Tanzania Journal of Agricultural Sciences

Influence of Bio-rock P fertilizer on nutritional composition of whole maize grains: The case of Madaba and Morogoro, Tanzania

S. Pela — 2023-02-11

This study was designed to understand the influence of Bio-rock P fertilizer as the source of phosphorous on nutritional composition in maize grain. Bio-rock P fertilizer is a preparation made of rock phosphate and phosphate solubilizing bacteria (PSB). The experiment was laid out in randomized complete block design with three replications each receiving five rates of bio-rock phosphate fertilizer (Control, 20 kg P/ha with PSB, 40 kg P/ha with PSB, 60 kg P/ha with PSB and 80 kg P/ha with PSB). The study was carried out at two geographically different sites; Magadu in Morogoro and Madaba in Ruvuma for the duration of 90 days in the 2019 - 2021 cropping season. In both sites, the results showed that, bio-rock phosphate fertilizer rates had no significant influence on percentage protein, carbohydrate, fibre and moisture content. However, Bio-rock P rates had a significant effect on ash and fat contents of maize grains (p<0.05). Bio-rock phosphate fertilizer rates had no significant influence on percentage protein, carbohydrate, fibre and moisture content. For mineral content, there was significant difference in P, K, Mg, and Fe in Magadu and Madaba samples. Therefore, application of bio-rock phosphate increased macronutrients content (ash and fat) and some of micronutrients specifically phosphorous, potassium, magnesium and iron content and as the rates of bio-rock phosphate increased.

Growth and yield of three Brachiaria cultivars from the Southern Highlands, Rungwe, Mbeya, Tanzania

I.S. Selemani — 2023-02-11

Scarcity of grazing land in the Southern Highlands of Tanzania limits livestock production. Although high yielding pasture species such as Brachiaria are recommended in the areas where land is limiting factor, there is limited information on its growth and yield under humid climates. The experiments were conducted in Rungwe district to test performance of three cultivars of Brachiaria (Brachiaria brizantha cv. piata, Brachiaria brizantha cv. xaraes and Brachiaria decumbens cv. basilisk) against the local pasture species, Pennisetum purpureum. The study used the Complete Randomized Block Design where two experiments (on-station and on-farm) were considered as blocks, while Brachiaria cultivars were treated as main factors. Data on germination characteristics were recorded during the first two weeks after sowing whereas data on growth performance were collected at intervals of four weeks for three months consecutively. Farmers’ performance evaluation and above ground biomass estimation was done at week 13rd of the experiment. Although, Pennisetum purpureum was consistently ranked higher by farmers in terms of growth attributes, the field data established little variations with other Brachiaria cultivars. Interestingly, B. decumbens cv. basilisk scored relatively higher values for germination rate, tiller number and biomass which imply its good growth and productive performance. The lower mean height of B. decumbens cv. basilisk probably optimises the accumulation of its biomass. The B. brizantha cv. xaraes exhibited lowest growth performance, and was relatively affected by insect and diseases. Therefore, the study recommended up-scaling of B. decumbens cv Basilisk in the Southern highlands and other areas with similar humid climate.

Contribution of Malawi’s decentralized agricultural extension service system to farmers’ maize productivity

P.J. Mphepo — 2023-02-11

Agricultural extension plays a critical role in the agricultural sector’s development and sustainability of farmers’ productivity and well-being. Malawi has consistently been reforming its agricultural extension services to increase accessibility by farmers. However, smallholder farmers’ productivity remains low. Therefore, the study on which the paper is based, aimed at examining the contribution of Malawi’s decentralized agricultural extension system (DAESS) to households’ maize productivity. Specifically, the study aimed at determining how farmers’ access to agricultural extension services, factors associated with their maize productivity and lastly, farmers’ satisfaction with Malawi’s DAESS. The study adopted the cross-sectional research design whereby a structured questionnaire was used to collect quantitative data from 150 smallholder maize farmers in Mangochi district, Malawi. In addition, supplementary data were collected from 10 focus group discussions involving 6 – 8 participants and from nine (9) key informant interviews. IBM-SPPS was used to determine descriptive and inferential statistics. Regression analysis was run to determine how access to extension services is associated with maize productivity. Farmers’ satisfaction with DAESS was measured using a 5-point Likert scale. Study findings show that farmers’ access to extension services was positively and significantly (p<0.001) associated with maize productivity and that 73.3% of smallholder farmers expressed a high level of satisfaction with the services provided. It is concluded that access and number of visits to extension services raise farmers’ maize productivity. It is also concluded that most smallholder farmers in Mangochi district were satisfied with the extension services they received. Therefore, it is recommended that the government of Malawi should continue with the implementation and improvement of the DAESS and use of the lead farmer approach to expand access to quality agricultural extension services by smallholder farmers.

