RP-Department of Agricultural Sciences and Technology
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Item Addressing challenges in communicating adaptation practices to smallholder farmers in Kenya through a radio intervention(Istituto Agronomico per l'Oltremare (IAO), 2017) Mwaniki, Fiona; Gichuki, Charity; Mwangi, Maina; Mburia, Pamela; Wandago, Benson O.Farmers in Africa are particularly vulnerable to the impacts of climate change due to their high dependency on climate-sensitive natural resources. Kenyan farmers are faced with limited public agricultural extension services, narrowing their sources of useful information including adaptive strategies that would help them cope with the impacts of climate change. Radio can be an effective extension tool with the ability to reach many farmers in their local language. This study investigated the potential of radio in influencing the utilization of climate change information by farmers in Kilifi County, located along the Kenyan coast. Education and communication about climate change was undertaken using radio to make available and understandable information to different social and cultural groups. This study revealed that radio can effectively complement other agricultural extension methods and has the potential to engage farmers on climate change issues and motivate them to take action, if appropriate approaches are used. Although very few of the farmers surveyed (33%) reported to have listened to the programs, a high percentage (82%) of those who did implemented the recommended strategies and technologies they heard. The major challenges reported by farmers to accessing the radio programs were lack of a radio and unsuitable program timing. An additional reported challenge was the inability to store or record the programs resulting in farmers relying on their own recollection when implementing strategies. Further research should explore the use of social learning approaches that encourage group rather than individual listenership (such as community listening clubs and community-based radio schools) to overcome these challenges.Item Adoption of Green Building Practices in Langata, Nairobi CityCounty, Kenya(International Journal of Innovative Science and Research Technology, 2024) Chebet, Mercy; Gweyi J.; Kitur E.The increase in greenhouse gas emissions in the atmosphere is a threat to biodiversity. This challenge is being solved by introducing green building practices such as making use of natural lighting, use of solar heating systems, using materials like bamboo which are long-lasting and renewable which aid in reducing energy, water, natural resource consumption and improving waste management in buildings which human beings spend most of their time. Although past research has established a correlation between the level of stakeholder awareness and the rate of uptake of green building technologies, this postulate had not been tested in Nairobi City County. Thus, this study focused on adoption of green building practices in Langata, Nairobi County, Kenya. The study adopted a survey research design; utilizing both quantitative and qualitative methods of data collection including semi-structured questionnaires, inspection checklist and interview schedules.The variables assessed were; the level of green building awareness of construction practitioners, regulatory measures of green building practices and the environmental sustainability indicators ofgreen building technology. The sample size comprised of 100 samples from a total population of 13,126 comprised of construction players including quantity surveyors, construction practitioners and project managers and residential buildings built between 2010 and 2020, two floors and above were the focus of the study. The collected data was analyzed using Microsoft Excel version 13 and SPSS version 25. To test hypotheses, regression analysis was performed. The level of awareness as variables had R-Square of .106, F calculated of 10.357 and p≤.002; The Regulatory measures had R-Square of .172, F- calculated of 15.644 and p≤.003 and environmental sustainability had R Square of .241, F- calculated of 13.742 and p≤.002 on adoption of green building technology in Langata Nairobi County, Kenya. The findings indicated that data was significant and alternative hypotheses were acceptable to be statistically significant. The findings depicted that majority of construction workers were not aware of green building, Kenya Green Building Society and neither were they trained on green building. Regulatory measures were implemented at a moderate extent but green building