I am a cropping Systems Agronomist with 32 years of professional experience in Rice Research and Development in Ghana and West Africa. I have expertise in Rice Agronomy, Integrated soil fertility management, rice variety development, seed systems research and Participatory technology development and dissemination. My research focus has been the development and promotion of rice based cropping systems (eg the cowpea rice system, mucuna rice system and calopogonium rice systems). In recent time I have been coordinating research into Direct mulch based Cropping Systems (No till Agriculture) for rice, maize and soybean as a smart adaptation to the effects of Climate change in Northern Ghana and for soil fertility restoration using Stylosanthes, Crotolaria, Brachiaria and Centrocema. I have a lot of experience in rice variety development and rice seed systems and have spearheaded the release of 6 rice varieties. Through my efforts in rice seed systems development access of Seed Producers to quality foundation seed of rice rose from a little below 10 tons in 2013 to more than 45 tons in 2017. I have led Rice R
The yield of lowland paddy rice (Oryza sativa L.) is sensitive to water application regimes, whic... more The yield of lowland paddy rice (Oryza sativa L.) is sensitive to water application regimes, which can be affected by irrigation management. This study assessed the impacts of different irrigation applications on rice yield using the AquaCrop model. Experiments were conducted at two sites (On-station and On-farm) during the 2012/2013 and 2013/2014 dry seasons using five different irrigation treatments: field capacity (FC) moisture content (W 1 ), saturated soil moisture content (SC; W 2 ), continuous flooding (CF; W 3 ), 10ETc (crop water requirement) (W 4 ), and 15ETc (W 5 ). A 115-day rice variety, Gbewaa (Jasmine 85), was transplanted with a spacing of 20 cm × 20 cm for the experiments. The AquaCrop model was calibrated in terms of green canopy cover (CC), aboveground dry biomass, harvest index (HI), and paddy rice yield. The model was validated using various efficiency criteria (coefficient of determination, root mean square error (RMSE), RMSE–observations, standard deviation ra...
International Journal of Plant and Soil Science, 2021
The influence of zinc and sulfur on growth and yield of rice was studied for two soils; fallowed ... more The influence of zinc and sulfur on growth and yield of rice was studied for two soils; fallowed and continuously cropped. It was a 2 x 4 x 4 factorial experiment laid out in a randomized complete block design with three replicates, using lixisols of northern Ghana. Sulfur was applied as Sodium Sulfate (Na2SO4) at 0, 10, 20, 30 kg S/ha, two days after transplanting. Whilst zinc was applied as Zinc oxide (ZnO) at 0, 4, 8, 12 kg Zn/ha before transplanting. All soils received same rates of NPK (90-60-30 Kg/ha). An initial physico-chemical analysis conducted on the soils revealed that, both were sandy loam in texture and low in zinc but moderately high in sulfur. The fallowed soil was high in all other measured soil nutrients except nitrogen when compared to the cropped soil. The experimental results showed that, rice growth (tiller number, plant height), grain yield parameters (panicle count, percentage filled grains, grain yield) and straw yields are maximized by at least inclusion of...
International Journal of Agriculture Innovations and Research, 2015
An article published by International Journal of Agriculture Innovations and Research Volume 3, I... more An article published by International Journal of Agriculture Innovations and Research Volume 3, Issue 4, 2015
International Journal of Sciences: Basic and Applied Research, 2016
The upland field study was conducted during the 2014 major crop growing season under rainfed cond... more The upland field study was conducted during the 2014 major crop growing season under rainfed condition on a sandy loam soil (Ferric Acrisol) to compare the effect of different tillage practices and weeding frequency on yield parameters and yield of NERICA 4 rice variety at the Savannah Agricultural Research Institute of the Council for Scientific and Industrial Research, Nyankpala, Northern Region of Ghana. The experiment was arranged in a split plot design with three replications. The tillage treatments consisted of disc ploughing only, disc ploughing followed by disc harrowing, and no tillage as main plots and four weeding frequencies (weeding thrice, twice, once and no weeding) as sub-plots. The results indicated significant effects of tillage practices on the yield components and yield of NERICA 4. Disc ploughing followed by disc harrowing produced the highest number of panicles, panicle weight, number of spikelet's per panicle, dry matter yield, number of grains per panicle...
