Browsing by Author "Kimaro, A.A"

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Competition between maize and pigeonpea in semi-arid Tanzania: effect on yields And nutrition of crops
(Elservier, 2009) Kimaro, A.A; Timmer, V.R.; Chamshama, S.A.O; Ngaga, Y.N; Kimaro, D.A
Productivity of maize–pigeonpea cropping systems is dependent on facilitative and competitive interactive effects on resource availability. Controlling these interactions may benefit farmers through increased productivity associated with optimized crop yields. Previous research on maize–pigeonpea culture in Sub-Saharan Africa has focused on yield and soil fertility, but provided inadequate information on the mechanisms of possible interspecific competition. We employed a factorial field experiment to examine yield and nutritional responses of maize and pigeonpea to cropping systems (sole maize, intercropping, and improved fallow), N and P fertilizer additions, and cattle manure additions in Dodoma, Tanzania. The study objectives were to assess competition between crops and to determine how manure or fertilizer inputs may mitigate such interactions to improve yields. Intercropping enhanced maize yield over sole maize only when fertilized, reflecting probable nutrient competition. Improved fallows alone or with fertilizers (1.2–1.6 Mg ha 1 ) increased maize yields over sole maize (0.6 Mg ha 1 ). These increases were attributed to pigeonpea facilitation through soil nutrient replenishment, reduced competition associated with sequential cropping arrangements, and added nutrients from fertilization. Combined fertilizer and manure applications also improved maize and pigeonpea yields. Plant nutrient diagnosis indicated primary and secondary P and Ca deficiencies, respectively associated with P-fixation and leaching of cations due to high soil acidity and exchangeable Al. Maize competed strongly in mixture suppressing biomass and grain yields of the unfertilized pigeonpea by 60% and 33%, respectively due to limited soil nutrients and/or moisture. These yield reductions suggest that the intercropped pigeonpea did not recover from competition after maize harvesting that reduced competition. Optimizing yields of both maize and pigeonpea would require the addition of prescribed fertilizer when intercropped, but applications can be reduced by half under the improved fallow system due to alleviating interspecific competition.
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.
Nitrogen and Phosphorus Fertilizer Micro-doses on Maize and Its Effect on P-foriability: An evidence from Sub-humid Farming Systems, Tanzania
(ournal of Economics, Management and Trade, 2018) Saidia, P.S; Graef, F; Rweyemamu, C.L; Kahimba, F.C; Semoka, J.M.R; Kimaro, A.A; Mwinuka, L; Mutabazi, K.D; Sieber, S
Despite a high productive potential for many best bet agricultural technologies, there is a low rate of adoption from farmers. Recommendations of improved technologies such as fertilizer use based on agronomic data without economic analysis contributes to this low adoption rate. The purpose of this study was to evaluate the profitability of selected fertilizer types and rates in maize production in a sub-humid farming system. A field experiment was conducted to investigate costs and revenue of fertilizer types and rates applied on maize farms using a split-plot layout under randomized complete block design. The phosphate fertilizers trialed were local Minjingu Mazao (MM), diammonium phosphate (DAP) and triple super phosphate (TSP), urea was used to supply nitrogen. Fertilizer rates were micro-doses at 12.5%, 25%, 50% and 75% compared to control and recommended rates. Local MM at 75% micro-dosing produced the highest net benefit 3.0 – 3.5 million Tanzanian Shillings per hectare (TZS/ha) followed by 2.7 – 2.9 million TZS/ha from TSP at recommended rates and DAP at a 75% micro-dose rate under subsistence farming. Micro-dosing fertilizer at 25% and 50% produced the highest benefit-cost ratio under both commercial and subsistence farming conditions. Micro-dosing at a rate of 12.5% was more profitable than the control rate and farm profitability increased towards 25% and 50%, thereafter decreasing as application approached the recommended rate. Adoption of micro-dosing fertilizer at 12.5% could be an entry point to fertilizer use and to later be advanced to 25% and 50% micro-dosing rates which are more profitable under smallholder farming systems in sub-humid tropics.
Soil moisture management and fertilizer micro-dosing on yield and land utilization efficiency of inter-cropping maize-pigeon-pea in sub humid Tanzania
(Elsevier, 2019-07) Saidia, P.S; Rweyemamu, C.L; Semoka, J.M.R; Kimaro, A.A; Germer, J; Asch, F; Kahimba, F.C; Graef, F; Lagweni, P.P
Principally caused by soil water stress and declining soil fertility, low crop productivity results in both food and income insecurity. The eﬀects of nitrogen and phosphorus fertilizer micro-dosing with inter-row rainwater harvesting practices for maize and pigeon-pea inter-cropping on yield and land use efciency are inadequately documented in sub humid tropics. A feld experiment on sandy loam soils in sub humid conditions using a splitsplit plot design was conducted. Plots used in situ rainwater harvesting practices of tied ridges, open ridges, and ﬂat cultivation. Sub-plots were sole maize, sole pigeon-pea, and 1:1 maize-pigeon pea inter-cropping. The subsub plots were control, fertilizer (N and P) application at the micro-dose level, and recommended rates. Tied ridges signifcantly (p < 0.001) conserved more soil moisture than ﬂat cultivation at 30 cm depth after ten days of rainfall. Ridges increased maize yield by 0.3 t ha−1 over ﬂat cultivation. Fertilizer application signifcantly (p < 0.001) increased maize yield by 1.12 t ha−1 with micro-dosing and by 1.60 t ha−1 with recommended rates over the control. Combining tied ridges and fertilizer signifcantly (p < 0.040) increased maize yield by 132–156% compared to ﬂat cultivation without fertilizer. Reﬂecting a land equivalent ratio, land use efciency was 67–122% higher in inter-cropping than sole crop. Tied ridges conserved more soil moisture than ﬂat cultivation, enhancing fertilizer use efciency that improved crop yields and land equivalent ratio under intercropping. This strategy could increase food availability and income generation under smallholder farming systems in sub-humid tropic areas.