By Andi Anderson
Iowa State University graduate student Ally Larson has won top recognition from the Midwest Cover Crop Council for her unique research on how plant inputs affect soil. Her winning poster, presented at the council’s annual meeting in Minnesota, featured findings from the Agricultural DIRT (Detritus Input and Removal Treatments) study.
The project, conducted at Iowa State’s Boone research farm, tested how cereal rye—used as a cover crop—affects soil and neighboring cash crops like corn and soybeans. Larson helped set up 288 small plots with four treatments: no cover crop, roots only, shoots only, and both roots and shoots. These plots were carefully monitored throughout the growing season.
To compare how quickly different plant parts decomposed, the roots-only and shoots-only plots also included small mesh bags filled with rye grown in a greenhouse. These bags were collected weekly to track decomposition. “Our early results showed that biomass and decomposition rates were similar, even though soil temperature and moisture levels varied,” said Larson. “That was surprising.”
Larson, who is studying crop physiology and soil science, is guided by Marshall McDaniel, associate professor of agronomy. He praised her commitment: “She started in our lab as an undergrad and now plays a key leadership role.”
A unique feature of their work includes the development of a soil dendrogram—visual soil mapping using deep soil cores. Larson plans to expand this part of the study in her master’s thesis.
Their findings add to a global network of DIRT studies, though this is believed to be the first one focused on farming systems. The research is funded by USDA’s National Institute for Food and Agriculture and the Iowa Nutrient Research Center.
“The mix of lab work, fieldwork, and analysis is exactly why I stayed at Iowa State for grad school,” said Larson. “It’s been a great decision.”
Photo Credit: iowa-state-university
Categories: Iowa, Education