This paper underscores the influence of different fertilizers application on the growth, yield an... more This paper underscores the influence of different fertilizers application on the growth, yield and some trace elements uptake of two released local rice varieties widely cultivated and consumed in northern Ghana. Field experiments were conducted at the Council for Scientific and Industrial Research – Savanna Agricultural Research Institute at Nyankpala in the Northern Region of Ghana, to compare the performance of the rice varieties, viz . Digan and Nabogu. They were treated with three different inorganic fertilizers – NPK 15-15-15 (NPK), Sulphate of Ammonia (SA) and Triple Super Phosphate (TSP) and a control plot with no fertilizer treatment. The variety, Digan, showed shorter number of days (95) to 50% flowering than the Nabogu variety (107 days). The Digan variety yielded more under NPK and SA treatments than the Nabogu variety. The trace elements, Cd and Pb uptake by the two rice varieties were also assessed and found to be below detection limits. Fe and Mn were detected at an ...
Farmers’ participation in agricultural projects has a direct bearing on technology awareness, ado... more Farmers’ participation in agricultural projects has a direct bearing on technology awareness, adoption, livelihoods, environment, nutrition, poverty, performance of the agricultural sector and the macro economy. This study therefore sought to identify factors, which delimitate farmer’s participation in agricultural projects using the case of the Agricultural Value Chain Mentorship Project. A multi-stage sampling technique was employed to collect cross sectional data from 180 farmers in the Saboba and Chereponi districts of the Northern Region of Ghana. The study adopts the binary probit model and results of the analysis indicate that number of years in school, access to production credit and agricultural extension service are factors that significantly determine farmer’s participation in agricultural projects. It appears that farmer’s interest in agricultural projects can be permanently sustained by providing them with tangible benefits such as production credit and agricultural ext...
The major limiting factor for irrigated rice cultivation is water. As the demand for effective ma... more The major limiting factor for irrigated rice cultivation is water. As the demand for effective management of water increase due to climate change, future rice production will depend heavily on developing and adopting strategies and practices that use efficient water application. The objectives were to evaluate effects of different irrigation regimes on crop and economic water productivities as well as water balance for dry season irrigated rice production. This was to enable rice farmers and irrigation management to make an informed decision on the most economic and efficient water use regime for rice production. Two experiments were conducted using a randomized complete block design with 4 replications at On-Station (SARI) and On-Farm (Bontanga Irrigation Scheme) in 2012/2013 and 2013/2014 dry seasons. The treatments were, surface irrigation with applied water equal to: the Field Capacity (FC) moisture content ( W 1 ); Saturated soil moisture content (SC) ( W 2 ); Continuous floodi...
Abstract Increasing temperatures and water scarcity are concomitant threats to sustainable rice p... more Abstract Increasing temperatures and water scarcity are concomitant threats to sustainable rice production in future climates. Although both aspects have been widely studied, little is understood about how water-saving management might affect heat-induced stress and grain yield of rice under open-field conditions. The objective was to clarify how water management practices affect daily inner-canopy temperature (Tc) dynamics, flowering time, heat-induced spikelet sterility, and rice grain yield. Field experiments were conducted in four consecutive wet and dry seasons in northern Ghana. Two rice varieties, IR64 and Jasmine85, were grown under two water regimes: 1) continuous flooding (FL), and 2) continuous flooding except for an approximately 20-day drainage treatment at the flowering period (DF). Although the DF treatment was non-flooded, a high moisture content was maintained (>60 % of saturated volumetric water) to avoid any significant drought stress. The effect of water regimes on grain yield and Tc differed significantly between the dry season (DS) and wet season (WS). DF significantly reduced yields by 13–26 % in the DS but not in the WS. However, the effect of DF on Tc at flowering time (0.2–0.3 °C increase) and spikelet sterility (3–5% increase) was relatively small even in the DS. In contrast, DF greatly increased Tc from solar noon to midnight, in particular during the period of ±3 h from sunset in the DS. At this time of the day, DF had a higher Tc than FL by 0.7–0.9 °C on average. The Tc did not differ between DF and FL either at flowering time or nighttime in the WS. The Tc changes over the course of the day imply that water-saving management may have a higher risk of yield reduction in the DS of the sub-humid tropics not only by increasing heat-induced sterility but also by increasing late-afternoon-to-nighttime temperatures, which can cause physiological stress and respiration loss. These results can help improve water-saving management practices under contrasting climatic conditions in the sub-humid tropics and predict the combined effect of increasing temperatures and water scarcity on rice production.
