Browsing by Author "Mourice, Sixbert Kajumula"

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Long-term spatial-temporal trends and variability of rainfall over Eastern and Southern Africa
(Springer, 2019) Muthoni, Francis Kamau; Odongo, Vincent Omondi; Ochieng, Justus; Mugalavai, Edward M; Mourice, Sixbert Kajumula; Hoesche-Zeledon, Irmgard; Mwila, Mulundu; Bekunda, Mateete
This study investigates the spatial-temporal trends and variability of rainfall within East and South Africa (ESA) region. The newly available Climate Hazards group Infrared Precipitation with Stations (CHIRPS-v2) gridded data spanning 37 years (1981 to 2017) was validated against gauge observations (N = 4243) and utilised to map zones experiencing significant monotonic rainfall trends. Standardised annual rainfall anomalies revealed the spatial-temporal distribution of below and above normal rains that are associated with droughts and floods respectively. Results showed that CHIRPS-v2 data had a satisfactory skill to estimate monthly rainfall with Kling-Gupta efficiency (KGE = 0.68 and a high temporal agreement (r = 0.73) while also preserving total amount (β = 0.99) and variability (γ = 0.8). Two contiguous zones with significant increase in annual rainfall (3–15 mm year−1 ) occurred in Southwest Zambia and in Northern Lake Victoria Basin between Kenya and Uganda. The most significant decrease in annual rainfall (− 20 mm year−1 ) was recorded at Mount Kilimanjaro in Tanzania. Other significant decreases in annual rainfall ranging between − 4 and − 10 mm year−1 were observed in Southwest Tanzania, Central-South Kenya, Central Uganda and Western Rwanda. CHIRPS-v2 rainfall product provides reliable high spatial resolution information on amount of rainfall that can complement sparse rain gauge network in rain-fed agricultural systems in ESA region. The observed spatial-temporal trends and variability in rainfall are important basis for guiding targeting of appropriate adaptive measures across multiple sectors.
Modeling potential rain-fed maize productivity and yield gaps in the Wami river sub-basin, Tanzania
(Taylor And Francis Journals, 2015) Mourice, Sixbert Kajumula; Tumbo, Siza Donald; Amuri, Nyambilila; Rweyemamu, Cornell Lawrence
The cause for low maize yields in rain-fed production systems is usually associated with water stress due to perceived suboptimal seasonal precipitation. A modeling study using Agricultural Model Intercomparison and Improvement Project modeling framework was conducted to determine the magnitude of rain-fed potential yield and yield gap of maize in the Wami River sub-basin, Tanzania. Primary and secondary data on soils, weather, management, and crop yields and cultivars were used. Data matrix search technique was used to calibrate CERES-Maize Crop System model against reported yield for each of 168 farms involved in this study. Then the individual farms’ simulated yields, actual reported yields, and the resultant yield gaps were aggregated into ward-level averages. Model calibration was robust as there was a very close agreement between reported and simulated yield (R2 = 0.9). Actual yields reported from farm survey ranged from 50 kg ha−1 to 3600 kg ha−1 with an average of 860 kg ha−1 . Simulated rain-fed potential yield was between 2073 kg ha−1 and 5443 kg ha−1 and a mean of 4033 kg ha−1 . It is apparent therefore that there exists a wide maize yield gap of 79% with current management under rain-fed conditions. This suggests that there is a large scope of improving maize yields under rain-fed conditions. Narrowing the yield gaps would require an intensive soil fertility improvement in the study area.
Screening coalmon bean (Phaseolus Vulgaris L. Savi) genotypes adapted to low soil phosphorus
(Sokoine University of Agriculture, 2006) Mourice, Sixbert Kajumula
Two screen house pot experiments were conducted to identify bean genotypes, diverse in their places of origin and seed size, based on vegetative growth and P uptake and final grain yield for adaptation to low phosphorus. Three phosphorus levels; low P (0 added P), medium P (40 mg P/kg soil) and high P (160 mg P/kg soil) were main plots whereas 27 genotypes were subplots, in a split-plot laid out in a completely randomised design. The test soil was very fine, kaolinitic Kanhaplic H0aplustult. Out of 27, seven bean genotypes were further evaluated for yield components and final grain yield at low P in the same soil. Shoot biomass, root biomass, shoot P concentration and P uptake increased with increased P supply and genotypic variability in these parameters was significant (P < 0.05). Genotypes G92, PRETO 143, MILENIO, VEF 88(40), BAT 477, A785, ANT 22, DOR 714 and AFR 708 performed better than other genotypes at low P level; also their response to P addition was significant. It was revealed that P was a major limiting factor to bean growth in the soil used for the experiment. Number of pods/plant increased significantly with increase in P levels and was correlated with grain yield at low P and adequate P. P treatments did not affect the seed size of genotypes. Genotypes BAT 477, MILENIO, DOR 714 and A785 had significantly higher grain yield than other genotypes at low P and may be favoured in the selection process. Although genotypes produced some grain yield at low P, soil fertility improvement by applying medium P or appreciable amounts of organic manure may improve yields and increase productivity per unit area.
Screening coalmon bean [Phaseolus vulgaris l. savi] genotypes adapted to low soil phosphorus
(Sokoine University of Agriculture, 2006) Mourice, Sixbert Kajumula
Two screen house pot experiments were conducted to identify bean genotypes, diverse in their places of origin and seed size, based on vegetative growth and P uptake and final grain yield for adaptation to low phosphorus. Three phosphorus levels; low P (0 added P), medium P (40 mg P/kg soil) and high P (160 mg P/kg soil) were main plots whereas 27 genotypes were subplots, in a split-plot laid out in a completely randomised design. The test soil was very fine, kaolinitic Kanhaplic I-Iaplustult. Out of 27, seven bean genotypes were further evaluated for yield components and final grain yield at low P in the same soil. Shoot biomass, root biomass, shoot P concentration and P uptake increased with increased P supply and genotypic variability in these parameters was significant (P < 0.05). Genotypes G92, PRETO 143, MILENIO, VEF 88(40), BAT 477, A785, ANT 22, DOR 714 and AFR 708 performed better than other genotypes at low P level; also their response to P addition was significant. It was revealed that P was a major limiting factor to bean growth in the soil used for the experiment. Number of pods/plant increased significantly with increase in P levels and was correlated with grain yield at low P and adequate P. P treatments did not affect the seed size of genotypes. Genotypes BAT 477, MILENIO, DOR 714 and A785 had significantly higher grain yield than other genotypes at low P and may be favoured in the selection process. Although genotypes produced some grain yield at low P, soil fertility improvement by applying medium P or appreciable amounts of organic manure may improve yields and increase productivity per unit area.