Potential of cowpea, pigeonpea and greengram to supply mineral N to maize in rotation on ferralsols in Muheza Tanga- Tanzania

Tanzania Journal of Agricultural Sciences, 2008; 9 (1) : 1- 8A rotational field experiment of cowpea, pigeonpea and greengram with maize as married out for two rotational cycles to determine the potential of the legumes to supply N to the subsequent maize. The experiment was carried out on sandy clay Rhodic Ferralsol with bimodal rainfall pattern. The legumes were planted during the short rain season followed by maize during long rains. Soil was sampled from 0 - 20 em layer before maize planting from plots where the legumes were grown and from continuous maize plots. The composite soil samples were sieved through 6 mm screen while fresh. Sub samples equivalent to 250 g each were incubated in 500 ml wide mouth volumetric flasks at 60% field capacity and room temperature for 42 days. Destructive samplings were done at 14 days intervals and analysed for mineral N (NH4+ and N03-). The quantities of mineral N increased with incubation time. Most of the mineral N was mineralised between 0 and 14 days of incubation. Out of the total N mineralized during the entire incubation period, the proportions of the mineral N determined at the 14th day sampling were 64% for the cowpea, 50% for the pigeonpea, 73% for the greengram and 88% for the continuous maize plots. Such high proportions indicate that the subsequent maize would obtain maximum N during these early stages of growth. It was concluded that there is lack of synchrony between the release of mineral N and the maize crops' N demand which lead to the maize N deficiency symptoms and low yields observed in the legume - maize_cropping system

Contribution of legume rotations to the nitrogen requirements of a subsequent maize crop on a rhodic ferralsol in Tanga, Tanzania

Tanzania Journal of Agricultural Sciences 2013, Vol. 12(1) : 23-29Industrial fertilizers are expensive for small-scale farmers who, as alternative, rely on legume crops for providing N for a subsequent maize crop. A legume-maize rotational experiment was carried out on a Rhodic Ferralsol at Mlingano Agricultural Research Institute in Muheza, Tanga, Tanzania, to evaluate the effects of legumes rotation in meeting the N fertilizer requirements of maize. The experimental site was located at 39o 52’E, 5o 10’S and 183 metres above sea level (m.a.s.l.). The experiment was conducted for two rotation cycles whereby cowpea, pigeonpea or greengram were grown during the short rains followed by maize during the long rains. The maize rotations were imposed on plots on which legumes had been grown during the previous legume rotation. Monoculture maize was grown with treatments of 0, 25, 50 and 100 kg N ha-1 imposed for purposes of plotting N fertilizer response curves. Based on the response curve lines, the effects of the legume rotation on maize yields were compared and translated as N fertilizer equivalency of the legumes in question. The grain and residue yields of the three legumes were significantly different (P<0.01), a fact which was attributed to the genetic differences of the legume species. The maize yields following rotation with each of the three legumes were significantly higher (P<0.05) than those under continuous maize. The effects of the rotations on increasing the maize yields were equivalent to application of 25, 19 and 16 kg N ha-1 for the cowpea, pigeonpea and greengram rotations, respectively. It was, however, concluded that the contributions of N by the legumes in the legume-maize rotations were not enough to satisfy the maize N requirements of 50 kg N/ha; hence supplementation with mineral N, in addition to the rotations, is necessary for increased yields

Quantification of atmospheric n2 fixed by cowpea, pigeonpea and greengram grown on ferralsols in Muheza District, Tanzania

Tanzania Journal of Agricultural Sciences 2013, Vol. 10(1) : 29-37Legume crops are usually intercropped with cereals in small-scale farming systems in Tanzania. This aims at taking advantage of legumes to replenish soil nitrogen (N due to legumes’ N2 fixation). Glasshouse pot experiments and field trials were carried out atMlingano Agricultural Research Institute in Tanga, Tanzania, with the objective to find out how much N2 can be fixed by cowpea, pigeonpea and greengram using native Rhizobia, thus substituting for the use of N-mineral fertilizers in maize production on Ferralsols. In the glasshouse pot experiment, the legumes were grown in 5L plastic pots for 40 days in soil sampled from 0 – 20 cm layer. The field experiment was maize – legumes intercropping whereby the N2 fixation assessment was done 35 days after planting. In both cases, maize (Katumani variety) was the non- N2- fixing reference crop. The legumes formed effective nodules with the native Rhizobia. Different quantities of N2 gas were fixed by the different legumes, the differences being attributed to the legumes’ differences in their genetic characteristics. In the field, monocropped cowpea, pigeonpea and greengram fixed 38, 21, and 49 kg N2, respectively. In the intercrop system cowpea, pigeonpea and greengram fixed 16, 4, and 24 kg N2, respectively. In both cases, the quantities of N2 fixed were less than 50% of their total N accumulation. It was concluded that in Muheza, maize grown in association with the legumes would continue to need supplementation of mineral N fertilizer to maximize its yields