If future rice production is to contribute to food security for the increasing population of sub-... more If future rice production is to contribute to food security for the increasing population of sub-Saharan Africa (SSA), effective strategies are needed to control weeds, the crop’s fiercest competitors for resources. To gain better insights into farmers’ access to, and use of, herbicides as part of weed control strategies, surveys were conducted in key rice production locations across SSA. Farm surveys were held among 1965 farmers across 20 countries to collect data on rice yields, farmer’s weed management practices, herbicide use, frequencies of interventions and information sources regarding herbicides. Markets were surveyed across 17 countries to collect data on herbicide availability, brand names and local prices (converted to US$ ha−1). Herbicides are used by 34% of the rice farmers in SSA, but adoption ranges from 0 to 72% across countries. Herbicides are more often used by men (40%) than by women (27%) and more often in irrigated (44% of farmers) than in rainfed lowland (36%) ...
Abstract Nutrient deficiencies are considered major constraints to rice production in sub-Saharan... more Abstract Nutrient deficiencies are considered major constraints to rice production in sub-Saharan Africa (SSA), but a systematic, continent-wide analysis of these constraints is lacking. The objective of this study was to assess responses of rice yields to macronutrients (N, P, and K) across major rice production systems [irrigated lowland rice (IL), rainfed lowland rice (RL), and rainfed upland rice (RU)] and diverse agro-ecological zones (semi-arid, sub-humid, humid, and highlands) in SSA. Diagnostic trials were conducted in 17 countries in 18–60 farmers' fields in each of 30 sites (totaling 1037 farmers' fields), of which 12 sites were in IL, 15 in RL and 3 in RU. All trials had an NPK treatment, and three treatments in which either nitrogen (N), phosphorus (P), or potassium (K) was omitted from the NPK treatment (minus N, P, and K plots). The trials were conducted during one or two seasons. Regression between yields in the NPK and minus N plots was used for calculating N fertilizer requirement, following the approach used for the development of a nutrient management decision support tool for rice (RiceAdvice) in SSA. Site mean yields in the NPK treatment ranged from 1.4 to 7.3 t ha−1. On average, these yields were 1.1 t ha−1 higher than farmers' yields previously observed in the same sites. N was generally the most limiting nutrient, followed by P. Rice yields without N, P, and K were 68, 84, and 89% of yields in the NPK treatment, and were positively correlated with those in the NPK treatment irrespective of production systems and agro-ecological zone (AEZ). Results from a regression model across sites indicated that achieving 3, 5, and 7 t ha−1 requires N fertilizer application at an average rate of 56, 91, and 122 kg N ha−1, respectively. However, there was significant treatment by site interaction on rice yield. Site mean yields were significantly lower without N, P, and K in 93, 60, and 50% of sites as compared to the NPK treatment. Yield response to macronutrients varied across sites and was not related to production system, nor AEZ. Results from this study will help further improvement of RiceAdvice for providing decision support tailored to the particular site, zone, or production system, thereby closing yield gaps, improving fertilizer nutrient efficiency and preventing negative environmental consequences of fertilizer use.
