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Rodenburg J.,Africa Rice Center | Zwart S.J.,Africa Rice Center | Kiepe P.,Africa Rice Center | Narteh L.T.,Food and Agriculture Organization of the United Nations FAO | And 2 more authors.
Agricultural Systems | Year: 2014

With an estimated surface area of 190. M. ha, inland valleys are common landscapes in Africa. Due to their general high agricultural production potential, based on relatively high and secure water availability and high soil fertility levels compared to the surrounding uplands, these landscapes could play a pivotal role in attaining the regional objectives of food security and poverty alleviation. Besides agricultural production, i.e. mainly rice-based systems including fish-, vegetable- fruit- and livestock production, inland valleys provide local communities with forest, forage, hunting and fishing resources and they are important as water buffer and biodiversity hot spots. Degradation of natural resources in these vulnerable ecosystems, caused by indiscriminate development for the sole purpose of agricultural production, should be avoided. We estimate that, following improved water and weed management, production derived from less than 10% of the total inland valley area could equal the total current demand for rice in Africa. A significant part of the inland valley area in Africa could hence be safeguarded for other purposes.The objective of this paper is to provide a methodology to facilitate fulfilment of the regional agricultural potential of inland valleys in sub-Saharan Africa (SSA) such that local rural livelihoods are benefited and regional objectives of reducing poverty and increasing food safety are met, while safeguarding other inland-valley ecosystem services of local and regional importance. High-potential inland valleys should be carefully selected and developed and highly productive and resource-efficient crop production methods should be applied. This paper describes a participatory, holistic and localized approach to seize the regional potential of inland valleys to contribute to food security and poverty alleviation in sub-Saharan Africa. We analyzed over a 100 papers, reference works and databases and synthesized this with insights obtained from nearly two decades of research carried out by the Africa Rice Center and partners. We conclude that sustainable rice production in inland valleys requires a step-wise approach including: (1) the selection of '. best-bet' inland valleys, either new or already used ones, based on spatial modelling and a detailed feasibility study, (2) a stakeholder-participatory land use planning within the inland valley based on multi-criteria decision making (MCDM) methods and using multi-stakeholder platforms (MSP), (3) participatory inland-valley development, and (4) identification of local production constraints combining model simulations and farmer participatory priority exercises to select and adapt appropriate practices and technologies following integrated management principles. © 2013 Elsevier Ltd.

Naab J.B.,Savanna Agricultural Research Institute | Boote K.J.,University of Florida | Jones J.W.,University of Florida | Porter C.H.,University of Florida
Field Crops Research | Year: 2015

Phosphorus (P) deficiency is a major constraint to crop production in many agricultural systems globally. Application of phosphorus fertilizer is essential for optimal crop yields when soils are P limiting. Crop simulation models can provide an alternative, less time consuming and inexpensive means of determining the optimum crop P requirements under varied soil and climatic conditions. The CROPGRO-peanut model is capable of simulating the growth and yield of peanut in response to weather, soil, water, nitrogen and management practices but its capability in predicting crop responses to soil and fertilizer P needs to be established. Our objective was to adapt and evaluate the CROPGRO-peanut model within the DSSAT system to simulate the growth and yield of peanut (Arachis hypogaea) in response to soil and fertilizer P. Data from four P fertilizer treatments (0, 13, 26 and 39kgPha-1) and two cropping seasons (2002 and 2003) experiments on an Alfisol were used to calibrate the model. The model was tested using two data sets from a P fertilizer×cultivar trial conducted on-station in 1997 and 1998 and P fertilizer×fungicide trials on-farm in 2002. The limited testing showed that the P module accurately simulated the seasonal patterns of aboveground biomass and pod yield in the on-farm trials. Averaged across sampling dates RMSEs in the on-farm trials ranged from 100 to 398kgha-1 (d≥0.99) for total biomass and from 97 to 263kgha-1 (d values≥0.98) for pod yield. At final harvest, the variability of simulated biomass and pod yield was about 5.4 and 10.0% of the observed biomass and pod yield respectively. In the P fertilizer×cultivar trial, the variability of simulated biomass and pod yield were 22 and 13% for cv. F-Mix and 19 and 5% for cv. Chinese respectively. The model simulated the seasonal patterns of vegetative P content in the four farmers' fields fairly well with RMSEs ranging from 0.28 to 1.29kgha-1 when averaged across measurements dates. The model outputs were sensitive to soil P test values, the method of P fertilizer application and to plant P uptake factors, such as root P extraction radius and root length density. There were differences in the sensitivity of the simulations to changes in target tissue P concentrations. Increasing or decreasing the optimum P concentration of seed and minimum P concentrations of leaf and stem had the greatest effects on pod yield compared to other plant parts. We conclude that the generic soil and plant P model in DSSAT 4.5 is capable of simulating peanut growth and yield in response to soil P levels or fertilizer application on an Alfisol. © 2015 Elsevier B.V.

