Ames, Iowa, USA
Doctoral student Amina Moro's work focuses on how corn responds to nearby perennial groundcover, a system gaining attention for its ability to protect soil year-round.
At Iowa State University, Amina Moro is advancing research that could reshape how farmers balance productivity with environmental sustainability.
A doctoral student in crop production and physiology, Moro’s work focuses on how corn responds to nearby perennial groundcover, a system gaining attention for its ability to protect soil year-round. Her paper, “Spatial Proximity to Perennial Groundcover Triggers Shade Avoidance Responses in Corn,” was recently published in the Journal of Agronomy.
“Perennial groundcover systems are very promising because they keep the soil covered year-round, improving soil health, reducing erosion and enhancing sustainability,” Moro said. “But farmers are hesitant to adopt them because of concerns about competition with corn, especially early in the season.”
Her research challenges a common assumption, that competition between plants begins only when they compete for water or nutrients. Instead, she found that competition may start much earlier, through light signals that plants use to detect nearby neighbors.
At the center of Moro’s study is a concept called shade avoidance response. In simple terms, plants can “sense” when other plants are nearby even before they are physically shaded.
“When corn detects changes in light quality, it interprets it as a sign that competition is approaching,” Moro said. “It responds by growing taller and reallocating energy toward vertical growth.”
An experimental unit consisting of two strips of grass and three pots of single corn plants. The corn and grass root zones were physically isolated using separate containers on a 25x50 cm tray, with three corn pots and grass strips positioned at assigned distances (0, 6 and 25 cm) along the tray edges to establish different aboveground competition patterns.
While this might sound beneficial, it comes at a cost. Taller plants often develop thinner stems and reduced structural strength, which can lead to lodging and reduced efficiency later in the season.
One of the most significant findings from Moro’s study is that proximity, not just the presence of groundcover, determines how corn responds.
“We observed that corn begins to respond at very short distances,” she said. “At six centimeters, plants already initiated a shade avoidance response, but at 25 centimeters, they behaved as if there were no competition.”
Even more striking, when corn was in direct contact with groundcover, the stress reduced growth entirely.
This insight has important implications for how cropping systems are designed. Rather than eliminating groundcover, farmers may simply need to adjust spacing.
According to Moro’s advisor, Susana Goggi, professor of agronomy, this research addresses one of the most pressing challenges in modern agriculture: balancing soil health with crop productivity.
“The use of perennial groundcover is a game-changer,” Goggi said. “It can reduce soil erosion, water runoff and nutrient loss. But it also creates microclimatic changes that can affect crop growth.”
Moro’s work is helping identify the “sweet spot,” the ideal distance between crops and groundcover that preserves environmental benefits without sacrificing yield.
The practical applications of this research are clear. By maintaining a small buffer zone – around 25 centimeters – farmers can prevent early stress signals in corn while still benefiting from soil protection.
Moro’s findings also highlight the importance of hybrid selection. Some corn varieties are more sensitive to shade signals than others, meaning farmers can further optimize performance by choosing the right genetics.
“Farmers do not have to choose between improving soil health and maintaining yield,” Moro said. “With the right combination of spacing, hybrid selection and management practices, it is possible to design systems where corn grows efficiently while the soil remains protected.”
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