Rice (Oryza spp.) is the major staple food for most countries in West Africa, but local productio... more Rice (Oryza spp.) is the major staple food for most countries in West Africa, but local production does not meet demand. Rice is grown mainly by smallholder farmers, and yields are generally low with high temporal and spatial variability. Low yields have been attributed to unfavorable climate conditions, poor soil quality, and sub-optimum agricultural practices. The objectives of this study were to assess variation in yields of three major rice production systems (irrigated lowland, rainfed lowland, and upland) across three climatic zones (semi-arid, sub-humid, and humid), and identify factors affecting that variation. We analyzed data on yield, climate, soil, and agricultural practices for 1305 farmers’ fields at 22 sites in 11 West African countries between 2012 and 2014. A boundary function approach was used to determine attainable yields. Random forest algorithm was used to identify factors responsible for yield variation. Average rice yield was 4.1, 2.0, and 1.5 t ha−1 in irrigated lowland, rainfed lowland, and rainfed upland systems, respectively, with maximum attainable yields of 8.3, 6.5, and 4.0 t ha−1. Yield difference between attainable and average yield tended to be higher in irrigated and rainfed lowland systems. In those two systems, yields were highest in the semi-arid zone, while no difference in yields among climatic zones was apparent for upland rice. High rice yields were associated with high solar radiation, high maximum temperature, intermediate air humidity, multiple split nitrogen (N) fertilizer applications, high frequency of weeding operations, the use of certified seeds, and well-leveled fields in the irrigated lowland system. Minimum temperature, solar radiation, rainfall, construction of field bunds, varietal choice, and the frequency of weeding operations were determinants of rice yield variation in the rainfed lowland system. Varietal choice, bird control, and frequency of weeding operations affected rice yields in the upland system. Improving access to inputs, improving input use efficiencies, and site-specific management strategies are recommended as priority interventions to boost rice yields at regional scale independent of production system and climatic zone.
A multi-location study was conducted to assess the nitrogen (N), phosphorous (P) and potassium (K... more A multi-location study was conducted to assess the nitrogen (N), phosphorous (P) and potassium (K) requirements of lowland rice (Oryza sativa L.) for a local variety Digang cultivated in the northern Savannahs of Ghana and offer site specific nutrient recommendations. Ten on-farm nutrient omission trials involving five rates of N, P and K combinations were conducted during 2010 cropping season in Sudan and Guinea Savannah agro-ecological zones. The treatments (kg/ha as N, P2O5 and K2O) comprised 0-0-0 (control), 0-90-90 (zero N), 90-0-90 (zero P), 90-90-0 (zero K), 90-90-90 (NPK). Grain yields were increased by applying fertilizer N, P and K in sufficient amounts (90 N, 90 P2O5 and 90 K2O kg/ha) to overcome deficiencies and maintain soil fertility. Nitrogen was a major limiting nutrient in the irrigated and rain fed lowlands in the northern Savannahs of Ghana. The N-limited yields varied between 832 and 1875 kg/ha, suggesting variability of N supplying capacity of the experimental p...
Lack of a suitable sowing date has often been identified as the main constraint to sorghum (Sorgh... more Lack of a suitable sowing date has often been identified as the main constraint to sorghum (Sorghum bicolor Moench) cv. ICSV111 (Kapaala) production in Ghana. Field experiments were, therefore, used on-station at the Manga Agricultural Research Station to evaluate the effects of five sowing dates on yield and yield components of ‘Kapaala\' in northern Ghana. Sowing dates significantly (P Le manque de date de semialles appropriee a ete souvent indique comme la principale entrave a la production de sorgho (Sorghum bicolor Moench) var. ICSV111 (Kapaala) au Ghana. Des experiences sur le terrain etaient donc entreprises sur place au Centre de Recherche Agricole de Manga pour evaluer les effets de cinq dates de semailles sur le rendement et les elements de rendement de ‘Kapaala\' dans le nord du Ghana. Les dates de semailles influencaient considerablement (P Ghana Journal of Agricultural Science Vol. 40 (1) 2007: pp. 11-20
Abstract Although increase in rice (Oryza spp.) production is a common objective for rice-produci... more Abstract Although increase in rice (Oryza spp.) production is a common objective for rice-producing countries in sub-Saharan Africa (SSA), basic information on yield and its variation at farm level is lacking. Field surveys were conducted in irrigated lowland (IL), rainfed lowland (RL), and rainfed upland (RU) rice production systems in 19 SSA countries in the 2012–2014 wet seasons. Mean yield varied widely across sites: 2.2–5.8 t/ha, 1.1–5.2 t/ha, and 1.0–2.5 t/ha in IL, RL, and RU, respectively. Rice yield levels differed between the agro-ecological zones (AEZs) with the highest yield in the semi-arid zone in IL, and in the highlands zone for RL and RU. Cluster analysis identified four groups using mean yields, coefficient of variation, and skewness of yield distribution of 42 site–production system combinations. Grouping was related to production system, AEZ, and field water condition. A high-yielding group with 5.3 t/ha mean yield and negative skewness had only four site–production system combinations. Other groups had mean yields from 1.6 to 3.5 t/ha with positive skewness. In these groups, research and development priority for lifting rice yield could be given to low-yielding IL and RL sites with large yield gaps. Raising rice yield in the humid zone irrespective of the production systems and RU across AEZs remain major challenges. Further assessment of the impact of farmers’ agricultural practices on yield variation is warranted to identify potential interventions to realize further yield enhancement.
