Department of Crop Science
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Item Effects of blended fertilizers on soil chemical properties of mature tea fields in Kenya(2018-06) Sitienei, Kibet; Kamiri, Hellen W.; Nduru, Gilbert M.; Kamau, David M.Kenya’s tea industry depends predominantly on imported NPK fertilizers to replenish nutrients removed through plucking. In this respect, two blended fertilizers containing NPKS 25:5:5:4+9Ca+2.6Mg and NPKS 23:5:5:4+10Ca+3Mg with trace elements have been produced in the country. However, contribution of the blended fertilizers to optimal tea yields had not been determined. The study aimed to evaluate the optimal levels of the two blended fertilizers on tea grown in the highlands of Kenya. The blended fertilizers were evaluated in two sites, i.e. Timbilil estate in Kericho and Kagochi farm in Nyeri. The trial was laid out in a randomized complete block design with two blended fertilizers and the standard NPK 26:5:5 as a control. The treatments were applied at four fertilizer rates (0-control, 75, 150 and 225 kg N ha-1 yr-1), with three replications. The results showed that application of 225 kg N ha-1 yr-1 blended fertilizer NPKS 25:5:5:4+9Ca+2.6Mg in Timbilil produced mean yield of 2,995 kg Mt ha-1 compared with 3,099 kg Mt ha-1 from the standard NPK. In Kagochi, the highest yield was 1,975 kg Mt ha-1 obtained from the application of the same blended fertilizer NPKS 25:5:5:4+9Ca+2.6Mg at 75 kg N ha-1 yr-1. The highest yields in both sites were obtained during a warm-dry season except in 2015–2016. This study concluded that based on the annual and seasonal yields, the two blended fertilizers and the standard type had the same effectiveness, irrespective of clones and sites. However, the fertilizer rates affected the tea yield.Item Nutrient Budget and Economic Assessment of Blended Fertilizer Use in Kenya Tea Industry(Hidawi, 2018-11-18) Sitienei, Kibet; Kamiri, Hellen W.; Nduru, Gilbert M.; Kamau, David M.Kenya’s tea industry depends predominantly on imported compound NPK fertilizers to replenish nutrients removed through plucking. These fertilizers cannot be easily manipulated for specific soils and tea clones. They also frequently become hazardous within tea-growing environments. In this respect, two fertilizer blends containing NPKS 25 : 5 : 5 : 4 + 9Ca + 2.62Mg and NPKS 23 : 5 : 5 : 4 + 10Ca + 3Mg with trace elements have been produced commercially in the country. However, the extent to which the blended fertilizers may contribute to optimal economic gains without degrading the environment has not been determined. This was the knowledge gap that this study seeks to address. The goal of this study was to evaluate the economic efficacy of fertilizer blends with the aim of identifying optimal levels of application which would maximize tea productivity with minimal negative impacts on the environment. The study hypothesized that blended fertilizers maximize productivity of tea clones with minimal environmental damage. The fertilizer blends were evaluated in two study sites, i.e., Timbilil Estate in Kericho and Kagochi farm in Nyeri. The sites were selected purposefully, one in the eastern and the other in the western tea-growing areas. The trial was laid out in randomized complete block design with two fertilizer blends and the standard NPK 26 : 5 : 5 as control. The treatments were applied at four fertilizer rates (0 (control), 75, 150, and 225 kg·N·ha−1·yr−1), replicated thrice. Leaf samples were collected and analyzed for nutrient uptake as well as associated yields and economic trends. The economic optimum nitrogen rate (EONR) was achieved at 75 kg·N·ha−1·yr−1 at Kagochi with all fertilizers, while at Timbilil, EONR was variable, between 75 and 225 kg·N·ha−1·yr−1 with fertilizer types. This study has shown that, based on the economic point of view, Blend “A” was the most efficient and consistent fertilizer in production and economic returns across the two sites.Item EFFECTS OF BLENDED FERTILIZERS ON YIELDS OF MATURE TEA CLONES TRFK 6/8 AND BBK 35 GROWN IN KENYAN HIGHLANDS(2018-08) Sitienei, Kibet; Kamiri, Hellen Wangechi