CoANRE Students Publications

Heavy Metal Occurrence within Urban Agriculture Practices in Eastern zones of Nairobi City

2026-05-04T07:10:18Z

Heavy Metal Occurrence within Urban Agriculture Practices in Eastern zones of Nairobi City Njenga, John Ng’ang’a Urban agriculture,although growing in importance,farmer practices have to continually adapt to the dynamics of urbanization having implication on quality of produce and public perception. The objective of this research was to assess heavy metal incidence in inputs and food crops for urban farms in eastern zone of Nairobi, determine differences in element uptake by crops and to examine influence of environmental quality of the surrounding spaces. A quasi research design approach was used to identify farm plots for field survey in three locations. Samples of tomatoes (Lycopersicon esculentum), arrowroots (Colocasia esculenta), and kales (Brassica oleraceae var. Acephala), water and soil samples were obtained according to standard procedures. Contents of cadmium, manganese, zinc and lead were analysed using Atomic Absorption/Flame Emission Spectrophotometer. One way ANOVA was applied to examine differences in means of heavy metals between locations and to compare transfer factor (TF) index of the crops. Elements that were above allowable limits in the crops were Cd, Mn, Pb and Zn in arrowroots; Cd and Mn in kales and Cd, Mn and Pb in tomatoes. Cadmium content was highest in farm plots within Kasarani (2.44±0.86 mg/kg) and was significantly different from other two locations (p<0.05, Tukey HSD test). Between the neighbourhood qualities, heavy metal contents were different but not significant (p>0.05) between classes. The mean TF index for the heavy metals decreased in the order Cd>Pb>Zn>Mn. Transfer factor index of> 1 for cadmium was recorded in arrowroots, kales and tomatoes. Based on FAO/WHO standards, the measured heavy metal contents were high for health concern. Produce from areas designated as of low environmental quality, were not necessarily contaminated as perceived. Urban agriculture producers in Nairobi need technical risk reduction measures and legislative support to guarantee quality produce and valuable participation in the urban food system framework. Key words: urban farming, environmental quality, cadmium, lead, transfer factor, edible produce, health risk MSc Research Publication

Survey of the incidence and distribution of groundnut rosette disease in major groundnut-producing regions of Western Kenya

2026-03-26T11:46:51Z

Survey of the incidence and distribution of groundnut rosette disease in major groundnut-producing regions of Western Kenya Were, Eric Osewo Groundnut rosette disease (GRD) is the most important viral disease of groundnuts in sub-Saharan Africa. In Kenya, GRD infection especially before flowering results in 100% loss in pod yield. Surveys were conducted in 2016 and 2017 to determine the incidence and distribution of GRD in five major groundnut growing Counties of western Kenya. A structured questionnaire was used to assess GRD incidence and severity and farmers’ awareness about management of GRD. Reverse transcription (RT) polymerase chain reaction (PCR) was used for the detection of GRD agents in collected symptomatic samples. Results revealed that GRD was prevalent in all the fields of the five counties. The highest mean disease incidence was in Busia County (35.7%) while the lowest incidence was in Siaya (23.1%). The most conspicuous symptoms observed in all the fields inspected were yellow/chlorotic rosette and green rosette. The highest mean disease severity was observed in farmers’ fields in Busia (3.1) and Bungoma (3.0) Counties, while the lowest was observed in Siaya (2.8). RT-PCR detected GRD agents in all the symptomatic samples. This study demonstrated the widespread occurrence of GRD in major growing regions of western Kenya and warrants the implementation of effective virus disease control strategies. Key words: Arachis hypogaea L., field survey, groundnut rosette disease, occurrence, severity. MSc Research Publication

EFFICACY OF TAGETES MINUTA AND TITHONIA DIVERSIFOLIA FORMULATIONS AGAINST MELOIDOGYNE INCOGNITA USING A NOVEL RELEASE APPLICATION TECHNIQUE IN TOMATO

