On-farm rice yield and its association with biophysical factors in sub-Saharan Africa

SUMMARYIn sub-Saharan Africa, the bollworm complex, including Helicoverpa armigera, Diparopsis watersi and Earias spp., threatens the continued success of cotton production. Pyrethroid resistance in H. armigera led to serious crop losses while endosulfan, a suitable alternative to pyrethroids, was banned for cotton pest management. Five candidates with no cross-resistance to pyrethroids were evaluated in both on-station and on-farm trials from 2002 to 2006. Two applications were made at the early peak of H. armigera infestation in September, the period when pyrethroid use should be restricted for resistance management purposes. Results showed that, as expected, bollworm infestation consistently peaked from mid-September to mid-October. Spinosad, thiodicarb and emamectin-benzoate were the most suitable alternatives to reduce damage, regardless of the cotton bollworm species. Indoxacarb and lufenuron were less effective in controlling D. watersi. On-farm experiments confirmed the suitability of spinosad for control of pyrethroid-resistant H. armigera, particularly on late sown fields. These new chemistries offer control of bollworms which justify their relevance for pyrethroid resistance management in Cameroon and sub-Saharan Africa.

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Application of a Bayesian approach to quantify the impact of nitrogen fertilizer on upland rice yield in sub-Saharan Africa

Field Crops Research ◽

10.1016/j.fcr.2021.108284 ◽

2021 ◽

Vol 272 ◽

pp. 108284

Author(s):

Hidetoshi Asai ◽

Kazuki Saito ◽

Kensuke Kawamura

Keyword(s):

Bayesian Approach ◽

Nitrogen Fertilizer ◽

Rice Yield ◽

Upland Rice ◽

Sub Saharan Africa ◽

Sub Saharan ◽

The Impact

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WHICH OPTIONS FIT BEST? OPERATIONALIZING THE SOCIO-ECOLOGICAL NICHE CONCEPT

Experimental Agriculture ◽

10.1017/s001447971600048x ◽

2016 ◽

Vol 55 (S1) ◽

pp. 169-190 ◽

Cited By ~ 15

Author(s):

KATRIEN DESCHEEMAEKER ◽

ESTHER RONNER ◽

MARY OLLENBURGER ◽

ANGELINUS C. FRANKE ◽

CHARLOTTE J. KLAPWIJK ◽

...

Keyword(s):

Systems Analysis ◽

Ecological Niche ◽

Smallholder Farmers ◽

Farming Systems ◽

Sub Saharan Africa ◽

Cultural Economic ◽

Niche Concept ◽

Sub Saharan ◽

Farming Systems Analysis ◽

On Farm

SUMMARYThe large diversity of farms and farming systems in sub-Saharan Africa calls for agricultural improvement options that are adapted to the context in which smallholder farmers operate. The socio-ecological niche concept incorporates the agro-ecological, socio-cultural, economic and institutional dimensions and the multiple levels of this context in order to identify which options fit best. In this paper, we illustrate how farming systems analysis, following the DEED cycle of Describe, Explain, Explore and Design, and embedding co-learning amongst researchers, farmers and other stakeholders, helps to operationalize the socio-ecological niche concept. Examples illustrate how farm typologies, detailed farm characterization and on-farm experimental work, in combination with modelling and participatory approaches inform the matching of options to the context at regional, village, farm and field level. Recommendation domains at these gradually finer levels form the basis for gradually more detailed baskets of options from which farmers and other stakeholders may choose, test and adjust to their specific needs. Tailored options identified through the DEED cycle proof to be more relevant, feasible and performant as compared to blanket recommendations in terms of both researcher and farmer-identified criteria. As part of DEED, on-farm experiments are particularly useful in revealing constraints and risks faced by farmers. We show that targeting options to the niches in which they perform best, helps to reduce this risk. Whereas the conclusions of our work about the potential for improving smallholders’ livelihoods are often sobering, farming systems analysis allows substantiating the limitations of technological options, thus highlighting the need for enabling policies and institutions that may improve the larger-scale context and increase the uptake potential of options.

