Browsing by Author "Kahimba, F"

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Combined effects of biochar and fertilizer application on maize production in dependence on the cultivation method in a sub-humid climate
(Taylor and Francis, 2018) Graef, H; Kiobia, D; Saidia, P; Kahimba, F; Graef, F; Eichler-Lobermann, B
Low, erratic rainfall amounts and restricted accessibility of chemical fertilizer for rural farmers in developing countries may have negative effects on crop production. Agricultural methods like biochar applications, fertilizer microdosing and tied ridging can help to mitigate these constraints, but have rarely been studied in combination and under varying water availability. A field trial was conducted in split-plot design over two contrasting cropping seasons in 2016 and 2017 in Tanzania to study the effect of these agricultural methods on maize grain yield, biomass, leaf area index, plant height and soil moisture content. In both seasons each with contrasting irrigation frequencies, fertilizer microdosing increased the grain yield of maize. Biochar alone affected the yield only at high application rates (10 t/ha) and low irrigation frequency. However, when combined with fertilizer microdosing the yield effect of biochar was more pronounced. For example, combining 5 t/ha biochar with fertilizer microdosing under flat tillage increased yield by 170% compared to the control without biochar and fertilizers. Tied ridges increased soil moisture content and tended to increase maize yield compared to flat tillage, whereas biochar application resulted in significantly higher soil moisture contents. Fertilizer microdosing with biochar application can be recommended to improve maize yields mainly under flat tillage.
Effects of Nitrogen and Phosphorus Micro-Doses on Maize Growth and Yield in a Sub-Humid Tropical Climate
(2018) Saidia, P.S; Rweyemamu, C.L; Asch, F; Semoka, J.M.R; Kimaro, A.A; Germer, J; Graef, F; Lagweni, P; Kahimba, F; Chilagane, E.A
Inadequate knowledge on fertilizer usage and poor financial resources are among the reasons for low maize productivity under small-scale farming. Fertilizer micro-dosing may increase food production by using low rates which are affordable by most resource poor farmers and have a high investment return. A two-year field experiment was conducted on sandy loam and sandy clay soils being typical representatives of sub-humid tropical agroecological zones. A split-plot design involved di-ammonium phosphate (DAP), Minjingu mazao (MM) and triple super phosphate (TSP) as main plots and fertilizer micro-dose rates of 10 kg N and 5 kg P/ha, 20 kg N and 10 kg P/ha, 40 kg N and 20 kg P/ha, 60 kg N and 30 kg P/ha, recommended rate 80 kg N and 40 kg P ha-1 and control as sub-plots. Phosphate fertilizers that produced highest grain yield were MM (2317 kg/ha), followed by DAP (2173 kg/ha) and TSP (2115 kg/ha). Fertilizer micro dose rates (10 kg N and 5 kg P/ha; 20 kg N and 10 kg P/ha) increased the yield by 90.5 and 136.6% from 1012 kg/ha in control, respectively. Intermediate rates (40 kg N and 20 kg P/ha) and (60 kg N and 30 kg P/ha) produced average grain yields of 2629 and 2647 kg/ha while the recommended rate produced 2601 kg/ha. The highest grain yield was 3910 kg/ha from MM at 40 kg N and 20 kg P/ha. Considering the micro-dose options therefore, MM fertilizer and micro dose rates (10 kg N and 5 kg P/ha) and (20 kg N and 20 kg P/ha) are recommended in these agro-ecological zones.
The ‘Majaluba’ rice production system: A rainwater harvesting ‘Bright Spot’ in Tanzania
(2018) Gowing, J; Bunclark, L; Mahoo, H; Kahimba, F
The rainwater harvesting technique under consideration here is an example of intermediate-scale external catchment runoff harvesting. The focus for discussion is on the ‘majaluba’ system which is found in Tanzania and comprises a network of roughly level basins each surrounded by an earth bund. Basins are arranged in the landscape in order to collect local runoff from stony outcrops and grazing lands in upslope areas with cattle tracks often used as conduits. The ‘majaluba’ system is used primarily for the production of rainfed lowland rice. It has spread through autonomous diffusion of knowledge from farmer to farmer since its introduction in the 1930s. The estimated extent of this system is around 600,000 ha which contributes 60% of total rice production in Tanzania. This is a remarkable, but little known, success story, and represents a water harvesting ‘bright spot,’ where sustainable intensification of smallholder agriculture has been achieved at scale.