Kelvin Mtei - Academia.edu (original) (raw)

Papers by Kelvin Mtei

Plants with pesticidal properties have been investigated for decades as alternatives to syn-theti... more Plants with pesticidal properties have been investigated for decades as alternatives to syn-thetics, but most progress has been shown in the laboratory. Consequently, research on pesticidal plants is failing to address gaps in our knowledge that constrain their uptake. Some of these gaps are their evaluation of their efficacy under field conditions, their eco-nomic viability and impact on beneficial organisms. Extracts made from four abundant weed species found in northern Tanzania, Tithonia diversifolia, Tephrosia vogelii, Vernonia amyg-dalina and Lippia javanica offered effective control of key pest species on common bean plants (Phaseolus vulgaris) that was comparable to the pyrethroid synthetic, Karate. The plant pesticide treatments had significantly lower effects on natural enemies (lady beetles and spiders). Plant pesticide treatments were more cost effective to use than the synthetic pesticide where the marginal rate of return for the synthetic was no different from the untr...

This study assessed the uptake and distribution of fluoride in maize and beans grown in fluoride ... more This study assessed the uptake and distribution of fluoride in maize and beans grown in fluoride contaminated soils, (Ngarenanyuki) around Mount Meru in Northern Tanzania during the rainy season. The study revealed that fluoride uptake increases with increasing fluoride concentration in soils except in a stem and root part of maize and beans respectively. It was observed that fluoride accumulation followed the order of soil >roots > leaves >stem >grain > cob for maize, while the order soil> root> grain> stem was observed for the beans. when the soil contained 116.93ppm of fluoride, the corresponding plants harvested had the mean fluoride accumulation (ppm dry weight) in root, leaves, stem, grain, and cob of maize of 38.560, 24.251, 10.629, 7.7756 and 2.100 respectively, while the soil with 129.2ppm mean fluoride concentration, the accumulation in root, grain, and stem of beans were 16.27, 11.328 and 8.459 respectively. It was reported that beans plant had a h...

n experiment was conducted in Northern Tanzania in two stations: Lyamungu Research Centre, Moshi ... more n experiment was conducted in Northern Tanzania in two stations: Lyamungu Research Centre, Moshi and in a green house at Nelson Mandela African Institution of Science and Technology, Tengeru, Arusha, Tanzania. The experiment was laid down in a factorial arrangement. Factor 1 comprised of three climbing bean varieties: Cheupe, Selian 2005 and Selian 2006. Factor 2 were two inoculation treatments viz [a] inoculation with Rhizobium spp. and [b] without inoculation. Factor 3 included four fertiliser levels [0 kg K/ha, 20 kg K/ha , 30 kg P/ha and 20 kg K/ha + 30 kg P/ha]. The experiment was replicated four times and the growth parameters measured were plant height, number of leaves per plant and plant diameter. Chlorophyll content was extracted using dimethylsulphoxide [DMSO] and the absorbance determined at 645nm and 663nm by using UV/Visible spectrophotometer. The results showed that plant height, number of leaves per plant and plant diameter increased significantly [P < 0.001, P &l...

Research Article published by World Research Journal of Agricultural Sciences Vol. 3(2), December... more Research Article published by World Research Journal of Agricultural Sciences Vol. 3(2), December 2016.

The effectiveness of 1, 5, and 10% w/v of aqueous extracts of Croton dichogamus, Tephrosia vogeli... more The effectiveness of 1, 5, and 10% w/v of aqueous extracts of Croton dichogamus, Tephrosia vogelii, and Syzygium aromaticum and their mixture (2.5 and 5%) was evaluated against Myzus persicae on Brassica oleracea under field conditions. The synthetic chemical insecticide, chlorpyrifos, was used as positive control, and water and water plus soap were used as negative controls. Aqueous extracts significantly ( P ≤ 0.05 ) lowered M. persicae population compared with negative controls. The 5% of the aqueous extract from mixed plants and 10% of each plant used in this study significantly ( P ≤ 0.01 ) reduced aphid, M. persicae population comparable to chlorpyrifos in 2019 and 2020. However, the 1 and 5% concentrations of aqueous extracts of C. dichogamus, T. vogelii, and S. aromaticum and 2.5% of aqueous extracts from the mixed plants significantly lowered the population of M. persicae compared with negative controls in 2019 and 2020 wet seasons. The weekly observations revealed that, at...

