Theses and Dissertations Collection

Permanent URI for this collectionhttp://10.10.97.169:4000/handle/123456789/39

Browse

Browsing Theses and Dissertations Collection by Subject "Adapting Coffee"

Now showing 1 - 1 of 1
  • Thumbnail Image
    Item
    Adapting coffee (Coffea Arabica, L.) production to climate change through types of seedlings and soil fertility management practices in Tanzania
    (Sokoine University of Agriculture, 2024-05) Mbwambo, Suzana Gasper
    In Tanzania, coffee is the second largest traditional export commodity after tobacco, accounting for 24 % of the country‘s total foreign exchange earnings. Average annual production has stagnated at about 50,000 metric tons over the past 35 years. One of the widely held reasons is climate change, manifested by high rainfall variability and decline as well as increase in temperature. Elsewhere different adaptation strategies like use of shade trees, drought tolerant coffee varieties and organic fertilizer have been proposed to deal with the effect of climate change on coffee production. However, climate change adaptation studies for coffee production in Tanzania are largely missing. An overall objective of this work was to develop agronomic techniques for adapting Coffea arabica, L. production to climate change. Specifically, the study aimed to: 1) asses coffee growers‘ perceptions on climate change; 2) asses the relationship between scientific climate change record and production records; 3) evaluate field performance of compact coffee variety under selected propagation methods and soil fertility amendment practices and 4) determine the role of type of seedling and fertilizer management practices in increasing resilient of coffee species to the changing climate. The study was undertaken in the Northern Highland zone (Kilimanjaro and Arusha regions) and Southern Highland zone (Songwe, Mbeya and Ruvuma regions), purposively selected based on the level of Arabica coffee production. First a survey was conducted to examine smallholder farmers‘ perceptions of climate change. The findings indicate that, 163 (67 %) farmers perceived climate change has been taking place in their areas (increase in temperature and decrease in rainfall); the most influential factors in their perception being level of education, farming experience and access to climatic information. Farmers‘ perceptions were also consistent with meteorological data both pointing to significant decline in rainfall and increase in temperature. Smallholder farmers have been responding to climate change through planting shade trees, use of disease-tolerant varieties, soil fertility management, and irrigation practices. A follow- up study was conducted to assess the impact of current climate change on Tanzania‘s Arabica coffee production. The findings reveal minimum temperature has been increasing at a higher rate than the maximum temperature in both zones. Increase in minimum temperature by 1°C during short rains and annual mean temperature resulted in a significant coffee production decrease in Kilimanjaro and Arusha regions by -6,041 and -4,450 tons respectively. Field experiments were also established to evaluate performance of cutting, grafting and seed propagules when combined with 75 g N. P. K tree-1, 37.5 g N. P. K +10 Kg Farmyard manure (FYM) tree-1 and 37.5 g N. P. K +20 Kg FYM tree-1. Two split plot experiments laid out in a Randomized Complete Block Design with three replications were established at the two locations (Lyamungu-Hai district and Burka - Arusha district) based on the existing climatic gradient; cutting- propagated plants resulted into highest yield ranging between 1800- 3600 Kg green coffee ha-1 while grafted-propagated plants had the lowest green coffee yield (600-1700 Kg ha-1.). The fourth study utilized climatic data from Coordinated Regional Climate Downscaling Experiment under Representative Concentration Pathway 4.5 to evaluate the potential of cutting, seed and grafted seedlings in attenuating the effects of climatic conditions using Dynamic Agroforestry Coffee model. During the Near-term period (2026-2056) rainfall will increase in Kilimanjaro region at the range of 0.2-13 % while in Arusha region the increase will be 6.05-13 %. Minimum temperature is expected to increase at higher rate than maximum temperature at the range of 1.4-1.48 °C in Kilimanjaro region and in Arusha region at the range of 1.36-1.64 oC. The use of cutting, seed and grafted propagated coffee plants when combined with FYM will result into 40% 35 % and 10% yield reduction respectively. Specific Leaf Area (SLA) among the three types of seedlings also varied; 28 (cutting), 19 (Seed) and 9 (grafted). Higher SLA observed in cutting-propagated plants may affect coffee production since it is linked to high loss of water in plants. Future higher yield loss was observed with the use of inorganic fertilizer (38%) than FYM (18%) in all the three types of seedlings. Based on the above results, it can be concluded that during the last 40 years, coffee farmers from the Northern and Southern Highlands zone of Tanzania have experienced increase in temperature and decrease in rainfall. Rise in minimum temperature and decline in long rains has significantly affected coffee production in the Northern Highlands zone. Similar to the historical period, minimum temperature is expected to increase at the higher rate than maximum temperature in the Northern Highlands zone during the Near-term period. Integrated nutrients sources are able to provide sufficient nutrients to the three types of seedlings as the recommended rates of inorganic fertilizer. Yield of cutting propagated plants under the age of four years if established at the same time with seeds and grafted propagated plants is significantly higher than that of its counterpart. However, grafted propagated plants are more resilient to climate change. It is therefore recommended that, integrated soil fertility management (37.5 g N.P.K +10 Kg FYM) tree-1 to be used as one of the adaptation strategies because apart from providing nutrients to the coffee plants the package also helps in improving water retention properties of the soil. In addition, seedling distribution should be location specific, with cuttings-propagated plants being distributed in areas with rainfall above 1200 mm year-1. The findings hold significant policy implications for enhancing coffee production in regions affected by climate change. Policymakers should enhance timely and accurate weather information delivery along with developing institutions responsible for education and extension services provision. Multiplication and adoption of improved coffee varieties has to be enhanced and promoted by the policymaker. By promoting adoption of improved coffee varieties policymakers can enhance farmers' adaptive capacity and reduce the vulnerability of coffee production to climate-related risks. Future studies will focus on monitoring the response of three types of seedlings above the age of four years assuming that at a later age coffee tree will have reached its maximum production and so more nutrients and water will be required.