populations in the soil and increase tuber yield were conducted at Kachwekano Agricultural Research and Development Centre. Trials were carried out for three consecutive seasons during 2000A, 2000B, and 2001A in wilt-infested plots using the randomised complete block design. In 2000A and 2001A all study plots were under potato. The rotation crops (Sorghum bicolor, Triticum aestivum, Zea mays, Eleusine carocana, Ipomea batatas L., Daucus carota, Phaseolus vulgaris and Solanum tuberosum L.) were planted in the same plots during 2000B. Rotation with Sorghum bicolor, Triticum aestivum, Zea mays, Eleusine carocana, delayed on-set of wilt incidence, reduced wilt incidence and latent wilt infestation, and gave higher marketable tuber yield than the other rotation crops evaluated in the study. One-season rotation crops improved the shelf-life of consumption potatoes but not of seed tubers because of latent infections that were detected after subjecting the tubers to incubation at high temperature and indirect enzyme-linked immunosorbent assay on nitrocellulose membrane (NCM-ELISA). Using any one of the evaluated rotation crops was assessed to reduce BW inoculum and was thus better than continuous cultivation of potato.
Farmers' perceptions of pests and pesticide usage in Masaka district, Uganda
A random sample of 60 semi-commercial farmers selected in Masaka district, Uganda, from six counties were interviewed to investigate their perceptions of pesticide usage and pests of crops and animals. The banana weevil, Cosmopolites sordidus (Germar) (Coleoptera: Curculionidae) and nematodes were reported to be the worst pests for the banana (Musa spp.) crop, while the maize stalk borer, Busseola fusca Fuller (Lepidoptera: Noctuidae) was reported to be the major pest of maize (Zea maydis). Many farmers felt that the insecticides they use are sufficiently effective against the pests, the only issue being one of availability. Non-chemical methods of pest control employed in this area include good crop husbandry, like destruction of crop residues after harvest. Only a few farmers were aware of the role of biological control and the significance of weeding in crop pest management.
Seed-borne mycoflora of sesame seeds and their control using salt solution and seed dressing with Dithane M-45
Although seed is key in agricultural production, the seed health status of sesame seeds grown in Uganda is largely unkown. Seed health test of 30 seed samples from different parts of Uganda revealed the presence of 12 fungal species, namely, Acremonium sp., Alternaria sesami,A. sesamicola, Bipolaris sp. Cercospora sesami, Corynespora cassiicola, Fusarium equiseti, F. moniliforme, F. pallidoroseum, Macrophomina phaseolina, Myrothesium roridum and Phoma sp. High incidence, 0.3 - 68% of A. sesamicola and 0.3 - 29% of C. sesami were recorded in 29 and 30 seed samples, respectively. The rest of the pathogens occurred in moderate levels, 0.3 - 5% for Acremonium sp., Corynespora cassiicola, A. sesami, F. equiseti, M. phaseolina, F. pallidoroseum, F. moniliforme and Phoma sp. and in trace amounts, 0 - 0.3% for Bipolaris sp. and M. roridum. These pathogens caused seed rot, poor germination and seedling mortality. Two control measures; sorting by salt solution and seed-treatment with Dithane M-45 were used to separate healthy seeds from diseased ones, and kill seed-borne fungi, respectively. Both sunken and floated seeds had infected and healthy seeds in the samples tested indicating the use of salt solution, was not effective for obtaining healthy seeds in sesame. Seed treatment with Dithane M-45 killed all the mycoflora except A. sesamicola which was detected in 4 out of 14 samples but with a reduced incidence of 0 - 0.5% as opposed to 0-66% in the control. Thus, seed-dressing with Dithane M-45 is recommended for control of sesame seed-borne pathogens.
Efficacies and profitability of different fungicides and spray regimes for control of soybean rust (Phakopsora pachyrhizi Syd.) in Uganda
Three fungicides: Dithane- M45 (contact wettable powder), Saprol and Folicur (both systemic), and three spray regimes, weekly. 2-weekly, and 3-weekly sprays from disease onset to full seed formation, were evaluated against soybean rust incited by Phakopsora pachyrhizi Syd. These corresponded to 5, 3, and 2 sprays, respectively. Nam 2 a highly susceptible variety was used in the study. The unprotected soybean had significantly higher rust severities (>75%) and lower yields (968 kg/ha) as compared to the rust-protected soybean, with rust severities < 70%) and yields (> 1000 kg/ha). Highest yield increase with Dithane, Saprol, and Folicur of 26.9, 33.3 and 38.9%, respectively were obtained under the weekly, 2-weekly, and 3-weekly spray schedules. The highest economic returns for Dithane (71, 252 Shs/ha), Saprol (127,607 Shs/ha), and Folicur (236, 181 Shs/ha), were obtained under the 2-weekly, 2-weekly, and 3-weekly spray schedules. Rust control was associated with increased seed weight and number of filled pods per plant.
