Matthew Longmire grew up on his family farm in Clinton, TN, so it was no surprise that he became interested in research on agricultural systems. The fact that he can do this while incorporating another life-long fascination—bugs—is just the icing on the cake.
“I’ve known since I was extremely little—before I even knew the word entomology—that I wanted to do something with bugs,” Longmire said. “I’ve had a bug collection since I was about 4 years old.” Longmire, a graduate student in entomology and plant pathology at the UT Institute of Agriculture, researches the impact of cover crops on agricultural pest management. Farmers use cover crops to cover the soil between the growing seasons of cash crops like soybeans and corn. These plants, which include clovers, mustards, and grasses, play an essential role in improving soil health by reducing erosion, improving water filtration, and managing soil nutrients. This practice is increasing in agriculture because it can reduce the need for chemical fertilizers and herbicides, which can lower costs and increase profits.
In addition to the soil amendment services provided by cover crops, their potential role in pest management is an emerging topic in agricultural science. By paying attention to species selection, placement, and timing, cover crops may have the ability to reduce infestations by insects, diseases, nematodes, and weeds. Pest-fighting cover crop systems could help minimize reliance on chemical pesticides, and as a result, provide additional cost savings.
Farming and forestry dominate Tennessee’s landscape with 66,600 farms producing and selling crops, livestock, and forest products. Forty percent of the state’s land area is farmland. Soybeans, in particular, play an important role in Tennessee’s agricultural production. They are planted on more acres than any other row crop in the state and generate over $655 million in cash receipts.
Longmire’s research compares how selecting cover crops affects the composition and density of different arthropods, a classification that includes insects, arachnids, and crustaceans. His study focused on the most popular cover crop species—grasses, mustards, and legumes—for soybeans.
Traditionally, cover crops are mowed or treated with herbicides prior to developing the soil for cash crops. However, dual-use cover crops can yield an alternate revenue stream for farmers by providing an agricultural product. Grasses, such as rye and wheat, for example, can be used for livestock forage. Longmire’s research compares the difference in arthropod communities between plots that killed the cover crops prior to planting and those that harvested the cover crop for sale.
Although he did not find that one group of cover crops was more effective than another at reducing pest infestations in the cash crop, Longmire did find that each cover species had a unique composition of arthropods. He says that with a better understanding of cover crop-arthropod interactions, Tennessee’s soybean farmers can make more informed, region-specific decisions about which cover crops are right for their system.
Longmire’s research is part of a new approach to a farm as an agroecosystem—a dynamic relationship of the mineral, biological, weather, and human resources involved in producing crops or livestock. Studying agricultural practices that are environmentally sound and economically feasible can ensure the sustainability of Tennessee’s farming industry for generations to come.