Insufficient nitrogen supply from symbiotic fixation reduces seasonal crop growth and nitrogen mobilization to seed in highly productive soybean crops

Authors

Nicolas Cafaro La Menza, University of Nebraska-LincolnFollow
Juan Pablo Monzon, University of Nebraska–Lincoln & National Scientific and Technical Research Council (CONICET)Follow
John L. Lindquist, University of Nebraska-LincolnFollow
Timothy J. Arkebauer, University of Nebraska - LincolnFollow
Johannes M.H. Knops, University of Nebraska - Lincoln & Xi'an Jiaotong Liverpool UniversityFollow
Murray Unkovich, The University of AdelaideFollow
James E. Specht, University of Nebraska-LincolnFollow
Patricio Grassini, University of Nebraska-LincolnFollow

ORCID IDs

Patricio Grassini https://orcid.org/0000-0002-7501-842X

Date of this Version

2020

Citation

Cafaro La Menza N, Monzon JP, Lindquist JL, et al. Insufficient nitrogen supply from symbiotic fixation reduces seasonal crop growth and nitrogen mobilization to seed in highly productive soybean crops. Plant Cell Environ. 2020;43:1958–1972. https://doi.org/10.1111/ pce.13804

Comments

2020 The Authors. This is an open access article under the terms of the Creative Commons Attribution-NonCommercial-NoDerivs License

Abstract

Nitrogen (N) supply can limit the yields of soybean [Glycine max (L.) Merr.] in highly productive environments. To explore the physiological mechanisms underlying this limitation, seasonal changes in N dynamics, aboveground dry matter (ADM) accumula- tion, leaf area index (LAI) and fraction of absorbed radiation (fAPAR) were compared in crops relying only on biological N2 fixation and available soil N (zero-N treatment) versus crops receiving N fertilizer (full-N treatment). Experiments were conducted in seven high-yield environments without water limitation, where crops received optimal management. In the zero-N treatment, biological N2 fixation was not sufficient to meet the N demand of the growing crop from early in the season up to beginning of seed filling. As a result, crop LAI, growth, N accumulation, radiation-use efficiency and fAPAR were consistently higher in the full-N than in the zero-N treatment, leading to improved seed set and yield. Similarly, plants in the full-N treatment had heavier seeds with higher N concentration because of greater N mobilization from vegetative organs to seeds. Future yield gains in high-yield soybean production systems will require an increase in biological N2 fixation, greater supply of N from soil or fertilizer, or allevia- tion of the trade-off between these two sources of N in order to meet the plant demand.