Potential of intercropping napier grass with maize during the establishment phase of napier grass
Napier grass (Pennisetum purpureum) serves a variety of functions, which include provision of fodder. However, small scale farmers in East Africa need both food and fooder crops. Hence, research to determne the potential of intercropping napier with maize (Zea mays) is relevant. This was done using a range of spatial arrangements. In a relatively drought season (1999b), when measurements were limited to the rows closest to napier-in order to determine its competition on maize, double napier rows alternating with single maize rows resulted in 55-68% reduction in maize dry matter (DM) production. The reduction in DM production was only 14% for the additive mixture. The reduction in napier biomass yield for the row closest to maize row(s) was significantly greater, 67-73%, in mixures in which 2 maize rows alternated with single napier grass rows. In a better growing season (2000a), maize DM production during the grain filling period was 19-76% lower in mixtures (depending on spatial row arrangement) compared to the pure stands, and the additive mixture did not exhibit reduction in maize DM production until the dough stage. Maize grain yield and yield components in the additive mixture and the 1:3 napier:maize row arrangement were not significantly lower than the sole maize, and maize was the dominant species in the mixtures. It was concluded that during the first phase of napier growth (before regular cutting back for fodder commences) it is possible to superimpose a maize row between the pure stand napier without much reduction in maize yield (only 5%). The reduction in maize yield in the 1:3 napier: maize rows arrangement was also negligible (6%). However, zero-grazing farmers who are more interested in napier biomass and a bonus of maize yield would take the 3:1 row arrangement. The higher maize yield for the additive mixture and the 1:3 mixture compared to the others, during the first phase of napier growth, was attributed to the higher population of maize plants in these mixtures. However, maize in these mixtures was competitive against the young napier plants and reduced its biomass production.
Development of gray leaf spot from inoculated foci on two maize cultivars in Uganda
The spatio-temporal spread of gray leaf spot on maize caused by Cercospora zeae-maydis was studied in two locations in central Uganda. Gray leaf spot development was assessed for three cropping seasons at 0.75 m to 5.25 m from inoculated foci on two open-pollinated maize varieties. In all the seasons, disease spread was adequately depicted by both power and exponential models. Distance from inoculum focus significantly (P<0.05) affected leaf damage but the effect of direction from inoculated focus was variable depending on the season, location and cultivar. Thus, depending on the location and seasonal variation, genotype effect greatly affects severity of gray leaf spot. Gradients for the two cultivars differed significantly (P<0.001) in intercept (a) but not slope (b) of the linearised power disease gradient for the number of lesion on the ear leaf. Our results indicate that maize genotypes affect both increase and spread of gray leaf spot. The rapid flattening of the disease gradient was indicative of long distance dispersal of C. zeae-maydis in tropical unlike in temperate environments.
The effects of inter-cropping maize with beans on maize diseases infestation
A study was carried out to assess the effects of inter-cropping maize with beans on maize diseases infestation Eight diseases were recorded to affect maize with maize streak virus, northern leaf blight (Exserohilum turcicum), gray leaf spot (Cercospora zeae-maydis), and Sternocarpella macrospora leaf blight (Sternocarpella macrospora), being most prevalent. Disease incidence ranged between 0% for sorghum downy mildew (Peronosclerospora sorghi) to 80% for gray leaf spot. Gray leaf spot was the most common and was in some instances the most severe disease and attacked all varieties irrespective of the cropping system. Despite the high severity scores however, gray leaf spot disease did not affect maize yield. Other diseases also developed irrespective of whether the maize was sole or inter-cropped thus, resulting in no significant difference in disease reaction between mono or intercropped maize. In this particular study, intercropping maize with beans was not found to reduce maize streak virus disease incidence and severity as reported in earlier studies. These variable findings underscore the need for further work on disease incidence and development under mixed cropping systems.
Nutritional evaluation of elephant grass hybrids
The nutritive value with regard to stage of maturity of elephant grass (Pennisetum purpureum) hybrids is largely unknown. Elephant grass (KW,) and its hybrids namely, ILCA16786, ILCA16837, ILCA16791.and ILCA16798 were evaluated to determine the effect of stage of maturity on dry matter yields (DM), chemical composition, intake and digestibility by sheep. In the first experiment, forages were harvested at 6, 7, 8, 9,10, 11 and 12 weeks of re-growth. With advancing maturity, DM yields and the fibrous fractions increased while crude protein (CP) and in vitro DM digestibility (IVDMD) decreased. In the second experiment, the re-growths at 6 weeks were fed to sheep in form of hay. Apart from ILCA16837, the rest of the forages had similar DM intakes (P>0.05). For ILCA16798 a higher (P<0.05) DM digestibility was observed compared to the other hybrids but ILCA16791, ILCA 16786 and KW, did not show any significant difference while ILCA16837 had the lowest (P>0.01) DM digestibility. Digestibility of CP was similar for KW, LCA16791 and ICAl6837 but was significantly different (P<0.05) from ILCA 16798 and ILCA16786. Hybrid ILCA 16791, had the highest NDF and ADF digestibilities followed by ILCA16786 and ILCA 16837 while KW, and ILCA 16798 had the lowest. The differences in DM intake and digestibilities might have been influenced by the genetic makeup of the individual hybrids.