policies had not been incorporated in the current construction guidelines. The study also showed that green building practices such as waste management, energyand water efficiency are being observed well. The conclusion is that most respondents do not clearly understand green building technology, implementation of the already set green building policies is still a challenge and there is a great change in people’s attitude towards building sustainably. It is recommended that more awareness and training should be done, regulations established and enforced and government should provide incentives to encourage green building technologies. The findings of the study provide additional literature on the subject matter for further research. It also helps policy makers in formulating policies which may enhance the uptakeof green building technology in the study area.Item Advantages of Cotton Based Intercropping System: A Review(Association for Agriculture, Environment and Biotechnology, 2020) Panda, Shravan Kumar; Panda, Pritam; Pramanick, Biswajit; Shankar, Tanmoy; Praharaj, Subhashisa; Saren, Binoy Kumar; Gitari, Harun I.; Brahmachari, Koushik; Hossain, Akbar; Maitra, SagarIntercropping provides ample scope to incorporate at least two or more crops at a time in same piece of land aiming at higher productivity from unit land area through optimized utilization of available resources. Selection of crops, planting geometry and optimum stand and crop maturity are important factors influencing success of intercropping system. Upland cotton, being a moderately long duration and widely spaced crop and having moderate growth rate during early stage, offers suitability for adoption of intercropping. Previous research indicates that under cotton-based intercropping system there is efficient use of resources resulting in not only high productivity from unit area but also in high profitability. The current review article highlights the advantages of cotton-based intercropping system based on previous research findings.Item Aggrandizing soybean yield, phosphorus use efficiency and economic returns under phosphatic fertilizer application and inoculation with Bradyrhizobium(Springer, 2022-08) Akello , Mirriam; Mugwe, Jayne ; Raza, Muhammad Ali ; Seleiman, Mahmoud F. ; Maitra, Sagar; Gitari, Harun H.Item Agricultural Extension Approaches Influencing Uptake of Improved Sorghum Technologies in Embu County, Kenya(Horizon Research Publishing, 2016) Chimoita, E. L.; Onyango, Cecillia M.; Kimenju, John W.; Gweyi-Onyango, Joseph P.Agricultural extension and technology transfer services play a vital role in disseminating research knowledge, skills and income generating strategies among the farming communities in Kenya. However, there exists a kind of disconnect between the amount of information and technologies developed in research centres and what is implemented by the farmers. The study evaluated the access and use of extension approaches in promoting uptake of improved sorghum technologies. The study systematically selected 129 farmers from four villages. Data on farmers’ gender, age, household leadership, occupation and agricultural extension approaches were collected. The study revealed that 83% of the respondents were female out of which, 67% were engaged in improved sorghum production technologies. Besides, 56% young women (20 to 49 years) had embraced the growing of improved sorghum varieties Gadam and Sila 1. Further, mobile phones and radio services were the main means of access to the improved sorghum technologies. In addition, there was a strong positive correlation (r=0.122, P=0.01) between extension approaches and uptake of the sorghum technologies. Besides government agricultural extension agents, visits to progressive farmers and/or research sites and use of demonstration plots contributed to 68% and influenced uptake of improved sorghum technologies. It was concluded that gender, family position and age of the farmer contribute to the uptake of improved sorghum technologies. Moreover, mobile phones and radio technologies play an important role in access of sorghum technologies.Item Agricultural nematology in East and Southern Africa: problems, management strategies and stakeholder linkages(Society of Chemical Industry, 2015) Talwana, H.; Sibanda, Z.; Wanjohi, Waceke J.; Kimenju, W.; Luambano-Nyoni, N.; Massawe, C.; Manzanilla-López, R.H.; Davies, K.G.; Hunt, D.J.; Sikora, R.A.; Coyne, D.; Gowen, S.R.; Kerry, B.R.By 2050, Africa’s population is projected to exceed 2 billion. Africa will have to increase food production more than 50% in the coming 50 years to meet