Nitrogen balance and gap of a high yield tropical soybean crop under irrigation

Author(s)

Zambon, Leandro Moraes ; Umburanas, Renan Caldas ; Schwerz, Felipe ; Sousa, Jackellyne Bruna ; Barbosa, Everton Servilho Teixeira ; Inoue, Leticia Pacheco ; Dourado-Neto, Durval ; Reichardt, Klaus

• Document type: Journal article
• Source: FRONTIERS IN PLANT SCIENCE; v. 14, p. 12-pg., 2023-09-27.

Abstract

Nitrogen (N) is the most extracted and exported element by the soybean crop. In high yield tropical environments with irrigation, little is known about N accumulation in different soybean plant organs as well as the N balance. The objective of this study was to characterize soybean growth, N accumulation in plant organs, N balance, and N gap in a high yield tropical environment. This study was performed in a homogeneous field, in a soil with low organic matter, with 20 kg ha-1 of N, under furrow fertilization. Evaluations were performed ten times, temporally distributed from emergence to senescence. The soybean cultivar used was 'RK7518 IPRO' and was sown with row spacing of 0.45 m and a seeding rate of 300,000 plants ha-1. Plant N partition, N from the biological N fixation (BNF), grain yield, crop harvest index (HI), N harvest index (NHI) with and without root contribution were evaluated. Also, at the grain filling stage the N gap was evaluated from the soil by difference between whole plant accumulated N and the amount of N from BNF. The average grain yield was 6,470 kg ha-1 and leads to a negative partial balance of N of -33.4 and -42.8 kg[N] ha-1 with and without roots, respectively. The N gap from the soil was 231.7 kg[N] ha-1. It is recommended to adopt techniques that increase the efficiency of BNF and the soil N accumulation to balance these production systems in the medium to long term. (AU)

• FAPESP's process: 16/06310-0 - How breeding of soybean cultivars modified morphophysiological attributes of plants?
• Grantee: Renan Caldas Umburanas
• Support Opportunities: Scholarships in Brazil - Doctorate