The yield of lowland paddy rice (Oryza sativa L.) is sensitive to water application regimes, whic... more The yield of lowland paddy rice (Oryza sativa L.) is sensitive to water application regimes, which can be affected by irrigation management. This study assessed the impacts of different irrigation applications on rice yield using the AquaCrop model. Experiments were conducted at two sites (On-station and On-farm) during the 2012/2013 and 2013/2014 dry seasons using five different irrigation treatments: field capacity (FC) moisture content (W 1 ), saturated soil moisture content (SC; W 2 ), continuous flooding (CF; W 3 ), 10ETc (crop water requirement) (W 4 ), and 15ETc (W 5 ). A 115-day rice variety, Gbewaa (Jasmine 85), was transplanted with a spacing of 20 cm × 20 cm for the experiments. The AquaCrop model was calibrated in terms of green canopy cover (CC), aboveground dry biomass, harvest index (HI), and paddy rice yield. The model was validated using various efficiency criteria (coefficient of determination, root mean square error (RMSE), RMSE–observations, standard deviation ra...
International Journal of Plant and Soil Science, 2021
The influence of zinc and sulfur on growth and yield of rice was studied for two soils; fallowed ... more The influence of zinc and sulfur on growth and yield of rice was studied for two soils; fallowed and continuously cropped. It was a 2 x 4 x 4 factorial experiment laid out in a randomized complete block design with three replicates, using lixisols of northern Ghana. Sulfur was applied as Sodium Sulfate (Na2SO4) at 0, 10, 20, 30 kg S/ha, two days after transplanting. Whilst zinc was applied as Zinc oxide (ZnO) at 0, 4, 8, 12 kg Zn/ha before transplanting. All soils received same rates of NPK (90-60-30 Kg/ha). An initial physico-chemical analysis conducted on the soils revealed that, both were sandy loam in texture and low in zinc but moderately high in sulfur. The fallowed soil was high in all other measured soil nutrients except nitrogen when compared to the cropped soil. The experimental results showed that, rice growth (tiller number, plant height), grain yield parameters (panicle count, percentage filled grains, grain yield) and straw yields are maximized by at least inclusion of...
International Journal of Agriculture Innovations and Research, 2015
An article published by International Journal of Agriculture Innovations and Research Volume 3, I... more An article published by International Journal of Agriculture Innovations and Research Volume 3, Issue 4, 2015
International Journal of Sciences: Basic and Applied Research, 2016
The upland field study was conducted during the 2014 major crop growing season under rainfed cond... more The upland field study was conducted during the 2014 major crop growing season under rainfed condition on a sandy loam soil (Ferric Acrisol) to compare the effect of different tillage practices and weeding frequency on yield parameters and yield of NERICA 4 rice variety at the Savannah Agricultural Research Institute of the Council for Scientific and Industrial Research, Nyankpala, Northern Region of Ghana. The experiment was arranged in a split plot design with three replications. The tillage treatments consisted of disc ploughing only, disc ploughing followed by disc harrowing, and no tillage as main plots and four weeding frequencies (weeding thrice, twice, once and no weeding) as sub-plots. The results indicated significant effects of tillage practices on the yield components and yield of NERICA 4. Disc ploughing followed by disc harrowing produced the highest number of panicles, panicle weight, number of spikelet's per panicle, dry matter yield, number of grains per panicle...
