一项研究说,多样化的谷物种植可能有助于增强非洲的可持续粮食安全。许多非洲国家面临粮食短缺,这部分是由于正在退化的生态系统带来的农业生产力的下降。Sieglinde S. Snapp及其同事探索了种植豆类植物的作物多样化而非单一栽培是否能为马拉维带来可持续谷物生产,马拉维是一个总体说来有1300万人口的贫困国家,一些人把它称赞为非洲绿色革命的诞生地。
政府对化肥和优良玉米种子的补贴已经让马拉维无数农民的生产力取得了显著收益。但是广泛存在的单一种植玉米的做法,再加上该国对富含热量的食品的不断增长的需求,已经在无意之间导致了与单一栽培有关的农业生产力的不稳定。
这组作者既进行了一场多样化玉米种植的全国范围试验,也进行了旨在了解农民对多样化农业的评估的参与式研究项目。这组作者发现,间作和轮作灌木状的豆科植物能帮助增加固氮,减少对化肥的需求,并增加有营养的谷物的产量。这组作者说,这些发现提示,多样化的谷物种植可能帮助提高非洲的粮食和环境安全。(生物谷Bioon.com)
生物谷推荐英文摘要:
PNAS doi: 10.1073/pnas.1007199107
Biodiversity can support a greener revolution in Africa
Sieglinde S. Snappa,1, Malcolm J. Blackieb, Robert A. Gilbertc, Rachel Bezner-Kerrd, and George Y. Kanyama-Phirie
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.