Browsing by Author "Mourice, S. K."
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Item Integrated assessment of climate change impacts and adaptation in agriculture: the case study of the Wami River Sub-basin, Tanzania(Springer Nature Switzerland AG, 2020) Tumbo, S. D.; Mutabazi, K. D.; Mourice, S. K.; Msongaleli, B. M.; Wambura, F. J.; Mzirai, O. B.; Kadigi, I. L.; Kahimba, F. C.; Mlonganile, P.; Ngongolo, H. K.; Sangalugembe, C.; Rao, K. P. C.; Valdivia, R. O.This study evaluates the impacts of climate change and an adaptation strategy on agricul- ture in the Wami River sub-basin in Tanzania. This study uses the Agricultural Model Improvement and Inter-comparison Project (AgMIP) framework that integrates climate, crops and economic models and data using a novel multi-model approach for impact assess- ment of agricultural systems under current and future conditions. This study uses five Global Circulation Models (GCMs) from the fifth phase of the Coupled Model Inter-comparison Project (CMIP5), two crop simulation models, and one economic impact assessment model. In this study, a representative agricultural path- ways (RAP) that characterises future condi- tions following ‘business-as-usual’ trends was developed and used to model future agricul- tural systems in the Wami River sub-basin. Results show that by mid-century, the maxi- mum and minimum temperatures will increase by 1.8–4.1 °C and 1.4–4.6 °C, respectively. Rainfall is predicted to be variable with some places projected to increase by 12%, while in other areas it is projected to decrease by 14– 28%. Maize yields under these conditions are projected to decrease by 5.3–40.7%. Results show that under current conditions, 50–60% of farm households are vulnerable to losses due to climate change. The impacts of climate change on poverty and per capita income are also projected to be negative. Under the current production system, poverty rates were pro- jected to increase by 0.8–15.3% and per-capita income to drop by 1.3–7.5%. Future socio-economic conditions and prices offset the negative impacts of climate change. Under future conditions, the proportion of households vulnerable to loss is estimated to range from 25 to 50%. Per-capita income and poverty rates are expected to improve under the future climate change conditions. Poverty rates would decrease between 1.9 and 11.2% and income per-capita would increase between 2.6 and 18.5%. The proposed future adaptation pack- age will further improve household liveli- hoods. This integrated assessment of climate change projections using the improved meth- ods and tools developed by AgMIP has con- tributed to a better understanding of climate change and adaptation impacts in a holistic manner.Item Maize cultivar specific parameters for decision support system for agrotechnology transfer system (DSSAT) application in Tanzania(2013) Mourice, S. K.; Rweyemamu, C. L.; Tumbo, S. D.; Amuri, N.In order to develop basis for tactical or strategic decision making towards agricultural productivity improvement in Tanzania, a new approach in which crop models could be used is required. Since most crop models have been developed elsewhere, their adaptation, improvement and/or use outside their domain of development requires a great deal of data for estimating model parameters to allow their use. Cultivar specific parameters for maize varieties in Tanzania have not been determined before and consequently, crop modelling approaches to address biophysical resource management challenges have not been effective. An overall objective of this study was to evaluate DSSAT (v4.5) Cropping System Model (CSM) using four adapted maize cultivars namely Stuka, Staha, TMV1 and Pioneer HB3253. The specific objectives were; to determine maize crop growth and development indices under optimum conditions, to estimate maize cultivar parameters, and to evaluate DSSAT CSM for simulating maize growth under varied nitrogen fertilizer management scenarios. The results indicate that maize cultivars did not differ significantly in terms of the number of days to anthesis, maturity, or grain weight except final aboveground biomass. Also there was no difference between variables with respect to growing seasons. The cultivar specific parameters obtained were within the range of published values in the literature. Model evaluation results indicate that using the estimated cultivar coefficients, the model simulated well the effects of varying nitrogen management as indicated by the agreement index (d-statistic) closer to unity. Also, the cultivar coefficients which are difficult to measure physically were sensitive to being varied indicating that the estimated values were reasonably good. Therefore, it can be conclude that model calibration and evaluation was satisfactory within the limits of test conditions, and that the model fitted with cultivar specific parameters that can be used in simulation studies for research, farm management or decision making.Item Modeling potential rain-fed maize productivity and yield gaps in the Wami river sub-basin, Tanzania(Acta Agriculturae Scandinavica, Section B — Soil & Plant Science, 2014-11-05) Mourice, S. K.; Tumbo, S. D.; Nyambilila, A; Rwehumbiza, C. L.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.Item Narrowing maize yield gaps under rain-fed conditions in Tanzania: effect of small nitrogen dose(2014) Mourice, S. K.; Rweyemamu, C. L.; Nyambilila, A.; Tumbo, S. D.The wide gap between potential and actual yields of maize in Tanzania, due low productivity is the major constraint to improvement of food security and livelihood of farmers. The objective of this study was to evaluate the potential of the use of small amount of nitrogen fertilizer as a measure to reduce maize yield gap under rain fed conditions. Field experiments were conducted at Sokoine University of Agriculture, Morogoro during the dry and rainy seasons of 2012/2013 using Maize cultivar PIONEER PHB 3253. The nitrogen application rateswere 0 (control), 15 (low N dose) and 80 kg N ha-1 (recommended rate). Three water application regimes were tested. Irrigation water was applied from crop establishment up to; grain filling; 50% anthesis; and between 50% anthesis and grain filling. The treatments were