Abstract
The Asian green revolution trebled grain yields through agrochemical intensification of monocultures. Associated environmental costs have subsequently emerged. A rapidly changing world necessitates sustainability principles be developed to reinvent these technologies and test them at scale. The need is particularly urgent in Africa, where ecosystems are degrading and crop yields have stagnated. An unprecedented opportunity to reverse this trend is unfolding in Malawi, where a 90% subsidy has ensured access to fertilization and improved maize seed, with substantive gains in productivity for millions of farmers. To test if economic and ecological sustainability could be improved, we preformed manipulative experimentation with crop diversity in a countrywide trial (n = 991) and at adaptive, local scales through a decade of participatory research (n = 146). Spatial and temporal treatments compared monoculture maize with legume-diversified maize that included annual and semiperennial (SP) growth habits in temporal and spatial combinations, including rotation, SP rotation, intercrop, and SP intercrop systems. Modest fertilizer intensification doubled grain yield compared with monoculture maize. Biodiversity improved ecosystem function further: SP rotation systems at half-fertilizer rates produced equivalent quantities of grain, on a more stable basis (yield variability reduced from 22% to 13%) compared with monoculture. Across sites, profitability and farmer preference matched: SP rotations provided twofold superior returns, whereas diversification of maize with annual legumes provided more modest returns. In this study, we provide evidence that in Africa, crop diversification can be effective at a countrywide scale, and that shrubby, grain legumes can enhance environmental and food security.
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Claims 8
Claim · model-written summary
Modest fertilizer intensification doubled grain yield relative to monoculture maize.
- Treatment
- Modest fertilizer intensificatione0
- Outcome
- grain yielde0
- Direction
- doublede0
- Comparator
- monoculture maizee0
Zea maysOrganisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Modest fertilizer intensification doubled grain yield compared with monoculture maize.”
Claim · model-written summary
Semiperennial rotation at half fertilizer rates produced grain yields equivalent to monoculture.
- Treatment
- SP rotation systems at half-fertilizer ratese0
- Outcome
- quantities of graine0
- Direction
- equivalente0
- Comparator
- monoculturee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“SP rotation systems at half-fertilizer rates produced equivalent quantities of grain, on a more stable basis (yield variability reduced from 22% to 13%) compared with monoculture.”
t0“monoculture maize with legume-diversified maize”
Claim · model-written summary
Semiperennial rotation reduced maize yield variability from 22% to 13% relative to monoculture.
- Treatment
- SP rotation systems at half-fertilizer ratese0
- Outcome
- yield variabilitye0
- Direction
- reducede0
- Value
- 22% to 13%e0
- Comparator
- monoculturee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“SP rotation systems at half-fertilizer rates produced equivalent quantities of grain, on a more stable basis (yield variability reduced from 22% to 13%) compared with monoculture.”
t0“monoculture maize with legume-diversified maize”
Claim · model-written summary
Semiperennial rotations provided twofold superior returns across sites.
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Across sites, profitability and farmer preference matched: SP rotations provided twofold superior returns”
t0“monoculture maize with legume-diversified maize”
Claim · model-written summary
Annual legume diversification of maize provided more modest returns.
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“diversification of maize with annual legumes provided more modest returns.”
Claim · model-written summary
Profitability and farmer preference matched across sites.
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Across sites, profitability and farmer preference matched”
t0“monoculture maize with legume-diversified maize”
Claim · model-written summary
The authors conclude that crop diversification can work at countrywide scale in Africa.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“in Africa, crop diversification can be effective at a countrywide scale”
t0“monoculture maize with legume-diversified maize”
Claim · model-written summary
The authors conclude shrubby grain legumes can enhance environmental and food security.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“shrubby, grain legumes can enhance environmental and food security.”
t0“monoculture maize with legume-diversified maize”
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See all 3,908 papers →Claims are grouped by organism, treatment and what was measured or targeted. A paper counts as positive when any of its claims in the group is positive.