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Making the best of climatic variability: options for upgrading rainfed farming in water scarce regions

Water Science & Technology ◽

10.2166/wst.2004.0442 ◽

2004 ◽

Vol 49 (7) ◽

pp. 151-156 ◽

Cited By ~ 11

Author(s):

J. Rockström

Keyword(s):

Soil Fertility ◽

Water Scarcity ◽

Social Impact ◽

Climatic Variability ◽

Sub Saharan Africa ◽

Dry Spells ◽

Rainfed Farming ◽

Dry Spell ◽

Sub Saharan ◽

On Farm

Coping with climatic variability for livelihood security is part of everyday life for rural communities in semi-arid and dry sub-humid savannas. Water scarcity caused by rainfall fluctuations is common, causing meteorological droughts and dry spells. However, this paper indicates, based on experiences in sub-Saharan Africa and India, that the social impact on rural societies of climatically induced droughts is exaggerated. Instead, water scarcity causing food deficits is more often caused by management induced droughts and dry spells. A conceptual framework to distinguish between manageable and unmanageable droughts is presented. It is suggested that climatic droughts require focus on social resilience building instead of land and water resource management. Focus is then set on the manageable part of climatic variability, namely the almost annual occurrence of dry spells, short 2–4 week periods of no rainfall, affecting farmer yields. On-farm experiences in savannas of sub-Saharan Africa of water harvesting systems for dry spell mitigation are presented. It is shown that bridging dry spells combined with soil fertility management can double and even triple on-farm yield levels. Combined with innovative systems to ensure maximum plant water availability and water uptake capacity, through adoption of soil fertility improvement and conservation tillage systems, there is a clear opportunity to upgrade rainfed farming systems in vulnerable savanna environments, through appropriate local management of climatic variability.

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Efficacy and Costs of Handheld Sprayers in the Subhumid Savanna for Cogongrass Control

Weed Technology ◽

10.1614/wt-03-267r2.1 ◽

2005 ◽

Vol 19 (3) ◽

pp. 568-574 ◽

Cited By ~ 3

Author(s):

Ole K. Nielsen ◽

David Chikoye ◽

Jens C. Streibig

Keyword(s):

Sub Saharan Africa ◽

Response Curves ◽

Knapsack Sprayer ◽

Sub Saharan ◽

High Doses ◽

Hand Weeding ◽

Carrier Volume ◽

User Friendly ◽

On Farm ◽

Very High

Cogongrass continues to be one of the most invasive weeds in the subhumid savanna. Herbicide application expenses depend on equipment costs, costs of water transport for spraying, and chemical costs. In three on-farm experiments on land heavily infested with cogongrass, the effectiveness of a knapsack sprayer (KS), a very low volume sprayer (VLV), and a rope wick (RW) applicator was tested at Ijaye, Nigeria, from 2000 to 2001. The sprayers differed in application method, price, and carrier volume required. The dose–response curves for the three applicators were identical in all parameters except at very high doses for the RW. Consequently, there were no apparent differences in glyphosate effectiveness, even when it was applied with different equipment and different carrier volumes. However, even at very high doses, the RW was not as efficient as was the KS and VLV. Actual biomass reduction of cogongrass was greater with the KS and VLV. Even though the KS and VLV generally gave better control levels than the RW, the latter is more user-friendly because it does not require protective masks, which are often unavailable in sub-Saharan Africa. In a situation with labor scarcity, weeding with the RW was cheaper than hand weeding with hoes. The VLV was more economical when used on areas larger than 10 ha than was the RW. The KS was more economical than all other methods when used on areas larger than 2 ha.

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History and progress in genetic improvement for enhancing rice yield in sub-Saharan Africa

Field Crops Research ◽

10.1016/j.fcr.2021.108159 ◽

2021 ◽

Vol 267 ◽

pp. 108159

Author(s):

Koichi Futakuchi ◽

Kalimuthu Senthilkumar ◽

Aminou Arouna ◽

Elke Vandamme ◽

Mandiaye Diagne ◽

...