Sustainability, 2021

Soil organic carbon (SOC) is widely recognised as pivotal in soil function, exerting important co... more Soil organic carbon (SOC) is widely recognised as pivotal in soil function, exerting important controls on soil structure, moisture retention, nutrient cycling and biodiversity, which in turn underpins a range of provisioning, supporting and regulatory ecosystem services. SOC stocks in sub-Saharan Africa (SSA) are threatened by changes in land practice and climatic factors, which destabilises the soil system and resilience to continued climate change. Here, we provide a review of the role of SOC in overall soil health and the challenges and opportunities associated with maintaining and building SOC stocks in SSA. As an exemplar national case, we focus on Tanzania where we provide context under research for the “Jali Ardhi” (Care for the Land) Project. The review details (i) the role of SOC in soil systems; (ii) sustainable land management (SLM) techniques for maintaining and building SOC; (iii) barriers (environmental, economic and social) to SLM implementation; and (iv) opportuniti...

Earth Surface Processes and Landforms, 2021

Soil resources in parts of Tanzania are rapidly being depleted by increased rates of soil erosion... more Soil resources in parts of Tanzania are rapidly being depleted by increased rates of soil erosion and downstream sediment transport, threatening ecosystem health, water and livelihood security in the region. However, incomplete understanding to what effect the dynamics of soil erosion and sediment transport are responding to land-use changes and climatic variability are hindering the actions needed to futureproof Tanzanian land-use practices. Complementary environmental diagnostic tools were applied to reconstruct the rates and sources of sedimentation over time in three Tanzanian river systems that have experienced changing land use and climatic conditions. Detailed historical analysis of sediment deposits revealed drastic changes in sediment yield and source contributions. Quantitative sedimentation reconstruction using radionuclide dating showed a 20-fold increase in sediment yield over the past 120 years. The observed dramatic increase in sediment yield is most likely driven by increasing land-use pressures. Deforestation, cropland expansion and increasing grazing pressures resulted into accelerating rates of sheet erosion. A regime shift after years of progressive soil degradation and convergence of surface flows resulted into a highly incised landscape, where high amounts of eroded soil from throughout the catchment are rapidly transported downstream by strongly connected ephemeral drainage networks. By integrating complementary spatial and temporal evidence bases, this study demonstrated links between land-use change, increased soil erosion and downstream sedimentation. Such evidence can guide stakeholders and policy makers in the design of targeted management interventions to safeguard future soil health and water quality.

Journal of Environmental Psychology, 2020

Extensive land degradation is a global problem that presents a critical threat to pastoralists' w... more Extensive land degradation is a global problem that presents a critical threat to pastoralists' welfare in East Africa and beyond. Although the reasons for this environmental problem are complex, it is likely to be exacerbated by communal land management practices that have become suboptimal due to changes in land access and population growth. In the present paper we make initial steps towards addressing the problem by exploring socio-psychological predictors of willingness to protect communal land from degradation among Maasai pastoralists in Northern Tanzania. Based on the social identity approach and existing evidence for the role of group processes in proenvironmental action, we have developed and tested a path model predicting willingness to protect communal land. The results demonstrate that community identification is linked to willingness to act via perceived development of action-consistent group and personal norms. In addition, multiple groups analysis demonstrated a number of gender differences within the model. The results are broadly consistent with the existing social identity models of pro-environmental action, extending them into a novel context, and offering practical implications for addressing the issue of pastoralist land degradation.

