Farmers’ Perceptions on Salinity Problems in Irrigated Fields in Kilosa District

Soil salinity contributes to one of the most serious ecological and environmental problems in most of the irrigation schemes in Tanzania. Understanding farmers’ perceptions of soil salinity and its effects on crop productivity is important in promoting soil and water conservation practices. A study was conducted in Chanzuru and Ilonga villages in Kilosa District in 2016 to determine farmers’ perceptions on soil salinity problems in the District. Therefore, a socio-economic survey was carried out on 60 respondents.  Data were collected using the semi-structured questionnaires. The data were analyzed using SPSS descriptive statistics and chi-square test. The finding of the study showed that farmers perceived salinity more on the basis of location than they did on the basis of socio-demographics.  The main causes of soil salinity as perceived by farmers were poor quality of irrigation water and poor drainage systems. Some socioeconomic and demographic characteristics that significantly influenced the farmers’ perceptions were sex and household size. The perceptions of farmers in the study area varied significantly from village to village, with their socio-demographic determinants. Farmers adapted the strategy of crop diversification and increase in farm size as a response to the problem of salinity occurring in their fields. Farmer perception on salinity should therefore be used as entry point by stakeholders to develop intervention programs that help to solve the problems occurring in the farmers’ fields. Key words: Salinity, farmers’ perception, problem confrontation index, crop diversification, irrigation water, scheme, sources of information, extension servic

EVALUATION OF THE RESPONSES OF EIGHT RICE (Oryza sativa, L.) GENOTYPES TO VARIOUS CONCENTRATIONS OF NaCl IN A CONTROLLED ENVIRONMENT

Salinity is an ever increasing problem that reduces rice yield in many rice fields around the world. Developing salt tolerant rice (Oryza sativa L.) genotype is one of the solutions to the problem of salinity. This experiment was carried out in the Department of Crop Science and Horticulture at SUA to assess the salinity tolerance of 8 rice genotypes at the seedling stage. Ion accumulation in plants and dry matter content along with molecular markers were used to evaluate the tolerance of each rice genotype. The genotypes were IRRI 112, IRRI 124, FL 478, IRRI 113, IR65912-4B-10-3, IRRI 128, NERICA-L-19 and SUAKOKO-10. In this experiment, the genotypes were exposed to three salinity levels in a randomized complete block design arranged in factorial with three replications. The salinity levels were 100 mM NaCl, 50 mM NaCl and 0 mM NaCl. The homogenous mixture of sand, farm yard manure and rice husk (ratio of 6:2:10 respectively) was used as the planting medium for all rice genotypes. The soil texture was sandy clay-loam. The growth of the genotypes, ion accumulation and dry matter contents were significantly (p ≤ 0.05) affected by increase in NaCl concentration. Two Saltol SSR markers (RM7075 and RM562) were used to determine the presence of salinity tolerance (saltol) gene in rice genotypes.  Based on the SSR markers, ion accumulation and dry weight of plants, two genotypes (IR65192-4B-10-3, and IRRI112) along with FL478 were selected as salt tolerant while two (IRRI-113 and IRRI-128) were moderately tolerant, and three (NERICA-19, SUAKOKO-10 and IRRI-124) were the most susceptible genotypes.  Therefore, two susceptible parents (NERICA-19 and SUAKOKO-10) were selected and two donor parents (FL478 and IR65192-4B-10-3) were selected. Keywords: salinity stress; NaCl concentration; genotypes; markers; seedling stage; Oryza sativa;

Green manure and inorganic fertiliser as management strategies for witchweed and upland rice

Weed infestation, especially the Witchweed (Striga asiatica) is a serious problem in fertility-depleted soils of Tanzania. The use of urea fertiliser is known to control weed but resource-poor farmers cannot afford thistechnology due to high costs involved. To alleviate the problem of Striga and soil fertility, green-manure applications could be an alternative strategy. Ths study was conducted to (a) evaluate the potential of green manure against Striga, and (b) determine the potential of inducing Striga suicidal germination by selected green manures. For the first part of the study, treatments included three green manure species, Crotolaria ochlroleuca G. (sunhemp), Mimosa invisa L.(Colla) and Cassia obtusifolia L.(Sicklepod) superimposed with three fertiliserrates 0, 25 and 50 kg N ha-1. The treatments were laid out in a randomised complete block design (RCBD). In the second study part, the 3 green manure species were evaluated for their potential to stimulate Striga seed germination in the laboratory and the field. Results showed that green manure applications significantly reduceStriga infestation, resulting in significant rice yield increases. Green manure exhibited potential to induce suicidal germination of Striga. Based on these findings, green manure  applications should be promoted especially among smallholder resource-poor farmers as a strategy for control of Striga infestation in rice fields. Additionally, croprotation using rice and C. ochlroleuca is the best option since it reduces Striga infestation and increases yield of rice