Buah S.S.J.,Savanna Agricultural Research Institute | Kombiok J.M.,Savanna Agricultural Research Institute | Abatania L.N.,University of Ghana
Journal of Crop Improvement | Year: 2012

Sorghum [Sorghum bicolor (L.) Moench] is an important food crop grown by subsistence farmers in Africa with little or no fertilizer. Field experiments were conducted in 2002 and 2003 on sandy loam soil in Guinea savanna of Ghana to determine the agronomic and economic benefits of applying nitrogen (N), phosphorus (P), and potassium (K) fertilizers to sorghum. Four N levels (0, 40, 80, and 120 kg -1 as urea) were combined with two P levels (0 and 17.2 kg P ha -1 as triple superphosphate) and two K levels (0 and 33.3 kg K ha -1 as muriate of potash) to constitute 16 treatments that were tested in a randomized complete-block design with three replications. Fertilizer N, P, and K did not show significant interactions for any parameter. Across years, added K did not influence grain yield and yield components. However, P increased yield by 14%, and N affected yield in a quadratic manner. The application of 40, 80, and 120 kg N ha -1 resulted in yield increases of 47%, 60% and 69% over farmers' practice (0 kg N ha -1), respectively. Economic analysis revealed that two N and P combinations, i.e., 40:0 and 40:17.2 kg ha -1, were economically superior and stable within a price variability range of 20%. Thus, farmers in the Guinea savanna agro-ecology in Africa can get better returns on the money invested in fertilizer for producing improved sorghum than with their traditional practice of no fertilizer input. © 2012 Taylor and Francis Group, LLC.

Pule-Meulenberg F.,Tshwane University of Technology | Gyogluu C.,Tshwane University of Technology | Naab J.,Savanna Agricultural Research Institute | Dakora F.D.,Tshwane University of Technology
Journal of Plant Physiology | Year: 2011

Six promiscuous soybean genotypes were assessed for their ability to nodulate with indigenous root-nodule bacteria in Ghana, with Bradyrhizobium japonicum WB74 serving as positive control. Although the results revealed free nodulation of all six genotypes in both inoculated and uninoculated plots, there was a marked effect of inoculation on photosynthetic rates and whole-plant C. Inoculation also increased stomatal conductance in TGx1485-1D, TGx1448-2E, TGx1740-2F and TGx1445-3E, leading to significantly elevated transpiration rates in the last two genotypes, and a decrease in TGx1485-1D, TGx1440-1E and Salintuya-1, resulting in reduced leaf transpiration and decreased C accumulation. Nodulation, total plant biomass, plant N concentration and content also increased and ∂15N of the six genotypes, except for TGx1448-2E decreased. Significantly higher %Ndfa resulted in all the soybean genotypes tested (except for TGx1485-1D), and the symbiotic N yield in TGx1740-2F and TGx1448-2E doubled. PCR-RFLP revealed 18 distinct IGS types present in root nodules of the six promiscuous soybean genotypes, with IGS type II being isolated from all six genotypes, followed by IGS types X and XI from five out of the six genotypes. Marked differences in strain IGS type symbiotic efficiency were revealed. For example, as sole nodule occupant, IGS type XI produced high symbiotic N in TGx1445-3E, but low amounts in TGx1448-2E. Inoculated Salintuya-1, which trapped nine strain IGS types in its root nodules, was the most promiscuous genotype, but produced less symbiotic N compared to genotypes with fewer strains in their root nodules. © 2010 Elsevier GmbH.

Abukari I.A.,Savanna Agricultural Research Institute | Shankle M.W.,North Mississippi Research and Extension Center | Reddy K.R.,Mississippi State University
Scientia Horticulturae | Year: 2015

