How early weed pressure affects crop yield before plants even emerge

"As a seedling comes through the ground, as it gets close to the soil surface, it can detect what's above it through light signals. It can actually change how its growth pattern develops before it's even out of the ground. That early detection triggers a cascade of internal responses, producing elevated levels of singlet oxygen - a reactive molecule associated with plant stress."

"It's like saying the ship is on fire. The plant has to expend energy to control that fire before it can continue on. Neighbouring weeds can suppress photosynthetic genes and reduce chlorophyll production, while increasing the plant's antioxidant activity to manage internal stress, reducing the crop's resilience to additional pressures such as drought, insects, or disease."

"If weeds are present early and another stress comes along - like drought - that can become the perfect storm. That's another argument for why early-season weed control is critical for protecting crop yield and resilience against multiple environmental pressures."

Crops possess the ability to sense neighboring weeds extremely early through light signals, even before breaking through the soil surface. This early detection triggers internal stress responses, including elevated levels of singlet oxygen, forcing plants to divert energy away from growth to manage stress rather than toward yield development. The presence of weeds suppresses photosynthetic genes, reduces chlorophyll production, and increases antioxidant activity, compromising crop resilience. When early weed pressure combines with additional stressors like drought, insects, or disease, the compounded effects create severe yield losses. This research demonstrates that traditional competition for water, nutrients, and sunlight occurs much later than previously understood, making early-season weed control critical for crop success.

Read at Realagriculture