Keyword(s):

Genetic Improvement ◽

Rice Yield ◽

Sub Saharan Africa ◽

Sub Saharan

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Quantifying the prevalence of (non)-response to fertilizers in sub-Saharan Africa using on-farm trial data

Nutrient Cycling in Agroecosystems ◽

10.1007/s10705-021-10174-1 ◽

2021 ◽

Author(s):

Generose Nziguheba ◽

Joost van Heerwaarden ◽

Bernard Vanlauwe

Keyword(s):

Response Variability ◽

Sub Saharan Africa ◽

Fertilizer Response ◽

Local Conditions ◽

Production Risk ◽

Residual Variation ◽

Actual Field ◽

Sub Saharan ◽

Fertilizer Adoption ◽

On Farm

AbstractPoor and variable crop responses to fertilizer applications constitute a production risk and may pose a barrier to fertilizer adoption in sub-Saharan Africa (SSA). Attempts to measure response variability and quantify the prevalence of non-response empirically are complicated by the fact that data from on-farm fertilizer trials generally include diverse nutrients and do not include on-site replications. The first aspect limits the extent to which different studies can be combined and compared, while the second does not allow to distinguish actual field-level response variability from experimental error and other residual variations. In this study, we assembled datasets from 41 on-farm fertilizer response trials on cereals and legumes across 11 countries, representing different nutrient applications, to assess response variability and quantify the frequency of occurrence of non-response to fertilizers. Using two approaches to account for residual variation, we estimated non-response, defined here as a zero agronomic response to fertilizer in a given year, to be relatively rare, affecting 0–1 and 7–16% of fields on average for cereals and legumes respectively. The magnitude of response could not be explained by climatic and selected topsoil variables, suggesting that much of the observed variation may relate to unpredictable seasonal and/or local conditions. This implies that, despite demonstrable spatial bias in our sample of trials, the estimated proportion of non-response may be representative for other agro-ecologies across SSA. Under the latter assumption, we estimated that roughly 260,000 ha of cereals and 3,240,000 ha of legumes could be expected to be non-responsive in any particular year.

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Delivering sustainable crop protection systems via the seed: exploiting natural constitutive and inducible defence pathways

Philosophical Transactions of the Royal Society B Biological Sciences ◽

10.1098/rstb.2012.0281 ◽

2014 ◽

Vol 369 (1639) ◽

pp. 20120281 ◽

Cited By ~ 12

Author(s):

John A. Pickett ◽

Gudbjorg I. Aradottír ◽

Michael A. Birkett ◽

Toby J. A. Bruce ◽

Antony M. Hooper ◽

...

Keyword(s):

Pest Management ◽

Crop Protection ◽

Sub Saharan Africa ◽

Lead Compounds ◽

Planting Material ◽

Protection Systems ◽

Sustainable Crop Protection ◽

Sub Saharan ◽

On Farm ◽

New Breeding Technologies

To reduce the need for seasonal inputs, crop protection will have to be delivered via the seed and other planting material. Plant secondary metabolism can be harnessed for this purpose by new breeding technologies, genetic modification and companion cropping, the latter already on-farm in sub-Saharan Africa. Secondary metabolites offer the prospect of pest management as robust as that provided by current pesticides, for which many lead compounds were, or are currently deployed as, natural products. Evidence of success and promise is given for pest management in industrial and developing agriculture. Additionally, opportunities for solving wider problems of sustainable crop protection, and also production, are discussed.

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Estimating the causal effect of improved fallows on environmental services provision under farmers' field conditions in Chongwe, Zambia

Environment and Development Economics ◽

10.1017/s1355770x14000011 ◽

2014 ◽

Vol 20 (1) ◽

pp. 80-100 ◽

Cited By ~ 2

Author(s):

Elias Kuntashula ◽

Eric Mungatana

Keyword(s):

Causal Effect ◽

Sub Saharan Africa ◽

Public Land ◽

Environmental Services ◽

Improved Fallows ◽

Fuel Wood ◽

Sub Saharan ◽

Using Data ◽

Wood Consumption ◽

On Farm

AbstractThe provision of environmental services on-farm by the improved fallow (an agroforestry technology) has largely remained empirically untested in sub-Saharan Africa. Where effects of planting trees have been used to estimate the impacts on consumption of fuel wood from public land, actual estimates of the size of fuel wood consumption changes have been lacking. Using data from a survey of 324 households in the Chongwe district of Zambia, we tested the hypothesis that households embracing improved fallows use less fuel wood from public land since the technology provides wood as a by-product. Estimates from ordered probit and matching strategies showed that the technology had a significant causal effect of reducing the consumption of fuel wood from public land. Therefore, in addition to promoting it for soil fertility improvement, the extension messages should explicitly reflect the technology's potential to provide on-farm environmental quality.

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