Grain Yield Performance of Biofortified Climbing Common Bean Genotypes (Phaseolus Vulgaris L.) Evaluated Across Different Agro-ecologies in Tanzania

Assessment study on yield performance and consumer preferences characteristics of iron and zinc fortified bean genotypes was conducted between 2014/15 and 2015/16 seasons at different agro-ecologies of Tanzania. The objective of the study was to improve nutrition and income of smallholder farmers through growing and selling of high yielding and iron bean genotypes. The experiments consisted of five high iron enhanced climbing common bean genotypes namely:  MAC 44 (80.3 mg/kg), RWV (78 mg/kg), MAC9 (64 mg/kg), MAC49 (66.6 mg/kg) and Selian (35.2 mg/kg). These planting materials were planted in Randomized Complete Block Design (RCBD) with three replications in Arusha at ARI-Selian farm, Lambo in Kilimanjaro, ARI-Uyole in Mbeya and in Kagera at ARI-Maruku. The sites ARI-Selian and Maruku represented mid altitude agro-ecologies, ARI Uyole (high altitude) and Lambo site is low agro-ecology. Grain yield and disease reaction scores data was collected and analysed using GenStat 15th edition software. Results showed significance difference (P≤0.05) for grain yield and diseases. Grain yield ranged from 1538kg/ha to 4314 kg/ha. Genotype RWV1129 produced 3091 kg/ha in 2014/2015 where as MACC44 yielded relatively higher (3530kg/ha than RWV1129 at Selian site in 2015/2016 season. The farmers’ participatory variety selection approach used in selecting of new improved bean genotypes depicted high yield, high market demanded, and resistant to diseases as the key important criteria. Genotypes MACC44 and RWV 1129 were the best genotypes accepted by farmers due to their high yield, and high market value.  Therefore, the study recommended them to be registered and released as nutritionally improved varieties for farmers’ cultivation and consumption thereby to relief the iron deficient vulnerable groups in Tanzania. Keywords: Climbing bean, Biofortification, Performance, Iron and Zinc DOI: 10.7176/JBAH/9-4-0

What incentives encourage local communities to collect and upload mosquito sound data by using smartphones? A mixed methods study in Tanzania

Background To detect and identify mosquitoes using their characteristic high-pitched sound, we have developed a smartphone application, known as the ‘HumBug sensor’, that records the acoustic signature of this sound, along with the time and location. This data is then sent remotely to a server where algorithms identify the species according to their distinctive acoustic signature. Whilst this system works well, a key question that remains is what mechanisms will lead to effective uptake and use of this mosquito survey tool? We addressed this question by working with local communities in rural Tanzania and providing three alternative incentives: money only, short message service (SMS) reminders and money, and SMS reminders only. We also had a control group with no incentive. Methods A multi-site, quantitative empirical study was conducted in four villages in Tanzania from April to August 2021. Consenting participants (n = 148) were recruited and placed into one of the three intervention arms: monetary incentives only; SMS reminders with monetary incentives; and SMS reminders only. There was also a control group (no intervention). To test effectiveness of the mechanisms, the number of audio uploads to the server of the four trial groups on their specific dates were compared. Qualitative focus group discussions and feedback surveys were also conducted to explore participants’ perspectives on their participation in the study and to capture their experiences of using the HumBug sensor. Results Qualitative data analysis revealed that for many participants (37 out of 81), the main motivation expressed was to learn more about the types of mosquitoes present in their houses. Results from the quantitative empirical study indicate that the participants in the ‘control’ group switched on their HumBug sensors more over the 14-week period (8 out of 14 weeks) when compared to those belonging to the ‘SMS reminders and monetary incentives’ trial group. These findings are statistically significant (p  0.95 under a two-sided z-test), revealing that the provision of monetary incentives and sending SMS reminders did not appear to encourage greater number of audio uploads when compared to the control. Conclusions Knowledge on the presence of harmful mosquitoes was the strongest motive for local communities to collect and upload mosquito sound data via the HumBug sensor in rural Tanzania. This finding suggests that most efforts should be made to improve flow of real-time information back to the communities on types and risks associated with mosquitoes present in their houses