Contribution of legume rotations to the nitrogen requirements of a subsequent maize crop on a rhodic ferralsol in Tanga, Tanzania

Tanzania Journal of Agricultural Sciences 2013, Vol. 12(1) : 23-29Industrial fertilizers are expensive for small-scale farmers who, as alternative, rely on legume crops for providing N for a subsequent maize crop. A legume-maize rotational experiment was carried out on a Rhodic Ferralsol at Mlingano Agricultural Research Institute in Muheza, Tanga, Tanzania, to evaluate the effects of legumes rotation in meeting the N fertilizer requirements of maize. The experimental site was located at 39o 52’E, 5o 10’S and 183 metres above sea level (m.a.s.l.). The experiment was conducted for two rotation cycles whereby cowpea, pigeonpea or greengram were grown during the short rains followed by maize during the long rains. The maize rotations were imposed on plots on which legumes had been grown during the previous legume rotation. Monoculture maize was grown with treatments of 0, 25, 50 and 100 kg N ha-1 imposed for purposes of plotting N fertilizer response curves. Based on the response curve lines, the effects of the legume rotation on maize yields were compared and translated as N fertilizer equivalency of the legumes in question. The grain and residue yields of the three legumes were significantly different (P<0.01), a fact which was attributed to the genetic differences of the legume species. The maize yields following rotation with each of the three legumes were significantly higher (P<0.05) than those under continuous maize. The effects of the rotations on increasing the maize yields were equivalent to application of 25, 19 and 16 kg N ha-1 for the cowpea, pigeonpea and greengram rotations, respectively. It was, however, concluded that the contributions of N by the legumes in the legume-maize rotations were not enough to satisfy the maize N requirements of 50 kg N/ha; hence supplementation with mineral N, in addition to the rotations, is necessary for increased yields

Cyanobacterial toxins and bacterial infections are the possible causes of mass mortality of lesser flamingos in Soda lakes in northern Tanzania

Research Opinions in Animal and Veterinary Sciences 2013, Vol. 3(x) xxxDuring the mass die-off of lesser flamingos in Soda lakes of Tanzania in 2000, 2002 and 2004, clinicopathological and toxicological investigations were made in order to elucidate the likely cause of mortality. Water and tissue samples were collected from the lakes and from dead flamingos respectively. While water samples were analyzed for pesticide residues, tissues were analyzed for pesticide residues and cyanotoxins. The significant pathological lesions observed in fresh carcasses included oedema in lungs, enlarged liver, haemorrhages in liver with multiple necrotic foci, haemorrhages in kidneys and haemorrhages in intestines with erosion of mucosa. Analysis of cyanotoxins revealed presence of neurotoxin (anatoxin-a) and hepatotoxins (microcystins LR, RR). Concentrations of microcystins LR were significantly higher (P = 0.0003) in liver than in other tissues. Based on clinicopathological findings and concentrations of the detected cyanotoxins, it is suspected that cyanobacterial toxins concurrent with secondary bacterial infection were the likely cause of the observed mortalities in flamingos

Cyanobacterial toxins and bacterial infections are the possible causes of mass mortality of lesser flamingos in Soda lakes in northern Tanzania

