Agricultural diversity includes a wide range of aspects, from the ground to the table, and insects and weeds are an important aspect of diversity on the ground that can help improve crop production.
The on-farm aspect of diversification is analyzed by the DCB In-Field Team. Researchers involved in this multidisciplinary collaboration take measurements of soil health, insects, weed communities, and water quality on farms in Iowa, Illinois, and Indiana. DCB Team members work with farmers to understand the big picture of how current agricultural practices affect these areas.
In-Field Team member Ian Kaplan, professor in the Department of Entomology at Purdue University, says there are important and unanswered questions to answer related to insect ecology and conservation.
“A lot of insects are specialists,” Kaplan says. “Entomology has accepted, almost as a truism, this relationship between cropping system diversity and insect diversity, function, community health.”
And, as plants diversify, insects diversify and can provide several types of ecosystem services, actions that provide benefits to humans. The more diversification, the better the ecosystem services. The better the ecosystem services, the more productive agricultural crops can become.
Christine Elliott tracks beneficial insect biodiversity as part of the Diverse Corn Belt Project. This research is crucial for understanding how regenerative practices can enhance ecological health in large-scale commercial agriculture.
Christine Elliott, Ph.D. candidate student in entomology at Purdue University and USDA National Institute of Food and Agriculture (NIFA) Agriculture and Food Research Initiative predoctoral fellow, says that insects are biologically, physiologically, and ecologically diverse.
“Not all processes are going to impact insects to the same extent in the same direction,” Elliott says. “Some insects actually benefit from a little bit of disturbance. Other insects, it’s really negative for them.”
Elliott says that their research is in situ, taking place in the Midwestern farm fields where the researched insects and weeds reside.
“It’s one thing to say, in our little half-acre test plot, here’s what we see,” Elliott says. “but when you’re scaling it up to this 100-, 200-, 300-acre field, it’s hard to say that those half-acre effects that we see are going to scale up. Working in fields of that size is really important, but it does have limitations in terms of the exact variables that we can’t necessarily manipulate or set.”
“Not all processes are going to impact insects to the same extent in the same direction. Some insects actually benefit from a little bit of disturbance. Other insects, it’s really negative for them.”
Elliott’s research focuses on insect inventory using the following three methods:
- Pitfall method: setting out traps for insects to identify crawling insect species, such as ground beetles and ants, and how many
- Acoustic monitoring: recording the sounds of a field and identifying the calling insect species present, such as cicadas, grasshoppers, and katydids
- Soil environmental DNA sampling: using soil sampling to extract DNA and identify the insect taxonomy present
Elliott says she’s analyzing where the three methods converge to see if they complement or contradict one another. So far, she’s seen more than 60 species of ground beetles and 30 species of ants.
Carmen Blubaugh researches weed communities and how they affect crop productivity and relate to insect activity. She’s looking at how plants that are currently seen as weeds provide ecosystem services.
“Diverse rotations typically lead to more diverse weed communities,” she says.
Blubaugh adds that competitive weeds that grow rapidly and evolve herbicide resistance can be mitigated by adding variety to corn and soybean rotations.
“Crop diversification not only limits the domination of the most damaging weed species,” Blubaugh says, “but carves space in agricultural systems for a more diverse community of weeds that tap into separate resources pools from crops and are more compatible with crop productivity.”
And, Blubaugh adds, under some circumstances, those diverse weed communities might actually help, rather than threaten, crops. For example, diverse weeds provide food and habitat for beneficial insects that eat crop pests.
“If diversifying rotations leads to diversity at every level of the food chain,” Blubaugh says, “threats posed to crops by weeds and insect pests could be mitigated, paving the way for a more integrated approach to crop protection.”
Christine Elliott uses a variety of tools to investigate the impact of regenerative agriculture on beneficial insects in agroecosystems.
With their in-situ approach, DCB researchers are learning what insects are doing in the current agricultural landscape. Researchers also gather management information from farmers to try to understand which practices, if any, can be attributed to a variety of ecosystem services.
“We’re asking these questions within a background of incredible environmental noise that you experience from farm to farm,” Blubaugh says. “By having this huge data set, we can start to untangle which of these site characteristics predict increases and enhancements in ecosystem services.”
She adds that patterns emerge from farm to farm when studying insects and weeds in situ.
“Farmers are also key in the picture when we gather data on-farm,” Blubaugh says. “It’s often a powerful co-learning experience when we interact in the field, discuss our research questions, and learn from farmers’ unique experiences and challenges. In-person connections are critical as we proceed with this huge interdisciplinary diversification project.”
The In-Field Team also has learned about farmers’ decision-making processes, as well as the barriers and opportunities farmers have to provide insect habitat.
Elliott says that conservation agriculture practices such as reducing tillage and planting cover crops, as well as reducing pesticide use (including treated seed), can help provide a healthy environment for beneficial insects.
“The goal of the Diverse Corn Belt Project is not just diversification for diversification’s sake,” Elliott says. “It’s because of the idea that from all of these multiple sources that the more diverse it is, the more sustainable it’s going to be.”
Elliott adds that often, benefits like higher yields and uniform produce that are seen in conventional agriculture systems are immediate and seen quickly. However, long-term consequences, such as insect population declines, soil quality losses, water quality decreases, and air quality decrease, need time to surface, and they need to be looked for in order to see them.
“It seems like from the insect side, from the weed side, from the soil health side, we will not be able to keep this up forever,” Elliott says. “By making these systems more sustainable, we will be able to keep it up for longer.”
Blubaugh wants to see the Midwest thrive with locally grown food.
“I’m from Indiana, and I want my home to realize its potential for growing food,” Blubaugh says. “That necessarily means diversifying what we currently grow. The natural outcome of growing things people can eat will be more diverse crops on the landscape.”
See research publications and presentations from the In-Field Team and other DCB Team members on our Publications page.
For the latest news from DCB, sign up for our newsletter!