Pathogenicity of Pyricularia oryzae isolates obtained from cultivars grown in middle and high altitudes zones of Burundi

E. Niyonkuru — 2023-02-11

Rice blast disease caused by the fungal pathogen called Pyricularia oryzae is an economically important disease distributed in rice-growing regions of the world. Understanding pathogenic variation among isolates paves a way towards the most effective ways to manage the disease. Thirteen isolates of P. oryzae from high and middle altitude rice ecosystems were inoculated into ten (10) cultivars most preferred by rice farmers in the middle and high-altitude areas of Burundi. The isolates were then evaluated for their ability to cause rice blast disease under screen house condition. A complete randomized design (CRD) with three replications was used. The tested cultivars were evaluated as susceptible(S) or resistant (R) to a particular P. oryzae isolate based on disease severity score determined through visual observation using a standard 0-9 scale developed by IRRI. Highly significant differences (p=0.000) between location were observed in rice blast disease incidence and severity. Significant differences (p=0.000) in blast incidence and severity were recorded between cultivars as well as isolate. Disease incidence and severity in the cultivars ranged from 11.11-33.33% and 3.70-69.14% respectively. Despite this variability in the isolate pathogenicity, three rice cultivars (Mugwiza, Rufutamadeni and V18) were less susceptible to the disease and hence can be regarded as having traits of resistance which can be used by rice farmers for managing rice blast disease in the two rice ecosystems of Burundi but also as parent materials for development of rice cultivars with resistance to rice blast.

Production of freshwater infusoria and Blacksoldier fly larvae using various organic substrates as starter feeds for fish larvae

A.W. Mwandya — 2023-02-11

Freshwater infusoria were raised on banana peels, potato peels, cabbage leaves and water lettuce for three weeks while Blacksoldier fry larvae (BSFL) raised on goat, pig and cow dung manures for four weeks was later fed to juvenile Nile tilapia as started feeds. Infusoria and BSFL were cultured in twelve plastic containers each 40 liter and nine plastic plates each 0.135 m2 respectively. The density and biomass of infusoria; and water quality parameters were measured. The biomass and abundance of BSFL were determined. The growth performance and survival rates of Nile Tilapia (Oreochromis niloticus) were studied at three inclusion levels of BSFL (25, 75 and 100%) and fed twice a day in twelve polyethene tanks 20 litre each for two months. The mean density and biomass of infusoria were higher in banana peels and lowest in water lettuce leaves, at water temperature ranging from 21.5 ± 0.3 to 22.5 ± 0.5°C. Turbidity was generally highest in Lettuce leaves and lowest in Banana peels. Freshwater infusoria were active within 15 days of the experiment and became inactive with increasing turbidity. The biomass and abundance of BSFL were higher in pig manure and lowest in goat manure, and showed significant differences among inclusion levels (p<0.05). The growth rate of juvenile tilapia was numerically higher in treatment receiving 100% of BSFL (6.63±1.67 g) and lowest at 25% (1.92±31.11g) of BSFL. Results suggest potential of banana peels and pig manure as good substrate and higher inclusion level of BSFL to grow Nile tilapia.

