Ryan teaches Cover Crops in Agroecosystems, in which students learn about the benefits and logistics of planting cover crops, like legumes and grasses, in between cash crop plantings. The practice sequesters carbon dioxide, improves long-term soil fertility and reduces soil erosion – especially important as the changing climate increases the frequency and intensity of extreme rainfall events.
“Cover crops are one of the primary ways that farmers can increase the sustainability of their cropping systems,” Ryan said. “This conservation practice offers ecological benefits, like supporting beneficial insects and reducing water pollution, and it often results in higher yields over time for farmers because of improved soil health.”
The class is one of over 40 that enrich student learning by hosting experiential activities at the research farms and greenhouses managed by the Cornell University Agricultural Experiment Station (Cornell AES).
One of Ryan’s most impactful activities is the “Cover Crop Challenge.” Students get to choose from among 12 different species, such as crimson clover, annual ryegrass, mustard and oats, to create their own cover crop mixtures. They then plant their mixtures indoors, in one of the Cornell AES greenhouse facilities, and outdoors, in the Crops Garden at Campus Area Farms. Eight weeks later, students take a host of measurements to assess the effectiveness of their cover crops – insect and floral diversity, total biomass, weed suppression and more – and they calculate the economic efficiency of their mixtures.
Ryan developed the Cover Crop Challenge as a teaching activity in 2013 for his class Sustainable Agriculture: Food, Farming, and the Future (PLSCI 1900), which will be offered again in fall 2025. Between 2021-2023, Ryan worked with colleagues at universities across the country to teach a multi-institutional course Cover Crops in Agroecosystems (PLSCI 4125/6125), which included the Cover Crop Challenge. Students from Cornell, Clemson University, Michigan State University, University of Nebraska–Lincoln, University of New Hampshire and University of Kentucky competed against each other to grow cover crops that were the biggest and most economical. A Dec. 2024 journal article about the Cover Crop Challenge, co-authored by Ryan and 10 colleagues, explores the benefits of the learning activity and offers a guide for others interested in using it.
Natasha Djuric, a graduate student in Ryan’s lab, took PLSCI 4125 in Fall 2022 and co-authored the new article.
“The most impactful thing for me was learning what different people choose to prioritize,” Djuric said. Some students were most concerned with carbon sequestration or preventing soil erosion, while Djuric’s top priority was growing the most flowers to feed pollinators. Students from farming families often prioritized oats, because they knew they were cheap to plant and would grow quickly, she said.
“What we prioritize is a really big factor in deciding which cover crops to use, or whether to use cover crops at all,” she said. “In trying to promote cover crop adoption, it’s really important to see other people’s perspectives.”
For Sharifi, the course brought together complementary elements of key challenges he wants to help address: climate change and agricultural sustainability.
“I came into Cornell focused on the environment and sustainability, but I fell in love with ag, in part because I realized how important ag is for sustainability,” he said. “We have a growing population of 8 billion people, and we need to address problems like climate change and herbicide resistance – modern ag is facing an onslaught of these problems. We haven’t seen a revolution in agriculture since the Green Revolution, and we’re due for another one. I want to be part of that.”
Source : cornell.edu