Copyright (c) 2001 https://creativecommons.org/licenses/by-nc-nd/4.0
Nutritive value of selected forages on the coastal region rangelands of Tanzania
Although the nutritive value of forage species is of paramount importance to livestock production, it is largely unknown for most rangelands of East Africa. A study was carried out on a rangeland area west of the Ruvu floodplains, Bagamoyo district, coastal Tanzania to determine the nutritive value of palatable herbaceous species. The commonly occurring palatable grasses (at their flowering stage) and browse species were analysed for crude protein (CP), crude fibre (CF) and major mineral elements (calcium, magnesium and phosphorus). The forage species analysed were Urochloa mosambicensis, Panicum maximum, Panicum parvifolium, Eragrostis superba, Sporobolus pyramidalis (grasses), Commiphora africana and Pteleopsis myrtifolia (browse). The species had adequate levels of crude protein (grass: 8.65₺2.15%; browse: 13.61+2.26%), crude fibre (grass: 35.98+5.15%; browse: 19.17+3.64%), phosphorous (grass: 0.2310.13%; browse: 0.18t0.01%), calcium (grass: 0.25+0.10%; browse: 0.4910.11%), Ca:P ratio (grass; 1.0:1.0 - 5.6:1.0; browse: 1.79:1.0 - 3.68:1.0), and magnesium ( grass: 0.3610.11%; browse: 0.33+0.01%) to support the growth and maintenance of livestock. Their CP, CF and mineral contents were significantly different, with browse having highest nutritive value. P. maximum, P. parvifolium, Urochloa mosambicensis, Sporobolus pyramidalis, and E. superba were significantly different in their %CP (P<0.001), %CF (P<0.0001), Ca (P<0.05), and P (P<0.05) contents. There was a significant negative correlation between %CF and phosphorus, calcium, and %CP; and between magnesium and %CP. Significant positive correlations occurred between %CP and phosphorus; and %CP and calcium. Implications of these results tor rangeland utilisation for animal production and management are discussed.
Variation in plasma luteinising hormone levels, return to ostrus and ovulation rates in sows on different planes of sorghum based rations
Twenty one gilts were fed two levels of lactation rations nested within two levels of gestation rations to evaluate the effect of level of feeding on reproductive parameters. Twelve sows were given each of two levels of feeding (High (H) and low (L)) during gestation. The H-sows were subdivided into two groups one of which received the high level (HH) while the other received the low level of feeding (HL). The L sows were similarly subdivided to form 2 groups of sows, the first of which received the level (LH) while the other received the low level (LL) of feeding, respectively. Production of porcine luteinising hormone (pLH) during lactation, and ovulation parameters, in the subsequent gestation, was assessed. Sows fed high (H) had significantly better (P<0.05) ovulation parameters than the low fed sows (L). The ovulation for high fed and low fed sows were 14.2 and 13.6 ova released, the ovary weights were 7.4g and 6g for high fed and low fed sows, respectively. However, gestation level of feeding did not influence the size of the corpora lutea. Lactation level of feeding had a significant (P<0.05) effect on ovulation (7.2 and 6.4 ova) and corpora lutea size (0.49g and 0.56g). Subsequent ovary size was not affected by level of feeding during lactation. There was an interaction between level of feeding during gestation and that during lactation with sows changing from high to low performing poorest among all the four feeding levels. Overall the previous gestation's level of feeding had an over-riding effect on these parameters mediated by its effect on plasma levels of pLH in the previous lactation. Based on results obtained its concluded that level of feeding during gestation was more likely to influence subsequent sow reproductive performance by specifically affecting ovary function as well as early embryo development.
Chemical composition and feeding value of some Sorghum Cultivars Grown in Uganda
Characterisation of meat goat management systems
A survey of goat production farms was carried out using a structured questionnaire in 70 randomly selected households in Kiboga, Mpigi and Sembabule districts of central Uganda. The objective of the study was to determine the goat production systems and their characteristics. Indigenous goats of the Mubende and Small East African breeds and their crosses are reared. In Mpigi Mubende-boer crossbreds are also reared. Goats are kept for cash from direct sale and slaughter for festivities. Gifts, manure production and dowry were also mentioned among the purposes for which goats are reared. Herds are housed in roofed shelters, kitchens, and on verandas. Tethering was the predominant feeding system followed by open grazing and zero grazing. The average herd size was between 10 and 30 goats. Most farmers provided salt and water though with no clear routine, while a few farmers supplemented feeding with crop resides and tree fodder. The average age of does at first service was 11, 9 and 11.5 months in Kiboga, Mpigi and Sembabule respectively, while the mean kidding intervals for the respective districts were 9, 7 and 9 months.