the nutritional requirements of its growing population. Nowhere is the need to increase agricultural productivity more pertinent than in much of Sub-Saharan Africa, where it is currently static or declining. Optimal pest management will be essential, because intensification of any system creates heightened selection pressures for pests. Plant-parasitic nematodes and their damage potential are intertwined with intensified systems and can be an indicator of unsustainable practices. As soil pests, nematodes are commonly overlooked or misdiagnosed, particularly where appropriate expertise and knowledge transfer systems are meager or inadequately funded. Nematode damage to roots results in less efficient root systems that are less able to access nutrients and water, which can produce symptoms typical of water or nutrient deficiency, leading tomisdiagnosis of the underlying cause. Damage in subsistence agriculture is exacerbated by growing crops on degraded soils and in areas of low water retention where strong root growth is vital. This review focuses on the current knowledge of economically important nematode pests affecting key crops, nematode control methods and the research and development needs for sustainable management, stakeholder involvement and capacity building in the context of crop security in East and Southern Africa, especially Kenya, Tanzania, Uganda and Zimbabwe.Item Agro-Ecological Lower Midland Zones IV and V in Kenya Using GIS and Remote Sensing for Climate-Smart Crop Management 49(Springer, 2021) Manzi, Hilda; Gweyi-Onyango, Joseph PFood production in Kenya and Africa in recent past has experienced vagaries of weather fluctuations which ultimately have affected crop yield. Farming in Kenya is localized in specific Agro-ecological zones, hence understanding crop growth responses in particular regions is crucial in planning and management for purposes of accelerating adoption. A number of strategies for adoption and adaptation to changing weather patterns have been deployed yet only limited challenges have been partially addressed or managed. This chapter examines previous methods used in classifying agro-ecological zones and further provides additional insightful parameters that can be adopted to enable farmers understand and adapt better to the current variable and unpredictable cropping seasons. The chapter scrutinizes past and current documented information on agro-ecological zonal valuations coupled with the use of earth observation components such as air temperature at surface, land surface temperature, evapotranspiration, soil, temperature, and soil and moisture content in order to better understand and effectively respond to new phenomena occurring as a result of climate change in the marginal agricultural areas. Significant variations in precipitation, ambient temperature, soil moisture content, and soil temperature become evident when earth observation data are used in evaluation of agroecological lower midland zones IV and V. The said variations cut across areas within the agro-ecological zones that have been allocated similar characteristics when assigning cropping seasons. The chapter summarizes the outcomes of various streams of contributions that have reported significant shifts or changes in rainfall and temperature patterns across Kenya and wider Eastern Africa region. The chapter highlights the need for re-evaluation of the agro-ecological zones based on the recent earth observation datasets in their diversity. The research emphasizes the use of multiple climate and soil-related parameters in understanding climate change in the other marginal areas of Kenya.Item Agromorphological Performance and Character Association of Finger Millet under Varying Phosphorus Regimes(Macrothink Institute, 2017) Wekha, Wafula Nelson; Korir, Nicholas K.; Siambi, Moses; Ojulong, Henry F.; Gweyi-Onyango, Joseph P.Item Agronomic assessment of phosphorus efficacy for potato (Solanum tuberosum L) under legume intercrops(Taylor & Francis, 2019) Gitari, Harun I.; Shadrack, Nyawade; Kamau, Solomon; Karanja, Nancy N.; Gachene, Charles K. K.; Schulte-Geldermann, ElmarPhosphorus (P) is an essential element and its efficient use is of global importance. This study evaluated the effect of growing potato under legume intercrops on P uptake and use efficiency indices: P harvest index (PHI), P uptake efficiency (PuPE), P partial factor productivity (PPFP) and P partial balance (PPB). The experiment was carried out for four consecutive seasons with treatments comprising potato cultivated under legume intercrops: none (T1), dolichos (Lablab purpureus