“ Fighting against malaria is everyone’s concern”: a randomized control trial assessing the role of incentives for encouraging local communities to record and upload mosquito sounds using the MozzWear application

Background: Current malaria surveillance methods are considered too expensive to scale-up within limited-resource settings; hence, new technologies and approaches are necessary to maximize the collection of data and ultimately design new malaria control tools. Effective mosquito surveillance can be enhanced through the utilization of digital technologies and the engagement of citizens in real-time data collection. This study used the HumBug acoustic sensor with the MozzWear app to detect and identify host-seeking mosquitoes based on their flight sounds, with citizens receiving airtime incentives for recording and uploading sounds. Methods: A randomized controlled trial was used to assess the role of incentives to encourage the local community to record and upload mosquito sounds using the MozzWear application. Participants were randomized into two groups: (1) a control group, in which no incentive was provided; and (2) an incentive group, in which airtime credit was provided to participants. Both groups were provided with HumBug smartphones running the MozzWear app plus adapted mosquito bed nets (‘HumBug Nets’) to hold the phones during recording and were asked to record and upload mosquito flight tone data once per week for a period of four months. The intervention group was rewarded with an airtime incentive every week after the data were uploaded. At the end of the study, an experience survey was administered to participants in both groups to assess their experience participating in this study. Results: The overall results indicate that the control group performed well in terms of the number of nights spent recording and uploading data compared to the incentive group. The level of intrinsic and extrinsic motivation differs between demographic variables. Their feedback suggested that fighting against malaria was more important and was everyone’s concern in rural Tanzania. In addition, the participants expressed their interest in being involved in future research related to mosquito surveillance and the fight against malaria. Conclusion: Citizens can play a valuable role in scientific research; even without giving them incentives, they can still participate in the study. By participating in mosquito surveillance and malaria prevention studies, community members can make significant contributions to addressing mosquito-borne diseases and improving health outcomes

Climate, Vegetation, and Weathering across Space and Time in Lake Tanganyika (Tropical Eastern Africa)

Climate and vegetation influence weathering rates and processes; however, evaluating the effects of each and feedbacks between systems, has yet to be accomplished for many types of landscapes. A detailed understanding of how these processes interact to shape landscapes is particularly crucial for reconciling future scenarios of changing climate, where profound alterations to both the biosphere and geosphere are anticipated. In the tropics, ecosystem services, such as soil and water quality, are linked to both vegetation and weathering processes that form a strong control on natural resources that are the foundation of many communities’ daily subsistence. This understanding is further complicated by intensifying land-use within tropical watersheds, which decouples vegetation change from climate; it is yet unclear what the direct effects of vegetation change may be on erosion and weathering when operating independent of climate. Long term observational records tracking changes to the critical zone do not exist in tropical Africa, however, sedimentary paleo-records from lakes are often of sufficient length and resolution to record the impact of bioclimatic variability on surface processes. Here, we use a novel approach combining long (60ka) and intermediate-length (400yrs) lake sediment records along with historical repeat photography from Lake Tanganyika (Tanzania) to document changes and relationships among climate, vegetation, and weathering at multiple scales. These records illustrate that glacial-interglacial climate change did not significantly alter weathering intensity. Instead, we observe chemical and physical weathering responses only when the vegetation becomes more open beginning at the transition to the Holocene. Also, the largest change in chemical weathering intensity occurs only within the last ∼3ka. This is consistent with a major reorganization of vegetation and is directly attributable to Iron Age human activity, rather than climate. Furthermore, anthropogenic landscape alteration as early as ∼2.5ka, in addition to well-documented comparisons of historical land-use, suggest widespread responses of both chemical weathering intensity and enhanced soil erosion to human activity. This shows that changes in vegetation structure induced by anthropogenic activity, decoupled from climate change, generate a disproportionately large weathering response

Preferred resting surfaces of dominant malaria vectors inside different house types in rural south-eastern Tanzania