This paper underscores the influence of different fertilizers application on the growth, yield an... more This paper underscores the influence of different fertilizers application on the growth, yield and some trace elements uptake of two released local rice varieties widely cultivated and consumed in northern Ghana. Field experiments were conducted at the Council for Scientific and Industrial Research – Savanna Agricultural Research Institute at Nyankpala in the Northern Region of Ghana, to compare the performance of the rice varieties, viz . Digan and Nabogu. They were treated with three different inorganic fertilizers – NPK 15-15-15 (NPK), Sulphate of Ammonia (SA) and Triple Super Phosphate (TSP) and a control plot with no fertilizer treatment. The variety, Digan, showed shorter number of days (95) to 50% flowering than the Nabogu variety (107 days). The Digan variety yielded more under NPK and SA treatments than the Nabogu variety. The trace elements, Cd and Pb uptake by the two rice varieties were also assessed and found to be below detection limits. Fe and Mn were detected at an ...
Farmers’ participation in agricultural projects has a direct bearing on technology awareness, ado... more Farmers’ participation in agricultural projects has a direct bearing on technology awareness, adoption, livelihoods, environment, nutrition, poverty, performance of the agricultural sector and the macro economy. This study therefore sought to identify factors, which delimitate farmer’s participation in agricultural projects using the case of the Agricultural Value Chain Mentorship Project. A multi-stage sampling technique was employed to collect cross sectional data from 180 farmers in the Saboba and Chereponi districts of the Northern Region of Ghana. The study adopts the binary probit model and results of the analysis indicate that number of years in school, access to production credit and agricultural extension service are factors that significantly determine farmer’s participation in agricultural projects. It appears that farmer’s interest in agricultural projects can be permanently sustained by providing them with tangible benefits such as production credit and agricultural ext...
The major limiting factor for irrigated rice cultivation is water. As the demand for effective ma... more The major limiting factor for irrigated rice cultivation is water. As the demand for effective management of water increase due to climate change, future rice production will depend heavily on developing and adopting strategies and practices that use efficient water application. The objectives were to evaluate effects of different irrigation regimes on crop and economic water productivities as well as water balance for dry season irrigated rice production. This was to enable rice farmers and irrigation management to make an informed decision on the most economic and efficient water use regime for rice production. Two experiments were conducted using a randomized complete block design with 4 replications at On-Station (SARI) and On-Farm (Bontanga Irrigation Scheme) in 2012/2013 and 2013/2014 dry seasons. The treatments were, surface irrigation with applied water equal to: the Field Capacity (FC) moisture content ( W 1 ); Saturated soil moisture content (SC) ( W 2 ); Continuous floodi...
Abstract Increasing temperatures and water scarcity are concomitant threats to sustainable rice p... more Abstract Increasing temperatures and water scarcity are concomitant threats to sustainable rice production in future climates. Although both aspects have been widely studied, little is understood about how water-saving management might affect heat-induced stress and grain yield of rice under open-field conditions. The objective was to clarify how water management practices affect daily inner-canopy temperature (Tc) dynamics, flowering time, heat-induced spikelet sterility, and rice grain yield. Field experiments were conducted in four consecutive wet and dry seasons in northern Ghana. Two rice varieties, IR64 and Jasmine85, were grown under two water regimes: 1) continuous flooding (FL), and 2) continuous flooding except for an approximately 20-day drainage treatment at the flowering period (DF). Although the DF treatment was non-flooded, a high moisture content was maintained (>60 % of saturated volumetric water) to avoid any significant drought stress. The effect of water regimes on grain yield and Tc differed significantly between the dry season (DS) and wet season (WS). DF significantly reduced yields by 13–26 % in the DS but not in the WS. However, the effect of DF on Tc at flowering time (0.2–0.3 °C increase) and spikelet sterility (3–5% increase) was relatively small even in the DS. In contrast, DF greatly increased Tc from solar noon to midnight, in particular during the period of ±3 h from sunset in the DS. At this time of the day, DF had a higher Tc than FL by 0.7–0.9 °C on average. The Tc did not differ between DF and FL either at flowering time or nighttime in the WS. The Tc changes over the course of the day imply that water-saving management may have a higher risk of yield reduction in the DS of the sub-humid tropics not only by increasing heat-induced sterility but also by increasing late-afternoon-to-nighttime temperatures, which can cause physiological stress and respiration loss. These results can help improve water-saving management practices under contrasting climatic conditions in the sub-humid tropics and predict the combined effect of increasing temperatures and water scarcity on rice production.