The herbicide S-metolachlor is used to control or suppress annual grasses, nutsedges and several broadleaf weeds in sweetpotato. However, a decline in storage root quality is suspected when an excessive rainfall occurs within 24h after application. A sunlit, controlled environment experiment was conducted to investigate sweetpotato response to five levels of S-metolachlor (0.00, 0.86, 1.72, 2.58 and 3.44kgha-1), and two levels of simulated rainfall (0 and 38mm at 51mmh-1) immediately after application. Sweetpotato slips were transplanted into white polyvinyl chloride pots filled with sandy loam soil. S-metolachlor treatments were applied to slips and a simulated rainfall treatment delivered immediately after transplanting and herbicide treatment. All pots were transferred to sunlit growth chambers that were maintained at 30/22°C, day/night temperatures and ambient carbon dioxide concentration (400μLL-1) for 60 days. An evapotranspiration-based irrigation system was used to supply water and nutrients. Plant biomass components and quality of storage roots were recorded 60 days after transplanting. There was no difference between rainfall treatments across S-metolachlor rates for vine lengths, leaf numbers and leaf area. These parameters, however, declined linearly and significantly with increase in S-metolachlor concentration. Total storage root weight declined linearly with increased S-metolachlor concentration; the decline was steeper with simulated rainfall. Yield of marketable storage roots declined by 18 and 31% in the absence of rainfall and 55 and 79% in the presence of rainfall with S-metolachlor at minimum (0.86kgha-1) and maximum (1.43kgha-1) recommended label rates, respectively, used to control weeds. Yield reduction was directly proportional to the rate of S-metolachlor applied in the absence or presence of rainfall; 77 and 123g fresh weight kg-1ha-1 S-metolachlor for no-rainfall and rainfall treatment, respectively. These results can be used to improve management decisions to optimize yield under field conditions as well as to mitigate risk of injury that could be associated with the use of S-metolachlor in sweetpotato production systems. © 2015 Elsevier B.V.

Amagloh F.K.,University for Development Studies | Amagloh F.C.,Savanna Agricultural Research Institute | Coad J.,Massey University
International Food Research Journal | Year: 2016

The in vitro starch digestibility (IVSD) method ("as-is" or modification) was used to assess the digestibility of two sweetpotato-based complementary food (CF), denoted orange-fleshed ComFa and cream-fleshed ComFa, and two cereal-based CF: Cerelac (wheat-based commercial infant cereal) and Weanimix (maize-soybean-groundnut blend). Using the IVSD method ("asis"), the sweetpotato formulations with high maltose (averaging 22.24 g/100 g) and low starch, about 15.15 g/100 g, had far lower digestibility values of 6.29 g/100 g, a quarter of that for Weanimix, which contained maltose and starch at levels of 2.72 g/100 g and 48.38 g/100 g, respectively. Further, the IVSD method employed "as-is" estimated the digestibility of Cerelac to be 11.53 g/100 g, about half the value for Weanimix. Conversely, for the modified method, the sweetpotato-based formulations had estimated digestibility value about 3 times higher than Weanimix (63.91 g/100 g), and 1.5 times higher than Cerelac (117.76 g/100 g). The IVSD method ("as-is") gives false negative results when used to estimate the digestibility of CF that contain significant amount of endogenous maltose. Therefore, its application to predict the suitability of CF warrants further validation. © 2008 IFRJ.

Kombiok J.M.,Savanna Agricultural Research Institute
Tropical Agriculture | Year: 2013

The mean seed yield of sesame (Sesamum orientale L.) grown in Ghana by broadcasting the seeds is low. A field experiment to determine the effect of different plant populations and planting distances on the seed yield of sesame was conducted at Nyankpala in the northern Savanna zone of Ghana in 2009 and 2010. The treatments including row planting populations of 333,000/ha, 332,000/ha, 222,000/ha, 166,000/ha and broadcasting at the rate of 300,000 seeds/ha were laid out in randomized complete block design (RCBD) and replicated four times with SJ2 as the test crop variety. The most appropriate plant populations and planting distances that significantly (p< 0.05) increased seed yield/ha were 60 x 5 cm (333,000 plants/ha) and 60 x 10 cm spacing (332,000 plants/ha). Although plant population by broadcasting method was similar to the above; the seed yield was significantly (p<0.05) lower because the method of planting resulted in over-crowding which might have enhanced interplant competition for resources such as nutrients. Plant spacing (60 x 15 and 60 x 20 cm) that gave lower plant densities produced significantly (p<0.05) higher branches and pod number/plant but these could not be translated into higher seed yields/unit area as these compensatory factors were not enough to raise yields/unit area. Pod length, seeds/pod and plant height at harvest were not affected by plant population in the study. Farmers in the northern savanna zone of Ghana should therefore be sensitized and encouraged to adopt the 60 x 5 cm spacing at 1 plant/stand (333,000 plants/ha) or 60 x 10 cm spacing at 2 plants/stand for high sesame yields. The broadcasting method should be discouraged since it results in low seed yields and makes weed control, fertilizer application and harvesting more difficult © 2013 Trop. Agric. (Trinidad).

