Many living creatures live in the soil. One of them is ground-dwelling bees, vital in the pollination cycle of about 90% of plant life. SomeOregon State University researchers study the interaction between bees n soil in an agricultural setting. According to a recently-published paper, bees contribute 15 billion dollars to crop value annually. They pollinate about three-quarters of fruits, vegetables, and nuts within the United States alone. Declines in honeybee colonies are a critical threat to agriculture and the global food supply.
Growers who are interested in attracting wild bees face a significant challenge. There are few studies about what habitats are best for these wild bees. Pollinators are widely affected by human land use. Creating buildings, parking lots, and other “anthropogenic changes “disrupt the natural habitats of animals and plants. Agricultural disturbances also affect bee communities. Occasionally,
growers have been building “bee-bees” in their farm setting. In the 1950s, they started to design moist, salty soil areas to attract bees that helped increase alfalfa yields in Washington state.
Studies looked at the physical n chemical properties of soils collected from active bee and sand nest wasp sites in the Willamette Valley of western Oregon. They compared soil properties among seven farm sites to identify similarities and differences. The Willamette Valley has wet winters with warm summers. The team first found agricultural areas that contained ground-nesting bees. They collaborated with farmers who observed ground-nesting bee activity.
Relatively small holes only identify the nests. The team only collected data if they observed bees entering the nest. Nests can remain alive after the bees leave. At the study site, they classified the type of bee to family level (I.e., Bee versus genus and species. But they also collected some bees to return to the lab for further identification.
Findings from the study included that active nesting sites were present in locations with little to no rock cover and low vegetation. The slope of the land didn’t have any influence, nor did a north-south facing aspect.
One of our observations confirmed that active emergence holes remained open throughout the year. “They didn’t swell shut during the wetter seasons–despite having clay in the soils that might cause shrinking and swelling.
An interesting finding from the research is that the team found lipids in the soil nest linings. The lipids may provide waterproofing for the nests and their inhabitants. “Because most wild bee species nest in the soil, studies about how to best attract them to farms are essential. Soil scientists can partner with growers to identify soil inhabitants that support and attract more of these pollinators to agricultural lands. Improving our understanding of the connection between agriculture and the soil that bees, crops, and living organisms rely on to survive is essential.
Looking to the future, the researcher says, “future research should also integrate methods that identify bees or wasps to a particular level. That would allow for interpretations of the results from an ecological point of view.
This research was published in SOIL SCIENCE OF AMERICA JOURNAL, a publication of the soil science society of America. Funding for this project came from an agricultural research foundation grant via Oregon State University.