L) (T2), peas (Pisum sativum L) (T3) and beans (Phaseolus vulgaris L) (T4). Across the seasons, the mean haulm P uptake for T2 (6.7 kg P ha 1 ), T4 (5.5) and T3 (4.5) were 6%, 23% and 36% lower than that observed in T1 (7.1 kg P ha 1 ), respectively. On the other hand, tuber P uptake was highest in T1 (21.8 kg P ha 1 ) and T2 (21.3 kg P ha 1 ) and were significantly higher than 13.2 kg P ha 1 in T3 and 15.1 kg P ha 1 in T4. This had a profound effect on PuPE, which was equally highest in T1 (0.26 kg total P uptake kg 1 P supply) and T2 (0.25) and lowest in T3 (0.16) and T4 (0.18). Similarly, PPFP, PHI and PPB followed a similar trend, with highest values in T1 (57 kg tuber dry matter yield kg 1 P supply, 76.4 kg tuber P uptake kg 1 total plant’s P uptake and 0.20 kg tuber P uptake kg 1 P supply, respectively). Among the tested legume intercrops, dolichos competed least for P with the main crop (potato) hence it can be integrated into potato-based cropping systems without compromising potato tuber yield.Item Agronomic management of yellow passion fruit among farmers in Mbeere Sub-County, Kenya(Horticultural association of Kenya, 2016-09) Mwirigi, P.; Mwangi, M.; Gweyi-Onyango1, J.Yellow passion fruit (Passiflora edulis var. flavicarpa) is emerging as an important high value horticultural crop in Kenya since its introduction five years ago. The fruit is gaining wide adoption in Mbeere Sub County due to its apparent adaptation to the hot arid conditions and tolerance to Fusarium wilt disease. However, the current production levels of the fruit are low due to poor water and nutrient management, erratic rainfall and poor agronomic practices. A study was conducted to assess the agronomic practices and main constraints among the farmers in Mbeere Sub County. A stratified random sampling procedure was used to collect data from 63 households from a total population of 170,950. Data was collected on household demographics, farm size, farming systems, planting materials, fertilizer use and irrigation types. This was carried out through personal interviews with members in each household responsible for management of passion fruit orchards using structured and semistructured questionnaires. The results indicate that the majority of the farmers (65%) grow yellow passion as an intercrop with other food crops. Nevertheless, passion contributes to <10% of the proportion of the farm, though this proportion is expected to increase with expansion in production. Major findings indicate that the main source of planting materials were seedlings from KARLO (44%), use of Yaramillar (44%) as the preferred planting fertilizers and irrigation of crops three times per week (49%). In conclusion, yellow passion is a fruit with potential for increased adoption but more detailed studies are needed to clearly identify and understand water and nutrient management.Item Application of Bio and Chemical Fertilizers Improves Yield, and Essential Oil Quantity and Quality of Moldavian Balm (Dracocephalum moldavica L.) Intercropped with Mung Bean (Vigna radiata L.)(Wiley Online Library, 2021) Faridvand, Shahin; Rezaei-Chiyaneh, Esmaeil; Battaglia, Martin Leonardo; Gitari, Harun I.; Raza, Muhammad AliIntercropping Moldavian balm with mung bean is an ecological approach for improving resource productivity. A field experiment was conducted over two growing seasons (2018 and 2019) to determine the effect of fertilizer application on yield and essential oil (EO) productivity of Moldavian balm intercropped with mung bean. The experiment had a two-factor randomized complete block design (RCBD) with three replicates. The first factor comprised of five cropping patterns: Moldavian balm sole crop (MBs), mung bean sole crop (MGs), one row each of Moldavian balm +mung bean (1MB:1MG), two rows each of Moldavian balm +mung bean (2MB:2MG), and three rows of Moldavian balm +two rows of mung bean (3MB:2MG). The second factor comprised four fertilizer sources: no fertilizer application (C, control), 100% chemical fertilizer (NPK), 50% chemical fertilizer +100% bacterial fertilizer (NPK+BF), and 100% bacterial fertilizer +100% mycorrhizal fungi (BF+MF). The sole crop fertilized with NPK+BF produced the highest seed yields for MG (1189 kg/ha) and MB (7027 kg/ha), while 3MB:2MG fertilized with NPK+BF had the highest nutrient contents. Moldavian balm produced the highest EO content and yield in 2MB:2MG fertilized with NPK+BF. The EO of MB mainly comprised geranyl acetate (30–39%), geranial (20–31%), neral (18–24%), and geraniol (3–8%). In addition, the 3MB:2MG intercropping treatment fertilized with NPK+BF had the