By Blake Jackson
Plant Science PhD student Noelle Connors is researching whether changes in corn planting practices can reduce the need for herbicides in dairy farming systems.
According to Penn State Extension, many Pennsylvania dairy producers use a double-cropping system that includes corn silage followed by winter small-grain silage.
Weed control in these systems typically depends heavily on herbicide applications, but Connors is evaluating alternative approaches that rely more on crop competition.
Connor's research focuses on a new generation of short-stature corn hybrids. Previous studies suggested that planting corn at higher populations in narrower rows can help suppress weeds by creating more shade and limiting the sunlight available for weed growth.
However, traditional corn hybrids often lodge, or fall over, when planted at high densities, reducing yields. Short-stature hybrids are designed to resist lodging, making dense planting more practical.
To evaluate the approach, Connors compared short-stature and conventional corn hybrids under different management strategies, including high plant populations and narrow 15-inch row spacing versus the standard 30-inch rows.
The study also introduced three problematic weed species, burcucumber, common cocklebur, and Palmer amaranth, into research plots at various stages to simulate different weed emergence scenarios.
Researchers measured weed biomass, seed production, corn silage yield, and forage quality. They also monitored light penetration, soil moisture, and soil temperature to better understand how the planting systems influenced field conditions.
The results showed that higher plant populations generally improved silage yields, while differences in forage quality remained minimal. Weed emergence timing played a major role in weed growth, with later-emerging weeds producing significantly less biomass and fewer seeds.
The combination of narrow rows and high plant populations provided the strongest weed suppression.
"This practice has the potential to reduce weed biomass and seed production by up to 99% depending on species, emergence timing, and environmental conditions," Connors said.
The research aligns with regenerative agriculture principles by using crop competition instead of chemical controls to manage weeds. Conducted within a no-till, double-cropping system and supported by dairy manure as a primary nitrogen source, the approach aims to reduce input costs, improve soil health, and lower environmental risks.
The findings suggest that short-stature corn hybrids, when paired with strategic planting practices, could help farmers maintain strong yields while reducing dependence on herbicides.
Photo Credit: gettyimages-luc-pouliot
Categories: Pennsylvania, Crops, Corn