Soybean seed yield distribution within the canopy as affected by nitrogen supply

Abstract Soybean ( Glycine max [L.] Merr.) seed yield is influenced by the seasonal availability of resources (i.e., nutrients, light, and water). While nitrogen (N) supply is becoming a soybean yield‐limiting factor, the N‐induced effect in seed yield components is still unclear. The objective of this research was to assess the effect of N supply on soybean yield components distribution within the canopy. A ‘Full‐N’ treatment, which provided the crop with ample N supply, was compared against a ‘Zero‐N’ treatment in which the crop relied on soil N and biological N fixation at nine high‐yielding irrigated soybean environments in Nebraska, with known levels of N limitation. Soybean seed yield components were determined at every node and grouped into five canopy sections. Seed yield ranged from 4378 to 7314 kg ha −1 across environments and treatments. The greater N availability in the Full‐N increased yield by 984 kg ha −1 in comparison to Zero‐N; via +253 seeds m −2 (7%) and +16 mg seed −1 (11%). N‐induced responses in seed yield occurred in the lower (nodes 0–4), middle (nodes 9–13), and middle‐upper sections (nodes 13–18). Seed number and pod number increased in the middle‐upper section. Notably, individual seed weight increased in all node sections. The seed number per pod response to N was negligible. The seed abortion within pods was 8%, but the Full‐N treatment reduced it by one percentage point. This study comprehensively examined the effects of N availability on soybean yield components within the canopy during their sequential establishment.