highest land equivalent ratio (LER = 1.35). We recommend an intercropping ratio of 2MB:2MG fertilized with NPK+BF is recommended as an alternative and eco-friendly strategy for farmers to improve EO quantity and quality.Item Appropriate plant growth regulators and genotypes for propagation of jojoba (simmondsia chinensis L.) cuttings in semi-arid areas of Voi, Kenya(2016) Inoti, Shadrack; Chamshama, Shabani; Lulandala, Lulther; Thagana, Wilson; Dodson, RobItem Artificial Intelligence for Maximizing Agricultural Input Use Efficiency: Exploring Nutrient, Water and Weed Management Strategies(Tech Science Press, 2024-05-30) Sow, Sumit; Ranjan, Shivani; Seleiman, Mahmoud F.; Alkharabsheh, Hiba M.; Kumar, Mukesh; Kumar, Navnit; Padhan, Smruti Ranjan; Roy, Dhirendra Kumar; Nath, Dibyajyoti; Gitari, Harun; Wasonga, Daniel O.Agriculture plays a crucial role in the economy, and there is an increasing global emphasis on automating agricultural processes. With the tremendous increase in population, the demand for food and employment has also increased significantly. Agricultural methods traditionally used to meet these requirements are no longer adequate, requiring solutions to issues such as excessive herbicide use and the use of chemical fertilizers. Integration of technologies such as the Internet of Things, wireless communication, machine learning, artificial intelligence (AI), and deep learning shows promise in addressing these challenges. However, there is a lack of comprehensive documentation on the application and potential of AI in improving agricultural input efficiency. To address this gap, a desk research approach was used by utilizing peer-reviewed electronic databases like PubMed, Scopus, Google Scholar, Web of Science, and Science Direct for relevant articles. Out of 327 initially identified articles, 180 were deemed pertinent, focusing primarily on AI’s potential in enhancing yield through better management of nutrients, water, and weeds. Taking into account research findings worldwide, we found that AI technologies could assist farmers by providing recommendations on the optimal nutrients to enhance soil quality and determine the best time for irrigation or herbicide application. The present status of AI-driven automation in agriculture holds significant promise for optimizing agricultural input utilization and reducing resource waste, particularly in the context of three pillars of crop management, i.e., nutrient, irrigation, and weed management.Item Assessing and Enhancing the Impact of Cotesia plutellae in Management of Diamondback Moth Plutella xylostella on Kale Brassica Oleracea var. acephala in Semi-Arid Areas of Kenya(American Research Institute for Policy Development, 2017) Kahuthia-Gathu, R.; Mwangi, M.Diamondback moth (DBM, Plutella xylostella L.) is a major pest of crucifers which can cause yield losses of up to 100% if left unmanaged. Classical biological control of DBM was adopted in Machakos and Kitui County through Cotesia plutellae imported from South Africa in 2002 and released in March 2004 in farmers’ fields where kale Brassica Oleracea var. acephala is one of the major leafy vegetables. Preliminary studies in 2004- 2006 showed that the parasitoid had not established in the release sites and augmentation releases were done in 2006. Monthly surveys were conducted (May 2012 to April 2013) to assess the spread and contribution of C. plutellae in the management of the DBM. Brassica oleracea var. acephala fields in twenty five randomly selected farms were sampled for number of DBM larvae and pupae, damage, parasitism and parasitoid guild. The data was recorded from 20 plants in each selected farm. The DBM larvae and pupae were placed in plastic containers and taken to the laboratory for DBM or parasitoid emergence. Results revealed that the mean number of DBM/plant in Kitui and Matuu ranged from 0.4 to 2.5 and 0.3 to 3.5, respectively. Mean damage score ranged from 1.2 to 1.6 in both regions, which was positively correlated to the number of DBM on B. oleracea var. acephala. Hymenopteran parasitoids recovered from DBM included Cotesia plutellae, Diadegma semiclausum, D. mollipla, Apanteles sp., Chelonus sp., Oomyzus sokolowskii and Itoplectis sp., while the hyper parasitoids included Mesochorus sp., Pteromalus sp., Notanisomorphella sp., Eurytoma rosae and Eurytoma sp., Brachymeria sp. and Pediobius sp. Cotesia plutellae was the most abundant parasitoid followed by D. semiclausum. Diversity of parasitoids varied between months and study sites. Cotesia plutellae had established and spread beyond the release sites contributing