Land Degradation & Development, 2020

Land, 2020

Achieving change to address soil erosion has been a global yet elusive goal for decades. Efforts ... more Achieving change to address soil erosion has been a global yet elusive goal for decades. Efforts to implement effective solutions have often fallen short due to a lack of sustained, context-appropriate and multi-disciplinary engagement with the problem. Issues include prevalence of short-term funding for ‘quick-fix’ solutions; a lack of nuanced understandings of institutional, socio-economic or cultural drivers of erosion problems; little community engagement in design and testing solutions; and, critically, a lack of traction in integrating locally designed solutions into policy and institutional processes. This paper focusses on the latter issue of local action for policy integration, drawing on experiences from a Tanzanian context to highlight the practical and institutional disjuncts that exist; and the governance challenges that can hamper efforts to address and build resilience to soil erosion. By understanding context-specific governance processes, and joining them with reali...

This is a PDF file of an article that has undergone enhancements after acceptance, such as the ad... more This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.

Agronomy, 2020

Banana is an important crop in high altitude areas of Tanzania, grown widely both as a food stapl... more Banana is an important crop in high altitude areas of Tanzania, grown widely both as a food staple and as the main source of income. However, its production is constrained by low soil fertility, a result of gradual nutrient mining by the crop. Currently, soil fertility management in banana-based farming systems in the country relies mainly on applications of animal manure. However, the amount of manure produced in most farms is not enough to replenish soil fertility due to the small number of animals kept by smallholder resource-poor farmers who are the major producers in the country. Field experiments were conducted at three sites with varying soil types and contrasting weather conditions along the altitudinal gradients on the slopes of the volcanic mountains of Kilimanjaro and Meru, northern Tanzania to (1) investigate the effect of mineral nitrogen (mineral N) fertilizer applications on the growth and yield of Mchare banana (Musa spp., AA, a traditional East African highland cook...

Journal of Environmental Psychology, 2019

Regional Environmental Change, 2019

Increased soil erosion is one of the main drivers of land degradation in East Africa's agricultur... more Increased soil erosion is one of the main drivers of land degradation in East Africa's agricultural and pastoral landscapes. This wicked problem is rooted in historic disruptions to co-adapted agro-pastoral systems. Introduction of agricultural growth policies by centralised governance resulted in temporal and spatial scale mismatches with the complex and dynamic East African environment, which subsequently contributed to soil exhaustion, declining fertility and increased soil erosion. Coercive policies of land use, privatisation, sedentarisation, exclusion and marginalisation led to a gradual erosion of the indigenous social and economic structures. Combined with the inability of the new nation-states to provide many of the services necessary for (re)developing the social and economic domains, many communities are lacking key components enabling sustainable adaptation to changing internal and external shocks and pressures. Exemplary is the absence of growth in agricultural productivity and livelihood options outside of agriculture, which prohibits the absorption of an increasing population and pushes communities towards overexploitation of natural resources. This further increases social and economic pressures on ecosystems, locking agro-pastoral systems in a downward spiral of degradation. For the development and implementation of sustainable land management plans to be sustainable, authorities need to take the complex drivers of increased soil erosion into consideration. Examples from sustainable intensification responses to the demands of population increase, demonstrate that the integrity of locally adapted systems needs to be protected, but not isolated, from external pressures. Communities have to increase productivity and diversify their economy by building upon, not abandoning, existing linkages between the social, economic and natural domains. Locally adapted management practices need to be integrated in regional, national and supra-national institutions. A nested political and economic framework, wherein local communities are able to access agricultural technologies and state services, is a key prerequisite towards regional development of sustainable agro-pastoral systems that safeguard soil health, food and livelihood security.

