Protect Pollinators, Plant Trees? Nebraska Researchers Look To Land For Answers

Oct 27, 2017
Originally published on November 3, 2017 5:08 am

You don't need bees and butterflies to grow corn and soybeans, but a majority of farmers do rely on pesticides, which don't discriminate between helpful and harmful insects.

The widespread use of pesticides is considered a major factor in the large-scale decline in bee populations in recent years. But it's unlikely farmers will give up or limit pesticide use, so instead, a team of researchers at the University of Nebraska-Lincoln is looking at designing agricultural landscapes with pollinator health in mind.

In other Plains and Midwestern states, researchers are having farmers plant prairie strips between fields to help combat water contamination from pesticides and fertilizer. UNL's five-year project wants to find out whether windbreaks, planted pollinator habitat, cover crops or a combination of those techniques can help limit pesticide drift.

Most commercial corn and soybean seeds have a pesticide coating that can become airborne and drift onto plants that bees rely on, such flowering trees and shrubs that grow along roadsides or in field corners.

Corn planting coincides with spring blooming, according to Judy Wu-Smart, a UNL assistant professor and extension specialist in pollinator health, drawing bees in at a time when they’re even more likely to get pesticide exposure.

There’s a key word in this fight for pollinator health: neonicotinoids. That’s a newer class of insecticides that differ from other pesticides because their toxic chemicals move throughout the entire plant and can collect in the soil, Wu-Smart says.

"So they're useful in agricultural production because they can protect plants from root damaging insects and pests, where spray applications may not reach them," she says. "But they're concerning for pollinators because bees that are foraging on plants that have been contaminated with neonicotinoids can be getting it directly through nectar and pollen."

Neonicotinoids can have a variety of effects on bees, which pollinate everything from apples to almonds to avocados. The insecticides can damage foraging, learning, memory, and cognitive functions "that really inhibit the colony from developing well," Wu-Smart says. They can also affect the queen's ability to lay eggs.

Researchers want to make these pollinator-friendly landscape designs appealing enough to farmers that they'll implement them, according to Gary Bentrup, a research landscape planner at the U.S. Department of Agriculture’s National Agroforestry Center in Lincoln, Nebraska.

"And as a general rule, I find that edge-of-field practices, kind of like what we're suggesting, are usually more palatable (to farmers) than changing an operation in the field," Bentrup says.

He's looking into the role of windbreaks — rows of trees planted along fields that can act as a shield between crops treated with neonicotinoids and pollinator-friendly plants on the other side.

"Evergreens are generally a good choice for that. Their fine leaves and branching structures are effective at trapping pesticide drift," Bentrup says, adding that the roots of the trees can also help filter pesticides in the soil.

But, increasingly, farmers are removing windbreaks to allow for more sprinkler irrigation, which is why Bentrup says it’s important to consider the multiple benefits of landscape design — including economic ones.

"Research has shown that windbreaks can increase corn yields about 13 percent, soybean yields about 15 percent, winter wheat by 23 percent," Bentrup says.

There's also a concerted effort by groups concerned about pollinator survival to establish more habitat, including around farms, Wu-Smart says.

That's why researchers hope to not just examine "what hurts and what harms pollinators but to look at the ecosystem as a whole," she says, and also "look at how we can find that balance between agricultural production and ecosystem functions and beneficial insect communities."

That could be good for farmers and bees.  

Ariana is a reporter for NET News. Follow her on Twitter: @ArianaBrocious

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