Soybean seed protein concentration is limited by nitrogen supply in tropical and subtropical environments in Brazil

Authors

E. H. Figueiredo Moura da Silva, University of São Paulo
N. Cafaro La Menza, University of Nebraska-LincolnFollow
G. G. Munareto, Federal University of Santa Maria
A. J. Zanon, Federal University of Santa Maria
Santos Carvalho, Federal Institute of Mato Grosso
F. R. Marin, University of São Paulo

Document Type

Article

Date of this Version

2-22-2023

Citation

Journal of Agricultural Science. DOI: 10.1017/S0021859623000199

Comments

Used by permission.

Abstract

Soybean production contributes to ca. 60% of global plant-based protein used for food and feed. Brazil is the largest soybean producer and exporter, with 60% from tropical and 40% from subtropical environments. Nitrogen (N) can play an essential role in the storage of proteins in seeds; thus, it could be a key factor in increasing the quantity and quality of seeds in high-yielding soybean crops. Unlike in temperate environments, there is a gap of knowledge on whether soybean grown under tropical and subtropical climates are limited by N-fertilization to sustain the seed yield increase without detriments in seed protein concentration. This study aimed to evaluate the effect of N-fertilization on soybean seed yield, protein, and oil concentrations in tropical and subtropical environments in Brazil, thus contributing to agricultural intensification procedures and food security studies. Two levels of N-fertilization (0 and 1000 ka/ha) were tested across 11 tropical or subtropical environments. The range of latitudes explored here was from 12º S to 29º S, representing the major soybean-producing regions in Brazil either under rainfed or irrigated conditions. We found that seed yield responses to N-fertilization were significant (in some environments under rainfed with an average increase of 7%) or not significant (in irrigated). Seed protein increases due to improved N-fertilization (on average 4% for irrigated and 12% for rainfed conditions) were much higher than previous reports from temperate environments. Regardless of N supply and water deficit, there was a trend of seed protein and oil concentration increasing toward lower latitudes.