Soil Fertility Status of Kagera Region and the “Organic-by-Default” Coffee Paradigm: A Meta-Analysis of Existing Database

Maro G.P.^1, , Ng’homa N.M.², Mbwambo S.G.¹, Monyo H.E.¹ and Mosi E.J.¹

¹TaCRI Lyamungu Soil Fertility Laboratory, P.O. Box 3004 Moshi, TANZANIA

²TaCRI Maruku, Bukoba, TANZANIA

Cite this paper:
Maro G.P., Ng’homa N.M., Mbwambo S.G., Monyo H.E. and Mosi E.J.. Soil Fertility Status of Kagera Region and the “Organic-by-Default” Coffee Paradigm: A Meta-Analysis of Existing Database. World Journal of Agricultural Research. 2024; 12(1):1-7. doi: 10.12691/wjar-12-1-1

Abstract

Coffee farmers in Kagera Region do not believe in application of industrial fertilizers in their farms, calling their produce “organic by default”. They claim that their soils are too fertile to need industrial fertilizers. TaCRI undertook to verify this claim. Soil fertility data for the region were extracted from the national coffee soil database built in 2015. A total of 73 georeferenced sites had seven parameters (pH, Ca, Mg, K, CEC, OC and total N) rated from zero (poor) to 4 (good). The average ratings were computed and categorized as 0-1, 1-2, 2-3, 3-4 and 4-5 as poor, marginal, moderate, satisfactory and good fertility respectively. A subsample of 27 sites were additionally assessed for available P and particle size. Attributes of the 73 sites were loaded into ArcMap 10.7.1, whereby pH, CEC, BS, OC and C:N ratio were interpolated using the IDW algorithm and clipped on basis of the regional boundary shapefile extracted from the 2022 census polygon shapefile. The soils were marginally (34, 47%) to moderately (39, 53%) fertile where only seven parameters were assessed. With fewer sites and more parameters, the respective figures were 11 (41%) and 16 (59%). pH was increasing from northeast (Bukoba, Misenyi and Muleba) to southwest (Biharamulo, Ngara and Southern Karagwe). CEC was lower in Kyerwa, Karagwe and Muleba than Bukoba, Ngara and Biharamulo. The western half of Kagera had higher OC than its eastern counterpart. C:N ratios were generally less than 30, which is normal. This work has revealed that soils in Kagera are not as fertile as purported, thus disproving the “organic-by-default” paradigm. As such, farmers’ mind sets should be changed in favour of industrial fertilizers if we are ever to improve coffee productivity and approach the set national target of producing 300,000 metric tons of clean coffee annually by 2025/26.

Keywords:
soil fertility organic by default meta-analysis database Kagera region

This work is licensed under a Creative Commons Attribution 4.0 International License. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/

References:

[1]	Carr, M. K.V., Stephens, W., Van der Vossen, H.A.M. and Nyanga, A. (2003). Tanzania Coffee Research Institute: Strategic Action Plan 2003 to 2008, Contributing Towards a Profitable and Sustainable Coffee Industry in Tanzania. International Centre for Plant Sciences, Cranfield University, Silsoe, UK. 142pp.
[2]	Baffes, J. (2003). Tanzania Coffee Sector: Constraints and challenges in Global environment. The World Bank, Washington, DC. 56pp.
[3]	Hella, J.P., Mdoe, N.S. and Lugole, J.S. (2005). Coffee Baseline Report for Tanzania Coffee Research Institute.Bureau for Agricultural Consultancy and Advisory Service, Sokoine University of Agriculture, Morogoro, Tanzania. 40pp.
[4]	Tanzania Coffee Board (2020). Tanzania Coffee Industry Development Strategy 2020/2025. Government Document, Moshi, Tanzania. 57pp.
[5]	Montagnon, C. and Brouwers, S. (2013). Strategic Action Plan III and Strategic Business Plan 2013-2018 for Tanzania Coffee Research Institute (TaCRI). RD2 Vision/Efficient Innovations, March 2013, 102pp.
[6]	Mbwambo, S.G., Maro, G.P., Monyo, H.E. and Mosi, E.J. (2020). Towards expansion of Coffea canephora production in Tanzania: The land suitability perspective. World Journal of Agricultural Research Vol 8 (2), May 2020: 52-56
[7]	Mbogoni, J.D.J. and Nyaki, A.S. (2006). GIS database for the lower Kagera River basin in Tanzania. Diagnostic study report for the Tanzanian component of the TAMP Programme. March, 2006: 64pp.
[8]	Cordingley, J. (2010). Soil Fertility Survey of Tanzania’s Smallholder Coffee Sector for Developing Lime and Fertilizer Recommendations. Report to Tanzania Coffee Board. Crop Nutrition Laboratory Services, Nairobi, Kenya. 60pp.
[9]	Maro, G. P., Mbwambo, S.G., Monyo, H.E., Nkya, E.O. and Mosi, E.J. (2018). Generating soil fertility database for coffee growing areas in Tanzania. Proc. 6th Annual National STI Conference and Exhibitions, COSTECH, 4-6 July 2018, Mlimani City, Dar es Salaam.
[10]	National Bureau of Statistics (2018). Kagera Region socio-economic profile 2015. Government Document, Dar es Salaam, April 2018: 243pp.
[11]	Howard, A.E. (2011). A brief introduction to the geology and mining industry of Tanzania. SIKA Resources Inc, Toronto, Ontario, Canada, October, 2011: 15 pp.
[12]	Lupogo, K. (2013). A review of engineering geology in Tanzania. International Journal of Research in Engineering and Science Vol 1 Issue 8, December 2013:48-55.
[13]	Mlingano Agricultural Research Institute (2006). Soils of Tanzania and their potential for agriculture development. A MAFSC-DRT Report, November, 2006. 33pp.
[14]	Maro, G.P. (2013). Soil fertility report for coffee growing districts in Kagera Region. Soil Survey Report TCR 8/1013, Coffee Soil Database Project (TASP I), February 2013: 47pp.
[15]	Sys, C., Van Ranst, E. and Debaveye, J. (1993). Land Evaluation Part III Crop Requirements. General Administration for Development Cooperation, Agriculture Publications, Brussels, Belgium. 199pp.
[16]	Thiagalingam, K. (2000). Soil and plant sample collection, preparation and interpretation of chemical analysis: A training manual and guide. ACNARS/PNG for AusAID, Adelaide, Australia. 49pp.
[17]	Hamza, M.A. (2008). Understanding soil analysis data. Resource management technical report 327, Department of Agriculture and Food, Western Australia. 59pp.
[18]	Kyariga, A.T. (2001). GIS as a decision-making support tool for urban planning and management: A practical case of Tanzania. CORP2001, Vienna University of Technology:101-106.
[19]	National Bureau of Statistics (2020). The population census map of Tanzania at ward level. Online GIS database, National Bureau of Statistics, Dar es Salaam, Tanzania.
[20]	Altaweel, M. (2022). GIS and spatial interpolation methods. Spatial Analysis, GIS Lounge, October 2022. gislounge.com/gis-spatial-interpolation-methods/ accessed 06 April, 2023
[21]	Wu, X.H. and Hung, M.C (2016). Comparison of spatial interpolation techniques using visualization and quantitative assessment. In: Hung, M.C. (Ed), Applications of spatial statistics. Nov, 2016.
[22]	Uchida R. and Hue, N.V. (2000). Soil acidity and liming. In: Silva, J.A. and Uchida, R. (eds): Plant nutrient management in Hawaiian soils: Approaches for tropical and subtropical agriculture. CTAHR, University of Hawaii at Manoa. Pp. 101-112.
[23]	Hofman, G. and Salomez, J. (2004). Chemical soil fertility management: Partim Fertility Management. Lecture notes, Fac. Agric & Appl. Biol. Sci., Ghent University. 55pp.
[24]	Van Ranst, E. (1997). Tropical soils: Geography, classification, properties and management. Lecture notes. International Centre for Physical Land Resources. Lab. of Soil Sci., Ghent University, Belgium.310pp.
[25]	Tumuhairwe, J. B., Rwakaikara-Silver, M.C., Muwanga, S. and Natigo, S. (2007). Screening Legume Green Manure for Climatic Adaptability and Farmer Acceptance in the Semi-Arid Agro-Ecological Zone of Uganda. In: Advances in ISFM in Sub-Saharan Africa: Challenges and opportunities. (Edited by Batiano, A.),Springer, Amsterdam, The Netherlands: pp. 255 – 259.
[26]	Ngeze, P. B. (2015). Kahawa Tanzania. Tanzania Educational Publishers Ltd, Bukoba, Tanzania. 286pp
[27]	Maro, G. P., Monyo, H.E., Nkya, E.O. and Teri, J. M. (2006). The soil fertility status of coffee growing areas in Tanzania. In: Proceedings of the 21st ASIC Conference, 9– 14 September 2006, Montpellier Cedex, France. pp. 1419 – 1422.
[28]	Maro, G.P., Teri, J.M., Magina, F.L. and Nkya, E.O. (2012). Effects of shade on yields of selected improved hybrid Coffea Arabica varieties in Tanzania. Proc. ASIC 24, San Jose, Costa Rica, 11-17 November, 2012: 1203-1207.
[29]	Oberthur, T., Pohlan, J. and Soto, G. (2012). Plant Nutrition Sustainable Nutrient Management. In: Oberthur, T. et al. (Eds.), Specialty coffee managing quality. International Plant Nutrition Institute, South Eastern Asia Programme, Penang, Malaysia.149pp.
[30]	Wairegi, L., Van Asten, P., Giller, K.E. and Fairhurst, T. (2014). Banana coffee system cropping guide. African Soil Health Consortium, Nairobi, Kenya: 121pp.
[31]	Van der Vossen, H.A.M. (2005). A critical analysis of the agronomic and economic sustainability of organic coffee production. Experimental Agriculture 41: 449 – 473.
[32]	Valkila, J. (2009). "Fair Trade Organic Coffee Prouduction in Nicargagua -- Sustainable Development or a Poverty Trap?" Ecological Economics 68.12 (2009): 3018-025. Academic Search Complete. Web. 15 Nov. 2011.
[33]	Tanzania Coffee Research Insitute (2018a). “Kanuni za kilimo bora kwa kahawa ya Arabika” (GAPs for Arabica coffee), 2nd Edition, TaCRI, June, 2018: 110pp.
[34]	Tanzania Coffee Research Insitute (2018b). “Kanuni za kilimo bora kwa kahawa ya Robusta” (GAPs for Robusta coffee). TaCRI, December, 2018: 87pp.
[35]	Wrigley, G. (1988). Coffee: Tropical Agriculture Series. Longman Scientific and Technical, John Wiley and Sons Inc., New York, USA. pp.1 – 60.
[36]	Wintgens, J.N. (2012). Coffee: Growing, Processing, Sustainable Production: A Guidebook for Growers, Processors, Traders, and Researchers. Wiley VCH, Weinheim, Germany. 1022pp.