between 40 and 90% parasitism while the indigenous parasitoids Itoplectis sp., Apanteles sp., and D. mollipla contributed less than 5% parasitism. The results show the spread and establishment of C. plutellae in the study sites. In conclusion, there is need for continuous training and educating the farmers to conserve the parasitoids that have contributed in the reduction of the DBM and damage on the crop. This has contributed in the reduction on pesticides use, spraying regime and eventual reduction of cost of production and residues on the produce.Item Assessing the Potential of Biochar for Improving Soil Physical Properties and Tree Growth(hindawi, 2021) Mwadalu, Riziki; Mochoge, Benson; Danga, Benjamin)e effect of biochar on tree growth and soil physical properties as indicated in literature is still outstanding. Information on the effect of biochar on tree growth is limited, and the available literature has recorded conflicting results. )erefore, a field experiment using Casuarina equisetifolia (Casuarina) as the test crop under different biochar rates was conducted. Four biochar rates (0, 2.5, 5.0, and 7.5 t ha−1) were used as treatments, each replicated three times. Generally, biochar-amended plots recorded higher Casuarina height, collar diameter, and diameter at breast height (DBH). )e application of biochar at 7.5 t ha−1 resulted in higher Casuarina height of up to 20.2% compared to the control. On the contrary, application of biochar at 2.5 t ha−1 recorded higher collar diameter of up to 30.2% compared to the control. Generally, there was a decrease in soil bulk density with biochar application. Bulk density decreased linearly with increasing biochar application rates with biochar application rate of 7.5 t ha−1 recording the lowest bulk density (0.99 g cm−3). )ere was a decrease in bulk density of up to 25% compared to the control with the biochar application rate of 7.5 t ha−1. Biochar application rate of 7.5 t ha−1 also recorded the highest soil moisture content across the assessment periods. Biochar-amended plots recorded higher soil moisture content than the untreated control. )ere was increase in soil moisture content following biochar application of up to 108% with the application of biochar at 7.5 t ha−1 compared to the untreated control. )e increase in soil moisture content with biochar application can be attributed to biochar’s porous nature and large surface area. )ese results suggest that the use of biochar has the potential of enhancing Casuarina growth while enhancing soil physical properties by decreasing bulk density and enhancing soil moisture storage.Item Assessment of genetic variation of selected spiderplant (Cleome gynandra L.) morphotypes from Western Kenya(Academic Journals, 2009-06) Muasya, R. M.; K'Opondo, F. B. O; Rheenen, H. A.Item Assessment of Input-Output Transformation in Purple Passion Fruit Production in Central-Eastern and North-Rift, Kenya(Maxwell Scientific Organization, 2013-06-20) Gichim, C. Karani; Macharia, I.; Mwangi, M.Over the last decade, there has been increasing economic importance of purple passion fruit in Kenya. The primary objective of this study was to assess the input-output transformation process in purple passion fruit production in Central-Eastern and North-Rift Kenya in order to identify avenues for improving and sustaining productivity. Cross-sectional data from 123 multistage sampled farmers was collected using a structured questionnaire, which was subjected to stochastic frontier in STATA 11 for analysis. The results showed that the purple passion fruit production input elasticity was 0.95 which represented Decreasing Returns to Scale (DRS). The results also indicated that passion fruit farm size and manure had a negative and positive significant effect on purple passion fruit yields at 1% significance level, respectively. On the other hand, number of seedlings and hired labor variables had positive and significant effect on the fruit yields at 5% level. The results implied that passion farm size was overused while manure, number of seedlings and hired labor were underused. The gamma parameter (γ) was 0.86 which indicates that 86% of the total variation in purple passion fruit output was due to technical inefficiencies. The overall mean Technical Efficiency (TE) was 59% which indicated a cost saving estimate of 32% for the average farmer in attaining the TE of the most technically efficient farmer (86%). The study recommends up-scaling of passion fruit farming information systems so as to provide a basis for optimal use of production resources.Item Assessment of performance of