Sugri I.,Savanna Agricultural Research Institute | Nutsugah S.K.,Savanna Agricultural Research Institute | Yirzagla J.,Savanna Agricultural Research Institute
Research Journal of Seed Science | Year: 2011

To address the poor seed viability problem of pearl millet in Ghana, the influences of time of harvesting, some seed physical characteristic and moisture content relations on viability were evaluated. Harvesting was done on day 1,3, 5, 7 and 14 from the physiological maturity or the hard-dough stage. The seeds were also fractionated into <2, >2 and 1-3 mm grades. Data on seed moisture content, bulk density and thousand seed weight were determined. Standard germination tests were carried out and counting was done from day 3 to 9. An analysis of the physical environment revealed that the extreme dry conditions (Temperature~18-42°C, RH%~20-54) which prevail during the period of seed storage may provide opportunity for seed drying. Gradual increases in seed weight, bulk density and thousand seed weight occurred from day 1 to 5 and peaked by 7 days after hard-dough stage. Consistently high germination rates were attained by harvesting at 7 days after hard-dough. The seeds harvested at day 1, 3 and sometimes 5 showed abysmal performances for most vigor traits evaluated. Within 9 months of storage, low germination rate of 53.3-65.8% was recorded. Four varieties, Arrow millet, Bongo short head, Bristle millet and Tongo yellow, which exhibited large seed characteristics consistently showed higher germination rates compared with their counterparts Salma-1, Salma-3, Indiana-05 and Bangbensi millet. Across varieties, large seeds recorded higher germination rates compared with other grades. Seed vigor traits such as incidence of seedling abnormalities and days 3 to 5 leaf stages were positively related to early harvesting and large seed size. © 2011 Academic Journal Inc.

Ayamdoo A.J.,University for Development Studies | Demuyakor B.,University for Development Studies | Dogbe W.,Savanna Agricultural Research Institute | Owusu R.,Savanna Agricultural Research Institute | Ofosu M.A.,University for Development Studies
American Journal of Food Technology | Year: 2013

As part of research towards enhancing the value chain of parboiled rice in Ghana, a study was conducted to ascertain the ideal parboiling conhtion that optimizes the physical qualities of rice. The study was carried out at the Spanish Laboratory of University for Development Studies, Tamale, Ghana. Two rice varieties (Nerica 14 and Jasmine 85) were parboiled in the Laboratory at four different conditions (soaking and steaming time combinations) to ascertain the effects of each parboiling condition on the physical qualities of the parboiled rice. A combination of four (4) soaking times (6, 20, 24, 36 h) and three (3) steaming levels (40, 60, 90 min) was used. Samples were also taken from conventional parboiling groups and used as check alongside the control samples. The parboiled rice were milled and physical properties such as milling yeld, Head Rice Yield (HRY), colour, hardness, broken percentage, translucency and gelatinization temperature were evaluated. The results showed that parboiling at 20 to 24 h soaking with 60 min of steaming produced rice with best physical qualities except for colour i.e Wlling yeld was 80%, HRY was 60% and whiteness was 49%. The commercial samples gave values that were close to mehum parboiling. Also ANOVA results showed that soahng and steaming time have direct impact on the final quality of parboiled rice. It was recommended for processors to soak paddy rice for 20 h in warm water between 30 to 40°C followed by steaming for 60 min at 80°C to maximize the physical qualities of parboiled Jasmine 85 and Nerica 14. © 2013 Academic Journals Inc.

Siise A.,Savanna Agricultural Research Institute | Massawe F.J.,University of Nottingham Malaysia Campus
Genetic Resources and Crop Evolution | Year: 2013

Bambara groundnut an indigenous crop of African origin is drought tolerant and the third most important leguminous crop in Ghana and Sub-Saharan Africa. In order to assess the level of genetic diversity within a small collection of Ghanaian landraces, molecular analysis was performed using microsatellite markers alongside characterization of morphological features. Genetic distance based on Jaccard's similarity coefficient from the SSR marker analysis ranged from 0.48 to 0.9 among the landraces. 80 individual genotypes were clustered into 17 units with substantial levels of inter- and intra-landrace polymorphism. The analyses of variance from the morphological characterization for all quantitative traits were statistically significant (p < 0.05) except for terminal leaflet width. The first 4 principal components accounted for 41.97, 20.15, 13.39 and 9.81 % respectively of the morphological variations among the landraces. Qualitative traits however accounted for less of these variations. The results of the present study support the availability of high level of polymorphism within the collection of bambara groundnut analysed. This report is useful to crop improvement and germplasm conservation of bambara groundnut in Ghana. © 2012 Springer Science+Business Media Dordrecht.

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