Just adding pollinators could boost small-farm yields

Just sending more pollinators into action on small farms around the world could significantly boost crop yields, says a massive new study.

Coaxing more bees, beetles and other pollinators to buzz around small fields could on average boost crop yields enough to close the gap between the worst and the best of these farms by almost a quarter, says agroecologist Lucas Alejandro Garibaldi of the National University of Río Negro and Argentina’s CONICET research network.

This yield gap has excited much interest from people studying the future of the world’s food supply at a time when the explosive growth of the human population needs more, more and even more. Some researchers have estimated that food-growers will need to double agricultural production by 2050 to keep up with the need. “Closing the yield gaps is a key part of the solution, particularly in areas with there’s a poverty trap created by malnourishment, low yields, little income and many other factors,” says Paul West, codirector of the Global Landscape Initiative at the University of Minnesota in Saint Paul.

To see whether improving pollination could make a noticeable difference, Garibaldi and an international network of researchers carefully used the same sampling protocols to observe 344 fields on large and small farms in Africa, Asia and South America over the course of five years. Looking at 33 crops that need pollinators — raspberries, apples, coffee and so on — the researchers monitored pollinator visits and diversity as well as the ultimate yields.

The low-yielding farms on average produced only 47 percent of the yield that the best did, a notable gap. On the small operations, the sheer density of pollinators visiting crop flowers made a bigger difference in the amount of food produced, the researchers found. On larger farms, pollinator diversity mattered more: Those farms with a greater variety of pollinators produced more food.

Analyzing the way yields responded to the number of pollinators shows that improving pollination could help close the yield gap, Garibaldi and his colleagues say in the Jan. 22 Science. The small farms are especially important because more than 2 billion people rely on them for food in developing nations. Farmers can do this by encouraging the natural services that come from a healthy local ecosystem, Garibaldi points out. Growers could plant strips of pollinator-friendly plants beside crop fields, or time pesticide applications to minimize pollinators’ exposure.