Kamiri; Nduru, Gilbert M.; Kamau, DavidKenya’s tea industry depends predominantly on imported NPK fertilizers to replenish nutrients removed through plucking. In this respect, two blended fertilizers containing NPKS 25:5:5:4+9Ca+2.6Mg and NPKS 23:5:5:4+10Ca+3Mg with trace elements have been produced in the country. However, contribution of the blended fertilizers to optimal tea yields had not been determined. The study aimed to evaluate the optimal levels of the two blended fertilizers on tea grown in the highlands of Kenya. The blended fertilizers were evaluated in two sites, i.e. Timbilil estate in Kericho and Kagochi farm in Nyeri. The trial was laid out in a randomized complete block design with two blended fertilizers and the standard NPK 26:5:5 as a control. The treatments were applied at four fertilizer rates (0-control, 75, 150 and 225 kg N ha-1 yr-1), with three replications. The results showed that application of 225 kg N ha-1 yr-1 blended fertilizer NPKS 25:5:5:4+9Ca+2.6Mg in Timbilil produced mean yield of 2,995 kg Mt ha-1 compared with 3,099 kg Mt ha-1 from the standard NPK. In Kagochi, the highest yield was 1,975 kg Mt ha-1 obtained from the application of the same blended fertilizer NPKS 25:5:5:4+9Ca+2.6Mg at 75 kg N ha-1 yr-1. The highest yields in both sites were obtained during a warm-dry season except in 2015-2016. This study concluded that based on the annual and seasonal yields, the two blended fertilizers and the standard type had the same effectiveness, irrespective of clones and sites. However, the fertilizer rates affected the tea yield.Item Community Monitoring of Forest Carbon Stocks and Safeguards Tracking in Kenya: Design and Implementation Considerations(Scientific Research Publishing Inc, 2015-04) Nduru, Gilbert M.; Ucakuwun, Elias K.; Gichu, Alfred N.; Kinyanjui, James M.; Wegulo, Francis N.; McCall, Michael K.; Muchemi, Julius G.This paper investigates modalities required to design and implement community monitoring of forest carbon stock changes and safeguards implementation in Kenya. General principles and elements were drawn from the UNFCCC REDD+ policy frameworks for developing modalities and procedures for designing community forest monitoring system. The paper utilised policy analysis approach used to derive monitoring goals and objectives by assessing the compatibility of Kenya’s policy and legislative framework with monitoring elements provided in the UNFCCC REDD+ policy mechanism. The elements included monitoring goals, objectives, questions, indicators, and meth- ods and tools. Two goals were identified which included, reduction of forest carbon emissions (ER) and monitoring of multiple social and environmental safeguards (SG). Five ER related objectives were identified to include: forest reference emission levels or forest reference levels, drivers of deforestation and forest degradation, Land use activities, eligible ER actions and estimation of forest emissions. Six objectives guiding SG were identified to include: policy, governance, human rights, socio-economic, biodiversity and environmental concerns. Corresponding questions to the goals and objectives were systematically designed. In turns, indicators, depicting quantitative and qualitative measurements, which best provided answers to questions were identified. The various methods and tools used by communities around the world in providing data and information re- quired to satisfy the indictors were identified through literature review. The review identified four methods and tools that included: Remote Sensing and GIS, GPS survey, smartphone survey and Ground trothing. Smartphone and cloud-based server technology were found to be the recent emergent tools in aiding community monitoring of REDD+ projects. The paper argues that local communities and indigenous peoples have the capability and capacity to monitor and undertake forest carbon monitoring and tracking of implementation of safeguards if supported with relevant training; compensated for the time, labour and knowledge they contribute to the process; pro- vided with feedback and involved decision making process.