by Godsteven Maro, Suzana Mbwambo, Deusdedit Kilambo and Leonard Kiwelu
Review Article
Soil fertility decline in coffee growing areas of Tanzania has been noted as one important limitation to coffee production, thus calling for appropriate remedial measures. This paper reviews soil fertility and its management, with a focus on integrated soil fertility management for coffee in the country. As a general rule, ISFM takes proper germplasm material as one of its tiers. With coffee in Tanzania however, this tier is removed from the sequence following the release and promotion of the 19 improved Arabica coffee varieties and 4 of Robusta, which are considered perfect. A 7-tier sequence is suggested. The first three tiers (terrain management, choice of shade trees and intercropping patterns) are concerned with field establishment and are more or less permanent, while the other four (green manuring, application of manures/composts, strategic application of reduced doses of inorganic fertilizers and soil amelioration) are related to routine management, and can swap between seasons depending on the farmer’s resource endowment. The whole idea is to always have accumulation of organic matter in the soil, which mineralizes slowly to release nutrients for plant use. Tanzania Coffee Research Institute (TaCRI) will continue research on ISFM and its promotion to its stakeholders through community-based organizations such as AMCOS. Formal and indigenous knowledge systems must become better integrated to allow farmer associations to recognize, adapt, and implement ISFM practices.
World Journal of Agricultural Research. 2024, 12(1), 8-17. DOI: 10.12691/wjar-12-1-2
Pub. Date: April 08, 2024
by Maro G.P., Ng’homa N.M., Mbwambo S.G., Monyo H.E. and Mosi E.J.
Original Research
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.
World Journal of Agricultural Research. 2024, 12(1), 1-7. DOI: 10.12691/wjar-12-1-1
Pub. Date: March 26, 2024