Response to phenotypic screening of Mubende meat goats
Sixty-two mature goats of the Mubende breed sampled from the field on the basis of heart girth were used in a study to estimate the contribution of parental phenotype to body weight gain at different ages in indigenous goats. Four mating groups were formulated on the basis of weight and heart girth of the does and bucks. At birth, kids from the elite mating group were heavier (P<0.05) than those of the controls. Kids born to elite bucks though not significantly heavier from kids born to ordinary ones at birth, were progressively heavier with time, 8 weeks (P<0.01), weaning (P<0.01) and at one year (P<0.05). Average kid birth weights were 2.34, 2.12, 2.28, 2.11 kg for elite, reciprocal 1, reciprocal I and control, respectively. Male kids were significantly heavier (P<0.001) at birth and all subsequent ages up to 40 weeks, and showed a faster growth rate (P<0.01) to 52 weeks of age, than female kids. Kids from single birth weighed an average of 2.29 kg at birth compared to 2.05 kg for kids born as twins. The differences in birth weight were significant (P<0.001) and persisted up to 44 weeks of age. Post weaning kid diet had a significant influence on body weight gain with animals weaned on a diet of 25% crude protein (P) gaining at a faster rate than those fed a 15% CP diet.
Suckling practices and calf performance under intensive smallholder dairy production system in a high potential lowland area in Tanzania
In Tanzania, farmers use different calf rearing practices but the most appropriate practice remains largely unknown. The study was done at Turiani Division - Morogoro rural district to evaluate calf rearing practiced by the smallholder dairy farmers in 7 villages. Data on milk production, growth performance of calves and mortalities indicate a high degree of adoption of standard management practices and keenness of the farmers on this activity. The study showed that, three calf rearing practices were undertaken by the farmers. The first practice was that of allowing a calf to suckle a dam before and after milking. The second practice was that of reserving one teat for a calf to suckle, and the third one was that of reserving two teats for a calf to suckle. These calf rearing practices and sexes were correlated with calf daily gain and weaning weights. No significant differences were shown between female calves suckled one or two teats in terms of daily gains and weaning weights. However, there were significant differences between female calves allowed to suckle one teat and the rest of categories with respect to daily gains and weaning weights. However, since most of the calves were males, this observation may have been contributed by differential treatment by the farmers. The trend of performance by individual groups of calves in different calf rearing practices was the same for both weaning weight and daily gain, indicating that daily gain and weaning weight are correlated positively. However, female calves were much favoured by the practice of reserving one teat for calf suckling but were severely affected by the practice of suckling before and after milking. From this study, it has been shown that, reserving one teat for a calf to suckle was the best practice.
Nutritional effects on growth and carcass characteristics of Ankole, Nganda and Ankole x friesian crossbred bulls
The study investigated the effect of protein supplementation on growth and carcass characteristics of grazing Ankole, Ankole x Friesian and Nganda bulls. Seventy two bull calves, 24 of each breed-type were randomly assigned to one of the three dietary treatments; the control of grazing alone (GZ), grazing followed by a 17.6% crude protein (CP) supplement (GZ + MD) and grazing followed by a 19.4% CP supplement (GZ + HG). The bulls were weighed fortnightly, and at the end of the feeding period all the bulls were slaughtered. Before slaughter, the live weight of each animal was taken, carcasses weighed hot, scored for grade and their dressing percentages determined. No significant (> 0.05) breed-type effects were observed in average daily gain (ADG). Significant variation (P <0.05) attributable to diet in ADG was observed. The supplementary diets (GZ+ MD and GZ+ HG) produced higher (P < 0.05) ADGs than the grazing alone diet. However, there were no significant (P>0.05) differences observed between the two supplementary diets. Significant variation (P <0.05) attributable to diet and breed-type in hot carcass weight, carcass grade and dressing percentage was observed. The (GZ + HG) bulls exhibited the highest (P < 0.05) dressing percentages, heaviest (P < 0.05) hot carcass weights and the highest (P < 0.05) carcass grades. The grazing alone diet averaged poorest and was significantly different (P < 0.05) from all the carcass measurements. Under the (GZ + HG) diet, the Ankole bulls possessed the highest (P <0.05) carcass grades and the heaviest (P < 0.05) hot carcass weights.