Background: Malaria control in Africa relies extensively on indoor residual spraying (IRS) and insecticide-treated nets (ITNs). IRS typically targets mosquitoes resting on walls, and in few cases, roofs and ceilings, using contact insecticides. Unfortunately, little attention is paid to where malaria vectors actually rest indoors, and how such knowledge could be used to improve IRS. This study investigated preferred resting surfaces of two major malaria vectors, Anopheles funestus and Anopheles arabiensis, inside four common house types in rural south-eastern Tanzania. Methods: The assessment was done inside 80 houses including: 20 with thatched roofs and mud walls, 20 with thatched roofs and un-plastered brick walls, 20 with metal roofs and un-plastered brick walls, and 20 with metal roofs and plastered brick walls, across four villages. In each house, resting mosquitoes were sampled in mornings (6 a.m.–8 a.m.), evenings (6 p.m.–8 p.m.) and at night (11 p.m.–12.00 a.m.) using Prokopack aspirators from multiple surfaces (walls, undersides of roofs, floors, furniture, utensils, clothing, curtains and bed nets). Results: Overall, only 26% of An. funestus and 18% of An. arabiensis were found on walls. In grass-thatched houses, 33–55% of An. funestus and 43–50% of An. arabiensis rested under roofs, while in metal-roofed houses, only 16–20% of An. funestus and 8–30% of An. arabiensis rested under roofs. Considering all data together, approximately 40% of mosquitoes rested on surfaces not typically targeted by IRS, i.e. floors, furniture, utensils, clothing and bed nets. These proportions were particularly high in metal-roofed houses (47–53% of An. funestus; 60–66% of An. arabiensis). Conclusion: While IRS typically uses contact insecticides to target adult mosquitoes on walls, and occasionally roofs and ceilings, significant proportions of vectors rest on surfaces not usually sprayed. This gap exceeds one-third of malaria mosquitoes in grass-thatched houses, and can reach two-thirds in metal-roofed houses. Where field operations exclude roofs during IRS, the gaps can be much greater. In conclusion, there is need for locally-obtained data on mosquito resting behaviours and how these influence the overall impact and costs of IRS. This study also emphasizes the need for alternative approaches, e.g. house screening, which broadly tackle mosquitoes beyond areas reachable by IRS and ITNs

Risk of Aedes-borne diseases in and around the Tanzanian seaport of Tanga despite community members being more concerned about malaria

Background Increased global trade, while beneficial economically, can also increase the spread of vector-borne diseases, particularly those transmitted by Aedes mosquitoes spreading via trade routes. Given the heightened trade-induced activity at ports of entry, it is particularly crucial to assess the risk of mosquito-borne diseases in these settings. This study compared the risks of Aedes-borne disease in and around the eastern Tanzanian seaport of Tanga. Methods A 200 m × 200 m grid-based system was used to sample mosquitoes within the port area, and in surrounding areas at 2 km, 2.5 km, and 5 km away, between June and December 2023. We characterized mosquito breeding habitats, collected mosquito larvae using standard dippers and tested susceptibility of raised adult Aedes aegypti populations to different insecticides. Adult mosquitoes were collected using BG sentinel traps (daytime) and Centers for Disease Control (CDC) light traps (night-time). Additionally, more than 200 port users and neighboring residents were surveyed to assess their experiences with and perceptions of mosquito biting and disease risks. Results There were 2931 breeding sites, with (60.8%, n = 1782) positive for Aedes larvae. The percentage of water-holding containers infested with Aedes immatures, i.e., the container index (CI), was highest in the port area (66.2%), and lowest 5 km away (44.6%). The port area also had a greater proportion of temporary breeding sites (64.9%) than did the surrounding areas. The adult mosquito surveys revealed 20,449 mosquito species including: Culex quinquefasciatus (56.2%), Mansonia uniformis (38.6%), Ae. aegypti (5.1%), Anopheles gambiae (0.1%), and Anopheles funestus. Ae. aegypti were more abundant in the port area than in the surrounding areas (P < 0.001), whereas Culex sp., and Mansonia sp., were significantly outside (P < 0.001). Adult Anopheles sp., were found only in the port area, but Anopheles larvae were found both within and outside the port areas. Tests on Ae. aegypti sp., revealed susceptibility to bendiocarb and DDT, and resistance to permethrin. Awareness of mosquito-borne diseases among respondents was high for malaria (64.8%), but low for dengue (26.3%) and Chikungunya (1.7%). Most respondents reported being bothered by mosquitoes mostly at night (53.4%) or in the evening (40.7%). In addition to insecticidal bednets, which are used primarily against malaria, preventive measures for Aedes-borne diseases are limited. Conclusions This study identified significant potential risk of Aedes species, specifically Ae. aegypti sp., and associated diseases, but low perception of risk and inadequate personal protection measures in the study area. This low perception of risk highlights the need to improve public knowledge of the transmission and control of Aedes-borne diseases