Abstract
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%) or upland rice growing environments (24%). Herbicides are always used supplementary to hand weeding. Following this combination, yield loss reductions in irrigated lowlands and rainfed uplands are estimated to be 0.4 t ha−1 higher than hand weeding alone. In rainfed lowlands no benefits were observed from herbicide use. Sixty-two percent of the herbicides sold at rural agro-chemical supply markets are unauthorized. These markets are dominated by glyphosate and 2,4-D, sold under 55 and 41 different brand names, respectively, and at relatively competitive prices (below average herbicide price of US $17 ha−1). They are also the most popular herbicides among farmers. For advice on herbicide application methods, farmers primarily rely on their peers, and only a few receive advice from extension services (<23%) or inform themselves by reading the product label (<16%). Herbicide application timings are therefore often (38%) sub-optimal. Herbicide technologies can contribute to reduced production losses in rice in SSA. However, through negative effects on crop, environment and human health, incorrect herbicide use may unintentionally counteract efforts to increase food security. Moving away from this status quo will require strict implementation and monitoring of national pesticide regulations and investment in research and development to innovate and diversify the currently followed weed management strategies, agricultural service provision and communications with farmers.
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Claims 16
Claim · model-written summary
Herbicides were used by 34% of rice farmers in SSA.
- Taxon
- rice
Oryza sativae0 - Outcome
- Herbicides are usede0
- Value
- 34%e0
- Setting
- SSAe0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Herbicides are used by 34% of the rice farmers in SSA”
Claim · model-written summary
Herbicide adoption ranged from 0 to 72% across countries.
- Taxon
- riceOryza sativat0
- Outcome
- adoptione0
- Value
- 0 to 72%e0
- Setting
- countriese0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“adoption ranges from 0 to 72% across countries”
t0“rice”
Claim · model-written summary
Herbicide use was more frequent among men than women.
- Taxon
- riceOryza sativat0
- Outcome
- Herbicides are more often usede0
- Value
- 40%e0
- Qualifier
- 27%e0
- Comparator
- womene0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Herbicides are more often used by men (40%) than by women (27%)”
t0“rice”
Claim · model-written summary
Herbicide use was more frequent in irrigated than rainfed lowland or upland rice systems.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“more often in irrigated (44% of farmers) than in rainfed lowland (36%) or upland rice growing environments (24%)”
Claim · model-written summary
Herbicides were always supplementary to hand weeding.
- Taxon
- riceOryza sativat0
- Outcome
- Herbicides are always used supplementary to hand weedinge0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Herbicides are always used supplementary to hand weeding”
t0“rice”
Claim · model-written summary
Herbicide use with hand weeding increased estimated yield loss reductions in irrigated lowlands and rainfed uplands by 0.4 t ha−1 relative to hand weeding alone.
- Taxon
- riceOryza sativat0
- Treatment
- herbicide usee1
- Outcome
- yield loss reductionse0
- Direction
- highere0
- Value
- 0.4 t ha−1e0
- Comparator
- hand weeding alonee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“yield loss reductions in irrigated lowlands and rainfed uplands are estimated to be 0.4 t ha−1 higher than hand weeding alone”
e1“In rainfed lowlands no benefits were observed from herbicide use”
t0“rice”
Claim · model-written summary
Herbicide use showed no benefit in rainfed lowlands.
- Taxon
- riceOryza sativat0
- Treatment
- herbicide usee0
- Outcome
- benefitse0
- Direction
- no benefitse0
- Setting
- rainfed lowlandse0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“In rainfed lowlands no benefits were observed from herbicide use”
t0“rice”
Claim · model-written summary
Sixty-two percent of herbicides sold at rural agrochemical markets were unauthorized.
- Taxon
- riceOryza sativat0
- Outcome
- herbicides sold at rural agro-chemical supply markets are unauthorizede0
- Value
- Sixty-two percente0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Sixty-two percent of the herbicides sold at rural agro-chemical supply markets are unauthorized”
t0“rice”
Claim · model-written summary
Glyphosate was sold under 55 brand names.
- Taxon
- riceOryza sativat0
- Outcome
- glyphosatee0
- Value
- 55e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“glyphosate and 2,4-D, sold under 55 and 41 different brand names, respectively”
t0“rice”
Claim · model-written summary
2,4-D was sold under 41 brand names.
- Taxon
- riceOryza sativat0
- Outcome
- 2,4-De0
- Value
- 41e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“glyphosate and 2,4-D, sold under 55 and 41 different brand names, respectively”
t0“rice”
Claim · model-written summary
Market prices for glyphosate and 2,4-D were below the average herbicide price of US $17 ha−1.
- Taxon
- riceOryza sativat0
- Outcome
- relatively competitive pricese0
- Value
- US $17 ha−1e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“at relatively competitive prices (below average herbicide price of US $17 ha−1)”
t0“rice”
Claim · model-written summary
Glyphosate and 2,4-D were the most popular herbicides among farmers.
- Taxon
- riceOryza sativat0
- Outcome
- most popular herbicides among farmerse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“They are also the most popular herbicides among farmers”
t0“rice”
Claim · model-written summary
Fewer than 23% of farmers received herbicide advice from extension services.
- Taxon
- riceOryza sativat0
- Outcome
- advice from extension servicese0
- Value
- <23%e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“only a few receive advice from extension services (<23%)”
t0“rice”
Claim · model-written summary
Fewer than 16% of farmers read the product label for advice.
- Taxon
- riceOryza sativat0
- Outcome
- reading the product labele0
- Value
- <16%e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“inform themselves by reading the product label (<16%)”
t0“rice”
Claim · model-written summary
Herbicide application timing was suboptimal in 38% of cases.
- Taxon
- riceOryza sativat0
- Outcome
- Herbicide application timings are therefore often (38%) sub-optimale0
- Value
- 38%e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Herbicide application timings are therefore often (38%) sub-optimal”
t0“rice”
Claim · model-written summary
The authors recommend stricter pesticide regulation, research and service provision to improve weed management.
- Taxon
- riceOryza sativat0
- Outcome
- strict implementation and monitoring of national pesticide regulations and investment in research and development to innovate and diversify the currently followed weed management strategies, agricultural service provision and communications with farmerse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Moving away from this status quo will require strict implementation and monitoring of national pesticide regulations and investment in research and development to innovate and diversify the currently followed weed management strategies, agricultural service provision and communications with farmers”
t0“rice”
The same questions in other papers
herbicide · yield · Oryza sativa (rice)Positive and negative results
724 papers in the same direction as this paper · 57 in the opposite direction · 20 reporting no difference from an alternative
- positive
- positive
- positive
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