If future rice production is to contribute to food security for the increasing population of sub-... more If future rice production is to contribute to food security for the increasing population of sub-Saharan Africa (SSA), effective strategies are needed to control weeds, the crop’s fiercest competitors for resources. To gain better insights into farmers’ access to, and use of, herbicides as part of weed control strategies, surveys were conducted in key rice production locations across SSA. Farm surveys were held among 1965 farmers across 20 countries to collect data on rice yields, farmer’s weed management practices, herbicide use, frequencies of interventions and information sources regarding herbicides. Markets were surveyed across 17 countries to collect data on herbicide availability, brand names and local prices (converted to US$ ha−1). Herbicides are used by 34% of the rice farmers in SSA, but adoption ranges from 0 to 72% across countries. Herbicides are more often used by men (40%) than by women (27%) and more often in irrigated (44% of farmers) than in rainfed lowland (36%) ...
Abstract Nutrient deficiencies are considered major constraints to rice production in sub-Saharan... more Abstract Nutrient deficiencies are considered major constraints to rice production in sub-Saharan Africa (SSA), but a systematic, continent-wide analysis of these constraints is lacking. The objective of this study was to assess responses of rice yields to macronutrients (N, P, and K) across major rice production systems [irrigated lowland rice (IL), rainfed lowland rice (RL), and rainfed upland rice (RU)] and diverse agro-ecological zones (semi-arid, sub-humid, humid, and highlands) in SSA. Diagnostic trials were conducted in 17 countries in 18–60 farmers' fields in each of 30 sites (totaling 1037 farmers' fields), of which 12 sites were in IL, 15 in RL and 3 in RU. All trials had an NPK treatment, and three treatments in which either nitrogen (N), phosphorus (P), or potassium (K) was omitted from the NPK treatment (minus N, P, and K plots). The trials were conducted during one or two seasons. Regression between yields in the NPK and minus N plots was used for calculating N fertilizer requirement, following the approach used for the development of a nutrient management decision support tool for rice (RiceAdvice) in SSA. Site mean yields in the NPK treatment ranged from 1.4 to 7.3 t ha−1. On average, these yields were 1.1 t ha−1 higher than farmers' yields previously observed in the same sites. N was generally the most limiting nutrient, followed by P. Rice yields without N, P, and K were 68, 84, and 89% of yields in the NPK treatment, and were positively correlated with those in the NPK treatment irrespective of production systems and agro-ecological zone (AEZ). Results from a regression model across sites indicated that achieving 3, 5, and 7 t ha−1 requires N fertilizer application at an average rate of 56, 91, and 122 kg N ha−1, respectively. However, there was significant treatment by site interaction on rice yield. Site mean yields were significantly lower without N, P, and K in 93, 60, and 50% of sites as compared to the NPK treatment. Yield response to macronutrients varied across sites and was not related to production system, nor AEZ. Results from this study will help further improvement of RiceAdvice for providing decision support tailored to the particular site, zone, or production system, thereby closing yield gaps, improving fertilizer nutrient efficiency and preventing negative environmental consequences of fertilizer use.
Rice (Oryza spp.) is the major staple food for most countries in West Africa, but local productio... more Rice (Oryza spp.) is the major staple food for most countries in West Africa, but local production does not meet demand. Rice is grown mainly by smallholder farmers, and yields are generally low with high temporal and spatial variability. Low yields have been attributed to unfavorable climate conditions, poor soil quality, and sub-optimum agricultural practices. The objectives of this study were to assess variation in yields of three major rice production systems (irrigated lowland, rainfed lowland, and upland) across three climatic zones (semi-arid, sub-humid, and humid), and identify factors affecting that variation. We analyzed data on yield, climate, soil, and agricultural practices for 1305 farmers’ fields at 22 sites in 11 West African countries between 2012 and 2014. A boundary function approach was used to determine attainable yields. Random forest algorithm was used to identify factors responsible for yield variation. Average rice yield was 4.1, 2.0, and 1.5 t ha−1 in irrigated lowland, rainfed lowland, and rainfed upland systems, respectively, with maximum attainable yields of 8.3, 6.5, and 4.0 t ha−1. Yield difference between attainable and average yield tended to be higher in irrigated and rainfed lowland systems. In those two systems, yields were highest in the semi-arid zone, while no difference in yields among climatic zones was apparent for upland rice. High rice yields were associated with high solar radiation, high maximum temperature, intermediate air humidity, multiple split nitrogen (N) fertilizer applications, high frequency of weeding operations, the use of certified seeds, and well-leveled fields in the irrigated lowland system. Minimum temperature, solar radiation, rainfall, construction of field bunds, varietal choice, and the frequency of weeding operations were determinants of rice yield variation in the rainfed lowland system. Varietal choice, bird control, and frequency of weeding operations affected rice yields in the upland system. Improving access to inputs, improving input use efficiencies, and site-specific management strategies are recommended as priority interventions to boost rice yields at regional scale independent of production system and climatic zone.
