14.05.2021 |

Small farms have higher yields and more biodiversity, study finds

Small farms have more biodiversity (Photo: CC0)

Smaller farms have higher yields and biodiversity than their larger counterparts, new research suggests. According to a study published in the journal “Nature Sustainability”, smallholders are “both productive and stewards of biodiversity” and their profit per hectare is similar to larger operations, the scientists from the University of British Columbia (UBC) found. “Small farms constitute most of the world’s farms and are a central focus of sustainable agricultural development,” the authors write. 84% of farms are less than 2 hectares in size and those farms produce a third of the world’s food, they added. “However, the relationship between farm size and production, profitability, biodiversity and greenhouse gas emissions remains contested.” For this reason, they looked at the current state of knowledge and found 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. Thus, investing in smallholders could lead to humanitarian benefits but also to increases in food production and benefits to biodiversity, they concluded.

The researchers conducted a meta-analysis. “Our initial search resulted in 1474 studies, of which 118 met our inclusion criteria and yielded 318 observations for analysis”, explains author and UBC professor Navin Ramankutty. The team analysed studies from 51 countries on the relationship between relative farm size and yields, crop diversity, non-crop biodiversity at field and landscape levels, resource-use efficiency, greenhouse gas emissions per unit output, and profit per unit area. “In our paper, we synthesize data from studies that have been conducted on this question over the last 50 years,” Ramankutty said. For crop diversity and greenhouse gas emissions, there were too few literature samples to conduct a meta-analysis and the authors simply reported on a previously conducted analysis of crop diversity relationships with farm size based on census and household survey data. With respect to yields, they found that smaller farms have higher yields. 79% of the studies reviewed reported that smaller farms have higher yields measured either in terms of weight per hectare or in crop value per hectare. “We also find that yields typically decrease by 5% for each hectare increase in farm size”, they write. “This is not an altogether surprising result – the inverse farm size-productivity relationship has fascinated agricultural economists for nearly a century.”

The study also found that non-crop biodiversity increases with decreasing farm size, with 77% of studies finding that smaller farms have greater biodiversity at both farm and landscape scales. “The primary studies we reviewed suggest that this is because of more ecological management practices on smaller farms (lower pesticide use, organic management, etc.), edge effects (smaller farms having larger margins that support biodiversity), or more diverse land cover in small-farming dominated landscapes,” Ramankutty explains in a background article to the paper. The authors found that increased field edges can lead to larger available breeding habitats for arthropods, provide refuge for arthropods and smaller species to colonize after escaping recently disturbed fields, increase the number of pollinators and beneficial predators within fields and act as conservation corridors for arthropods and small mammals. The researchers also showed that smaller farms have greater crop diversity. They found that, except for an unexplained dip in the 2–5 ha size range, there is a strong inverse relationship globally between farm size and the number of crop species found across the landscape – with higher species diversity on small farms than larger farms when controlling for area.

The study presented no conclusive evidence for a relationship between farm size and resource-use efficiency, greenhouse gas emissions, or profitability, even though the majority of studies concluded that larger farms had greater resource efficiency than smaller farms. With regard to profit, conclusions were limited since the researchers only had 15 observations. For certain smallholder-dominant countries (for example, India and Ethiopia), the authors found that smaller farms were more profitable, whereas larger farms were more profitable in countries dominated by large farms, higher incomes, and better rural infrastructure, such as the US. Small farms were also more profitable when they engaged in niche, high-value markets, for example, export-oriented producers with fair trade or environmental certification. But some studies also showed that even though smaller farms had greater profits per hectare, their absolute levels of production were often too low to maintain viable livelihoods. “So we looked at profit per area, and yeah, they were equal,” lead author Vincent Ricciardi told Canada’s “National Observer”. “But then if you were to divide that amongst all your workers, and you have a lot more workers because all your family is helping you and everything, it's still probably not enough to truly be profitable per person,” he said.

The authors underline the need for increased policy support for smaller farms. “While smaller farms have benefits, smallholders are finding it challenging to make a living from agriculture,” summarizes Ramankutty. “Our study shows that smallholders are both productive and stewards of biodiversity. Rewarding smaller farms for their conservation benefits may be one policy pathway towards supporting smallholders.” The authors explain that their findings come at a time where donor countries need to invest an estimated US$14 billion annually to achieve the goal of Sustainable Development Goal 2.3 to double the incomes and productivity of smallholders. “Our review adds to the motivation for these investments,” they write. “Development support for smallholders is imperative from multiple viewpoints: the data not only show that investing in smallholders could lead to humanitarian benefits but also to increases in food production and benefits to biodiversity.” (ab)

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