2026-02-24T09:40:34Z

EFFICACY OF TAGETES MINUTA AND TITHONIA DIVERSIFOLIA FORMULATIONS AGAINST MELOIDOGYNE INCOGNITA USING A NOVEL RELEASE APPLICATION TECHNIQUE IN TOMATO Macharia, Rachael Muthoni Tomato (Solanum lycopersicum) is an economically important crop in East Africa and is produced largely by small-scale farmers. The root-knot nematode, Meloidogyne incognita (Kofoid and White) Chitwood, causes serious constraints in tomato production in the African continent. Organic additives of plant origin have been known to control nematodes. The efficacy of different formulations of these additives dispensed as a slow-release in filter bags against M. incognita remains unknown. This study investigated the efficacy of two formulations; powder, and pellet from leaves and stems (above parts) and roots (below parts) of Tithonia diversifolia and Tagetes minuta on M. incognita in tomato. The filter bags were made of non-woven interfacing fusible fabric, and they contained the extracts used in the experiments. The experiment was laid out in a completely randomized design with 18 treatments and replicated four times. Tomato seedlings were inoculated with about 1500 freshly hatched second stage juveniles of M. incognita five days after seedling transplant. Data was collected on root galling, number of egg masses per root, root-knot nematode second-stage juveniles in the soil, and tomato yield and subjected to analysis of variance (ANOVA). Treatment means were compared using the Tukey Studentized Range Test at a 5% probability level (P = 0.05). Results showed that all formulations significantly (P= ˂0.001) reduced nematode populations relative to the untreated control. However, untagged (without filter bag) formulations were about five times better than the tagged (with filter bag) in both the preventive and curative trials at 42- and 84-days post-inoculation (DPI). No significant differences were observed at 126 DPI. Powder formulations of T. minuta roots (79%) and T. diversifolia leaves (78%) significantly (P = ˂0.001) reduced M. incognita juvenile populations followed by pellet formulations of T. minuta leaves (74%) and T. diversifolia roots (72%) relative to the positive control (70%) Bionematon® Powder formulations (79%) reduced RKN populations better than the pellet formulations (73%) but the yield was higher (70.7 t/ha) in the latter. Tagged powder formulations of T. diversifolia roots recorded a 7% decrease in yield in the preventive trial compared to the curative trial. However, within the same trial, tagged pellets of T. minuta roots and the positive control recorded more than 10% increase in yield relative to the curative trial. These findings indicate that formulations of T. minuta and T. diversifolia incorporated in filter bags can be used for management of RKNs in tomato and other vegetable crops. MSc Research Publication

Determinants of finger millet adoption, non-adoption and dis-adoption among smallholder farmers in Nakuru, Kenya

2025-11-13T10:01:18Z

Determinants of finger millet adoption, non-adoption and dis-adoption among smallholder farmers in Nakuru, Kenya Mireri, Richard Nyandigisi Previous studies on technology adoption have treated smallholder farmers’ decisions as being binary. In this article, we assess the adoption, non-adoption and dis-adoptions decisions among smallholder finger millet producers in Nakuru, Kenya. The crop has potential to enhance food security and nutrition in the context of climate change. Data for the study were collected from a household survey of 326 households selected through a multi-stage sampling process. Descriptive and logistic regression analysis was used to analyze the data. The study findings reveal that knowledge levels were higher among the adopters (81.4%), compared to the dis-adopters (45.6%) and non-adopters (58.2%). While attitudes towards finger millet production were generally negative, a large proportion of adopters had positive attitudes towards the economic value of the crop and its contribution to human health. Regression results show that higher levels of knowledge were positively associated with finger millet adoption. As expected, positive attitudes had a positive influence on adoption while concurrently negatively influencing dis-adoption. Further the results suggest that changing attitudes on economic value and the role finger millet plays on human health could improve adoption decisions. The other factors that had a positive influence on adoption were education, income, farming experience, while gender (being female), education (higher), and income had negative influence on dis-adoption. Overall, our results suggest the importance of psychosocial factors (knowledge and attitude), the importance of finger millet to female household heads and resource endowment factors (such as education and income) in sustaining adoption decisions while concurrently dissuading dis-adoption. Keywords: adoption, dis-adoption, non-adoption, attitude, knowledge MSc Research Publication