Effects of contrasting agricultural land-use systems on selected soil properties in South-West Nigeria

A.K. Shittu — 2023-02-11

Conversion of natural ecosystems to managed ecosystems may have negative consequences on soil quality. A study was carried out in order to investigate the effects of various land-use systems on changes in selected soils properties in Derived savannah and Rain forest ecosystems in southwest Nigeria. The three land uses selected from the two agro-ecological zones were: Cashew plantation, Arable soil, and Sugarcane plantation. Selected soil properties measured were: Saturated hydraulic conductivity, bulk density, particle size distribution organic carbon, total nitrogen and exchangeable cations. The data obtained were statistically analyzed using ANOVA. Findings revealed that average soil pH in the Rainforest agro-ecology was lower in value (4.62) compared with that of the Derived savanna (5.29). The C: N was significantly higher in Sugarcane plantation under the two agro-ecological zones with 9.83 and 13.66 for Derived savanna and Rain forest respectively while Arable soil with average of 6.05 for Derived savanna and 5.63 for Rain forest was the least among the land use considered. Sugarcane plantations with higher C: N ratios can minimize the rate of organic matter decomposition and best trap carbon in the region as a technique to mitigate climate change impact on the soil. The study revealed that land management that involves proper management of soil properties can promote sustainable environment for optimal crop production.

Effect of Gonadotropin-releasing hormone (GnRH) analogue on semen characteristics of three ecotypes of Tanzanian native chickens

J.D. Luvanga — 2023-02-11

The effect of hormone treatment on semen quality characteristics and reproductive performance in male animals has been studied extensively. However, limited information is available on effect of Gonadotropin releasing hormone (GnRH) treatment on semen characteristics in galliform species. The aim of this study was therefore to examine the effect of synthetic GnRH on semen characteristics in three ecotypes of Tanzanian native chickens. A total of thirty-six mature cockerels (Ching’wekwe, Morogoro-medium and Kuchi ecotypes) were used in this study. Thirty cockerels (ten from each ecotype) were intramuscularly injected with 10 mcg (0.2 mL) of GnRH (Factrel®) once a week for five consecutive weeks. Six cockerels (two from each ecotype) were used for control purposes and they were given 0.2 mL of normal saline solution. Semen was manually collected at weekly interval by abdominal massage technique immediately after last GnRH injection for five consecutive weeks. Results showed that respective semen quality characteristics including semen volume, sperm motility, sperm concentration, proportion of morphologically normal and live spermatozoa increased significantly (p<0.05) in the treatment group (0.55±0.02 mL, 80.02±0.30%, 4.80±0.14 × 10⁹ sperm cells/mL, 91.25±0.3%, 91.65±0.31%) when compared to the control group (0.48±0.02 mL, 74.90±0.76%, 4.04±0.18 × 109 sperm cells/mL, 87.58±0.43%, 89.05±0.55%). Variations in semen pH between treated and control group was not significant. In conclusion this study indicates that semen quality characteristics can be improved by administration of GnRH to cockerels for increased semen quality characteristics and therefore increasing productivity in the poultry industry.

Influence of social capital on adaptation to climate variability and vulnerability in farming households in Chamwino District, Tanzania

A.T. Tumaini — 2023-02-11

Adaptation to climate variability results from an interplay of livelihood capitals. These capitals (social, financial, physical, human and natural) prevail within climatic and non-climatic conditions. Vulnerability to climate variability intensifies when people are socially disadvantaged. The study assessed the influence of social capital on farming households’ adaptation to climate variability and vulnerability using two villages in Chamwino District, Dodoma Region. A cross-sectional research design was employed, whereby data was collected from 160 randomly selected households using a questionnaire. In addition, data was collected from 32 focus group participants and 5 key informants. Findings show that a farmer's adaptation strategy can influence the accumulation or depletion of capital to adapt to climate variability. In addition, poor farming households (23.12%) have limited livelihood capitals thus, creating adaptation failure and reliance on less paid agricultural adaptation-based contracts to adapt to climate variability. A chi-square test results show no association between poor households’ adaptation strategies and their income (p>0.05). Therefore, it is concluded that adaptation is not one size fits all; availability of livelihood capital within the household defines the context of adaptation. Therefore, it is recommended that to absorb the vulnerability in adaptation to climate variability, there should be an active and sustained engagement of public and private stakeholders with the local community in prioritizing the adaptation needs of all socio-economic groups to enable them adapt to climate variability.