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).