Research Opinions in Animal and Veterinary Sciences 2013, Vol. 3(x) xxxDuring the mass die-off of lesser flamingos in Soda lakes of Tanzania in 2000, 2002 and 2004, clinicopathological and toxicological investigations were made in order to elucidate the likely cause of mortality. Water and tissue samples were collected from the lakes and from dead flamingos respectively. While water samples were analyzed for pesticide residues, tissues were analyzed for pesticide residues and cyanotoxins. The significant pathological lesions observed in fresh carcasses included oedema in lungs, enlarged liver, haemorrhages in liver with multiple necrotic foci, haemorrhages in kidneys and haemorrhages in intestines with erosion of mucosa. Analysis of cyanotoxins revealed presence of neurotoxin (anatoxin-a) and hepatotoxins (microcystins LR, RR). Concentrations of microcystins LR were significantly higher (P = 0.0003) in liver than in other tissues. Based on clinicopathological findings and concentrations of the detected cyanotoxins, it is suspected that cyanobacterial toxins concurrent with secondary bacterial infection were the likely cause of the observed mortalities in flamingos

Using fuzzy cognitive mapping as a participatory approach to analyze change, preferred states, and perceived resilience of social-ecological systems

There is a growing interest in the use of fuzzy cognitive mapping (FCM) as a participatory method for understanding social-ecological systems (SESs). In recent years, FCM has been used in a diverse set of contexts ranging from fisheries management to agricultural development, in an effort to generate transparent graphical models of complex systems that are useful for decision making, illuminate the core presumptions of environmental stakeholders, and structure environmental problems for scenario development. This increase in popularity is because of FCM's bottom-up approach and its ability to incorporate a range of individual, community-level, and expert knowledge into an accessible and standardized format. Although there has been an increase in the use of FCM as an environmental planning and learning tool, limited progress has been made with regard to the method's relationship to existing resilience frameworks and how the use of FCM compares with other participatory modeling/approaches available. Using case study data developed from community-driven models of the bushmeat trade in Tanzania, we examine the usefulness of FCM for promoting resilience analysis among stakeholders in terms of identifying key state variables that comprise an SES, evaluating alternative SES equilibrium states, and defining desirable or undesirable state outcomes through scenario analysis

Confidence in COVID-19 vaccine effectiveness and safety and its effect on vaccine uptake in Tanzania : A community-based cross-sectional study

COVID-19 is a major public health threat associated with increased disease burden, mortality, and economic loss to countries and communities. Safe and efficacious COVID-19 vaccines are key in halting and reversing the pandemic. Low confidence in vaccines has been one of the factors leading to hesitancy. We aimed to assess the COVID-19 vaccine confidence (safety and effectiveness), associated factors, and its effects on vaccine uptake among general community members in Tanzania. This was a community-based cross-sectional survey conducted from December 2021 to April 2022 in six regions of Tanzania mainland and two regions in Zanzibar. Participants were interviewed using an electronic questionnaire. Multiple logistic regression models estimated odds ratios (ORs) and 95% confidence interval (CI) for factors associated with vaccine confidence. All analyses were performed using SPSS version 25.0. The study enrolled 3470 general Tanzanian community members; their mean age was 40.3 (standard deviation ±14.9) years, and 34% were males. The proportion of COVID-19 vaccine confidence was 54.6%. Geographical region, residence area, COVID-19 disease risk perception, and good knowledge of COVID-19 vaccines were significantly associated with COVID-19 vaccine confidence. Confidence in COVID-19 vaccines was associated with over three times higher odds of vaccine uptake. Confidence in COVID-19 vaccines was low in Tanzania. Innovative community engagement strategies and region-specific interventions are needed to improve comprehensive knowledge and address community perceptions and attitudes toward COVID-19 vaccines

A Qualitative Study on Barriers to COVID-19 Vaccine Uptake among Community Members in Tanzania

The use of vaccines is one of the key tools in reversing the COVID-19 pandemic; however, various reports reported the low uptake of the vaccines. This study explored the barriers to the COVID-19 vaccine uptake among community members in Tanzania. A qualitative explorative study was conducted in December 2021 and April 2022 in eight regions of Tanzania. Focus group discussions (FGDs) and in-depth interviews (IDIs) were the methods of data collection. A total of 48 FGDs and 32 IDIs were conducted. Participants were aware of the COVID-19 disease and vaccines. The barriers to the COVID-19 vaccine non-uptake included receiving contradicting statements from top government leaders, vaccine preceded the education, myths towards vaccines, the presence of different types of vaccines, the process of getting the vaccine, the influence of social media and random people from the community, and vaccine conflicting religious beliefs. Despite being aware of the vaccine, the uptake of the COVID-19 vaccine is still low. Interventions that focus on increasing community knowledge about COVID-19 vaccines and addressing myths about the vaccines are needed