A multi-location study was conducted to assess the nitrogen (N), phosphorous (P) and potassium (K... more A multi-location study was conducted to assess the nitrogen (N), phosphorous (P) and potassium (K) requirements of lowland rice (Oryza sativa L.) for a local variety Digang cultivated in the northern Savannahs of Ghana and offer site specific nutrient recommendations. Ten on-farm nutrient omission trials involving five rates of N, P and K combinations were conducted during 2010 cropping season in Sudan and Guinea Savannah agro-ecological zones. The treatments (kg/ha as N, P2O5 and K2O) comprised 0-0-0 (control), 0-90-90 (zero N), 90-0-90 (zero P), 90-90-0 (zero K), 90-90-90 (NPK). Grain yields were increased by applying fertilizer N, P and K in sufficient amounts (90 N, 90 P2O5 and 90 K2O kg/ha) to overcome deficiencies and maintain soil fertility. Nitrogen was a major limiting nutrient in the irrigated and rain fed lowlands in the northern Savannahs of Ghana. The N-limited yields varied between 832 and 1875 kg/ha, suggesting variability of N supplying capacity of the experimental p...
Lack of a suitable sowing date has often been identified as the main constraint to sorghum (Sorgh... more Lack of a suitable sowing date has often been identified as the main constraint to sorghum (Sorghum bicolor Moench) cv. ICSV111 (Kapaala) production in Ghana. Field experiments were, therefore, used on-station at the Manga Agricultural Research Station to evaluate the effects of five sowing dates on yield and yield components of ‘Kapaala\' in northern Ghana. Sowing dates significantly (P Le manque de date de semialles appropriee a ete souvent indique comme la principale entrave a la production de sorgho (Sorghum bicolor Moench) var. ICSV111 (Kapaala) au Ghana. Des experiences sur le terrain etaient donc entreprises sur place au Centre de Recherche Agricole de Manga pour evaluer les effets de cinq dates de semailles sur le rendement et les elements de rendement de ‘Kapaala\' dans le nord du Ghana. Les dates de semailles influencaient considerablement (P Ghana Journal of Agricultural Science Vol. 40 (1) 2007: pp. 11-20
Abstract Although increase in rice (Oryza spp.) production is a common objective for rice-produci... more Abstract Although increase in rice (Oryza spp.) production is a common objective for rice-producing countries in sub-Saharan Africa (SSA), basic information on yield and its variation at farm level is lacking. Field surveys were conducted in irrigated lowland (IL), rainfed lowland (RL), and rainfed upland (RU) rice production systems in 19 SSA countries in the 2012–2014 wet seasons. Mean yield varied widely across sites: 2.2–5.8 t/ha, 1.1–5.2 t/ha, and 1.0–2.5 t/ha in IL, RL, and RU, respectively. Rice yield levels differed between the agro-ecological zones (AEZs) with the highest yield in the semi-arid zone in IL, and in the highlands zone for RL and RU. Cluster analysis identified four groups using mean yields, coefficient of variation, and skewness of yield distribution of 42 site–production system combinations. Grouping was related to production system, AEZ, and field water condition. A high-yielding group with 5.3 t/ha mean yield and negative skewness had only four site–production system combinations. Other groups had mean yields from 1.6 to 3.5 t/ha with positive skewness. In these groups, research and development priority for lifting rice yield could be given to low-yielding IL and RL sites with large yield gaps. Raising rice yield in the humid zone irrespective of the production systems and RU across AEZs remain major challenges. Further assessment of the impact of farmers’ agricultural practices on yield variation is warranted to identify potential interventions to realize further yield enhancement.
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