Higher yields and more biodiversity on smaller farms

Small farms constitute most of the world’s farms and are a central focus of sustainable agricultural development. However, the relationship between farm size and production, profitability, biodiversity and greenhouse gas emissions remains contested. Here, the authors synthesize current knowledge through an evidence review and meta-analysis and show that smaller farms, on average, have higher yields and harbour greater crop and non-crop biodiversity at the farm and landscape scales than do larger farms. They find little conclusive evidence for differences in resource-use efficiency, greenhouse gas emission intensity and profits. Their findings highlight the importance of farm size in mediating some environmental and social outcomes relevant to sustainable development. They identify a series of research priorities to inform land- and market-based policies that affect smallholders globally.