International Food Policy Research Institute (IFPRI), Washington, DC, United States of America.
DiSSE-Department of Social Sciences and Economics, Sapienza University of Rome, Rome, Italy.
PLoS One. 2022 Mar 25;17(3):e0265947. doi: 10.1371/journal.pone.0265947. eCollection 2022.
We examine the association between on-farm production diversity on household dietary diversity in Malawi using microdata collected as part of an environmentally sustainable agricultural intensification program. The program primarily focuses on the integration of legumes into the cropping system through maize-legume intercropping and legume-legume intercropping. Relative to staple cereals such as maize, legumes are rich in micronutrients, contain better-quality protein, and lead to nitrogen fixation. Given the systematic difference we document between program beneficiaries and randomly sampled non-beneficiary (control) households, we employ causal instrumental variables mediation analysis to account for non-random selection and possible simultaneity between production and consumption decisions. We find a significant positive treatment effect on dietary diversity, led by an increase in production diversity. Analysis of potential pathways show that effects on dietary diversity stem mostly from consumption of diverse food items purchased from the market made possible through higher agricultural income. These findings highlight that, while increasing production for markets can enhance dietary diversity through higher income that would make affordable an expanded set of food items, the production of more nutritious crops such as pulses may not necessarily translate into greater own consumption. This may be due to the persistence of dietary habits, tastes, or other local factors that favor consumption of staples such as maize and encourage sales of more profitable and nutritious food items such as pulses. Pulses are a more affordable and environmentally sustainable source of protein than animal source food, and efforts should be made to enhance their nutritional awareness and contribution to sustainable food systems and healthier diets.
我们利用作为环境可持续农业强化计划一部分所收集的微观数据，考察了马拉维农场生产多样性与家庭饮食多样性之间的关系。该计划主要侧重于通过玉米-豆类间作和豆类-豆类间作将豆类纳入种植系统。与玉米等主食相比，豆类富含微量营养素，含有更高质量的蛋白质，并能固定氮。鉴于我们记录的计划受益人与随机抽样的非受益（对照）家庭之间存在系统性差异，我们采用因果工具变量中介分析来解释生产和消费决策之间的非随机选择和可能的同时性。我们发现饮食多样性有显著的正处理效应，这主要是由生产多样性的增加所导致的。对潜在途径的分析表明，饮食多样性的影响主要源于通过更高的农业收入从市场购买的多样化食品的消费。这些发现强调，虽然增加市场生产可以通过更高的收入来提高饮食多样性，从而使更多的食品种类变得负担得起，但种植更有营养的作物，如豆类，不一定会导致自身消费的增加。这可能是由于饮食习惯、口味或其他有利于消费玉米等主食的本地因素的持续存在，以及销售更有利可图和更有营养的食品，如豆类的鼓励。豆类是比动物源食品更实惠和更可持续的蛋白质来源，应努力提高人们对豆类的营养认识，并促进其对可持续粮食系统和更健康饮食的贡献。