Environmental Research Letters, 2018

Implementation of socially acceptable and environmentally desirable solutions to soil erosion cha... more Implementation of socially acceptable and environmentally desirable solutions to soil erosion challenges is often limited by (1) fundamental gaps between the evidence bases of different disciplines and (2) an implementation gap between science-based recommendations, policy makers and practitioners. We present an integrated, interdisciplinary approach to support co-design of land management policy tailored to the needs of specific communities and places in degraded pastoral land in the East African Rift System. In a northern Tanzanian case study site, hydrological and sedimentary evidence shows that, over the past two decades, severe drought and increased livestock have reduced grass cover, leading to surface crusting, loss of soil aggregate stability, and lower infiltration capacity. Infiltration excess overland flow has driven (a) sheet wash erosion, (b) incision along convergence pathways and livestock tracks, and (c) gully development, leading to increased hydrological connectivity. Stakeholder interviews in associated sedenterising Maasai communities identified significant barriers to adoption of soil conservation measures, despite local awareness of problems. Barriers were rooted in specific pathways of vulnerability, such as a strong cattle-based cultural identity, weak governance structures, and a lack of resources and motivation for community action to protect shared land. At the same time, opportunities for overcoming such barriers exist, through openness to change and appetite for education and participatory decision-making. Guided by specialist knowledge from natural and social sciences, we used a participatory approach that enabled practitioners to start co-designing potential solutions, increasing their sense of efficacy and willingness to change practice. This approach, tested in East Africa, provides a valuable conceptual model around which other soil erosion challenges in the Global South might be addressed.

International Journal of Current Microbiology and Applied Sciences, 2017

Industrial Crops and Products, 2017

Plants with pesticidal properties have been investigated for decades as alternatives to synthetic... more Plants with pesticidal properties have been investigated for decades as alternatives to synthetics, but only a handful have been commercialised and developed as non-food cash crops. One of the reasons why pesticidal plants are failing to deliver new pesticidal products is that they are often not evaluated under field conditions by farmers. Furthermore, many aspects of pesticide use related to environmental safety, such as their impact on beneficial organisms, remain under-evaluated. With a view to overcoming these bottlenecks, extracts made from six abundant weed species found across sub-Saharan Africa (Bidens pilosa, Lantana camara, Lippia javanica, Tithonia diversifolia, Tephrosia vogelii and Vernonia amygdalina) were evaluated in on-station and on-farm trials over two years (2015 and 2016) in two different countries (Tanzania and Malawi) on common bean plants (Phaseolus vulgaris). All plant species offered effective control of key pest species that was comparable in terms of harvested bean yield to a synthetic pyrethroid. Furthermore, the plant pesticide treatments had significantly lower negative effects on natural enemies (hover flies, lacewings, ladybird beetles and spiders). Thus, pesticidal plants were better able to support ecosystem services whilst effectively managing pests. Small holder farmer rankings on the perceived efficacy of the different plant species indicated that T. vogelii was the most preferred and effective, achieving bean yields as good as the synthetic, if not better. As T. vogelii is fast growing with a well-known and understood phytochemistry, it is an excellent candidate for commercial development to supplement pyrethrum production by African small holder farmers.

Journal of Agricultural Science, 2016

Declining crops yield in the smallholder farmers cropping systems of sub-Saharan African (SSA) pr... more Declining crops yield in the smallholder farmers cropping systems of sub-Saharan African (SSA) present the need to develop more sustainable production systems. Depletion of essential plant nutrients from the soils have been cited as the main contributing factors due to continues cultivation of cereal crops without application of organic/ inorganic fertilizers. Of all the plant nutrients, reports showed that nitrogen is among the most limiting plant nutrient as it plays crucial roles in the plant growth and physiological processes. The most efficient way of adding nitrogen to the soils is through inorganic amendments. However, this is an expensive method and creates bottleneck to smallholder farmers in most countries of sub-Saharan Africa. Legumes are potential sources of plant nutrients that complement/supplement inorganic fertilizers for cereal crops because of their ability to fix biological nitrogen (N) when included to the cropping systems. By fixing atmospheric N2, legumes offe...