applied in a completely randomized block design, in factorial layout forthe dry season experiment. Nitrogen treatments were repeated during the 2012/2013 rain season under rain-fed conditions. Both experiments were replicated three times. In a dry season experiment, the water application regimes significantly (P≤0.05) increase biomass at both 50% and harvest maturity stages. Total tissue N content decreased under nonstressedwater regime relative to water-stressed treatments. The interaction between irrigation andnitrogen interaction significantly (P≤0.05) affected grain yield. Application of recommended N rate did not result into yield increase when water was limiting. In the rainy season experiment, the recommended Nrate resulted in highest biomass at end of juvenile (1 t ha-1), 50% anthesis (7.7 t ha-1) and harvest maturity stages (13.1 t ha- 1). Total tissue N content and grain yield increased significantly with increase in N application rates during the rainy season. Under water stress conditions, low N dose produced an extra 1000 kg ha-1 grain yield over absolute control treatment. Under water stress conditions, recommended N rate a 54% reduction of yield gap was observed, which could not sufficiently reduce yield gap. However, under adequate soil moisture conditions, recommended N rate attained up to 26% yield gap, suggesting that it would be beneficial to apply nitrogen fertilizer when water is not limiting to close the yield gap. Small nitrogen doses can be an effective strategy towards narrowing yield gaps for resource poor farmers especially in drought prone areas. Further study should be done to extend the results beyond experimental site to test and validate the approach under farmers’ paradigms.Item Performance of hermetic storage bags for maize grains under farmer- managed conditions: Good practice versus local reality(Elsevier Ltd, 2020) Kiobia, D.O.; Silayo, V. C. K.; Mutabazi, K. D.; Graef, F.; Mourice, S. K.There are various types of grain storage bags available to farmers in tropical countries. However, these bags differ in price, quality, and reduced post-harvest losses due to insect pests and mould infestation. This study aimed to compare the effectiveness of three types of storage bags of Purdue Improved Crop Storage (PICS), Grain pro-super (GPS) and woven (WN) bags under assumed small farmer’s storage practices in the sub-tropical climatic conditions. The practice of weekly routine opening of the bags was compared with the recommended practice of keeping the bags closed for at least 3 months. Under laboratory experiment, insect population, moisture content, grain humidity, and temperature were measured at the weekly intervals while under farmer’s setting, moisture content (%) of maize and percentage of insect damage were measured after 3 and 6 months of storage at the farmer’s homestead. Considering the routine weekly opening effect, the PICS bag kept a low grain humidity average (56.6%) compared to the Grain pro-super bag (64.2%) and Woven bag (71.5%). The PICS bag reduced the insect population to an average of zero (0.4) compared to GPS (6.5) and the WN (14.8). Under farmer’s conditions, the mean difference in the percentage of insect damage between the PICS and GPS were insignificant (P > 0.05) at both 3 and 6 months of storage, and the insect damage throughout decreased with time. The results of this study indicate that PICS bag may support positively the practice of routine weekly opening compared to the GPS and WN in the sub-tropical climatic conditions.Item Unmanned aerial vehicle-based remote sensing in monitoring smallholder, heterogeneous crop fields in Tanzania(International journal of remote sensing, 2018) Yonah, I. B.; Mourice, S. K.; Tumbo, S. D.; Mbilinyi, B. P.; Dempewolf, J.Obtaining information to characterize smallholder farm fields remains elusive and has undermined efforts to determine crop conditions for food security monitoring. We hypothesize that unmanned aerial vehicles (UAV) would provide high-resolution spectral signatures for effectively discerning agronomic and crop conditions, management practices, and yields in smallholder farms for crop yield outlooks. The current study explores potential in using UAV-mounted sensor spectral signatures for monitoring crop conditions in smallholder agriculture. Images were collected using a 4-band multispectral camera mounted on a small fixed wing UAV, flown at 8-day interval over maize–pigeonpea experimental plots at Sokoine University of Agriculture and maize monocrop in farmers’ fields nearby, during 2015/2016 growing season. Four spectral vegetation indices (VIs) namely; normalized difference vegetation index (NDVI), wide dynamic range vegetation index (WDRVI), red edge chlorophyll index (CIred-edge), and the green chlorophyll index (CIgreen), were evaluated under maize monocrop, maize pigeonpea-intercrop, fertilizer and non-fertilizer and two maize varieties conditions. VIs were used also to detect differences in farm management practices of two farmers’ maize fields. The response of the spectral VIs varied depending on phenological stage of the crop and imposed treatments or management practices. In experimental plots, NDVI was able to distinguish fertilized from non-fertilized plots at all times, distinguish between two maize varieties at 52 days after sowing (DAS), and differentiate monocropped maize from maize–pigeonpea intercrop at 60 DAS. CIred-edge could detect effect of maize–pigeonpea intercrop and maize varieties at 44 DAS, whereas CIgreen could detect variety differences at 44 DAS, intercropping effect at all times and fertilizer effects at 60 and 68 DAS. WDRVI could only detect variety differences and maize–pigeonpea intercrop at 44 DAS. Moreover, NDVI was slightly associated with maize yield in non-fertilized plots (coefficient of determination – R2 = 0.58) and CIgreen was associated with leaf area index (LAI) (R2 = 0.62) in fertilized plots and in monocropped plots (R2 = 0.61). CIgreen could also differentiate well managed from poorly managed farmer’s fields. We conclude that UAV-derived spectral signatures can provide detailed information for characterizing agronomic and crop conditions under smallholder agricultural settings and aid food security monitoring efforts.