Nitrogen Supply Affects Soybean Yield Differently Within the Canopy

Soybean, the most cultivated legume in the world, is influenced by the seasonal availability of resources. One of the most important resources is nitrogen (N), which is becoming a yield-limiting factor in fields with high yield potential due to an asynchrony between N supply (biological N fixation and soil N) and demand. Despite N being one of the most important nutrients for soybean, it is unknown how N availability influences seed yield (i.e., seed number, pod number, seeds per pod, and individual seed weight) across the soybean canopy.

Researchers evaluated nine high-yielding irrigated soybean fields in Nebraska under two treatments: Zero-N (no additional N application, relying on soil N and microbes that “fix” atmospheric N into usable N) and Full-N (ample N supply).