smallholder dairy farms in Kenya: an econometric approach(F.a.C.T Ltd -, 2014) Mugambi, David Kimenchu; Mwangi, Maina; Wambugu, Stephen Kairu.; Gitunu Antony M.MObjective: The aim of the study was to estimate the technical and cost efficiencies of smallholder dairy farms in Kenya (Embu and Meru counties). Methodology and results: Data were collected through a cross-sectional survey from 135 (96 in Embu and 39 Meru) randomly sampled farms using semi-structured questionnaires. Stochastic frontier production and cost functions were estimated using the maximum likelihood estimation (MLE) technique. It revealed zero-grazed herds of four animals (mainly Friesians and Ayrshires) on two-acre sized farms that practice mixed crop-livestock farming system. The animals were underfed daily with roughages (52.2 Kg), concentrates (2.2 Kg) and mineral supplements (37 g); producing 15 Kg of milk on average. The major factors influencing milk output were the number of lactating cows and the amounts of roughages, concentrates and mineral supplements, while the prices of roughages and labour caused most variation in its production cost. The mean farmers’ technical and cost efficiencies were 83.7 and 95.6%, respectively. The production model coefficient was 2.11. These results implied that milk production could be increased by 16.3% through better use of available resources given the current state of technology without extra cost, while the cost of milk production could be decreased by about 4.4% without decreasing output. Conclusion and application of results: The results indicate that optimization of farm efficiencies could increase milk yields while concurrently lowering its production cost. The study further provides evidence that any efforts towards reducing land sub-division and promotion of enterprise specialization could increase milk affordability.Item Assessment of Sweet Potato Propagules for Re- Infection by Various Viruses in East Kamagak Location – Homa Bay County-Kenya(SCIENCEDOMAIN International, 2016) Onyango, Rosally A.; Thagana, Wilson M.; Karanja, Laura; Onyango-Gweyi, JosephItem Assessment of the 2006 Abuja Fertilizer Declaration with Emphasis on Nitrogen Use Efficiency to Reduce Yield Gaps In Maize Production(Frontiers, 2022) Winnie, Ntinyari; Giweta, Mekonnen; Gweyi-Onyango, Joseph; Mochoge, Benson; Mutegi, James; Nziguheba, Generose; Masso, CarelessThe Abuja Fertilizer Declaration in 2006 recommended the increase of fertilizer use from the current practice for Sub-Saharan Africa (SSA) to achieve food sufficiency and improve soil fertility status. However, the current recommended rates of fertilizer have not been evaluated for specific crops on their potential to reduce the yield gap and optimize nitrogen use efficiency (NUE). In this study, with nitrogen (N) being a significant yield-determinant nutrient, four N use scenarios were drawn from existing recommendations and were evaluated under field conditions for maize crops in two catchments of the Lake Victoria basin. The scenarios included Business as Usual (BAU, 0 kg N ha−1 ), 25% of the Abuja declaration (ADS 12.5 kg N ha−1 ), 50% of the Abuja declaration (ADS 25 kg N ha−1 ), and Abuja declaration–Abuja scenario (ADS, 50 kg N ha−1 ). The results revealed that increasing N input levels significantly influenced the growth and yield of maize crops. The ADS scenario recorded the highest grain yield increase (167.39%) in Nyando and 103.25% in Rangwe catchments compared to the BAU scenario. N deficits were observed in all the N use scenarios with a range of −66.6 to −125.7 kg N ha−1 in Nyando and −62.5 to −105.4 kg N ha−1 in Rangwe catchments with the 50% ADS scenario having the highest deficits. The deficits imply that the added N input is insufficient to create an N balance for optimal NUE with consequent high risks of soil N mining. In both catchments, all N use scenarios were within the recommended agro-physiological N efficiency (APEN) level of between 40 and 60 kg kg−1 N. The partial N balance obtained at Nyando (1.56–3.11) and Rangwe (1.10–4.64) was higher than the optimal values, a sign of insufficiency of N inputs and possible risk of soil N depletion in all the scenarios. Our findings conclude that the proposed N rates in the region are still very low for food sufficiency and optimized NUE. Therefore, there is a need to explore other sources of N such as biological N fixation and organic manure and inform policy- and decision-makers to recommend higher rates beyond the “Abuja declaration” with the prospect of reaching target yield and optimizing NUE values based on specific crop recommendations.