Understanding N timing in corn yield and fertilizer N recovery: An insight from an isotopic labeled-N determination

Author(s)

de Oliveira, Silas Maciel ^[1] ; Munhoz de Almeida, Rodrigo Estevam ^[2] ; Ciampitti, Ignacio A. ^[3] ; Pierozan Junior, Clovis ^{[1, 4]} ; Lago, Bruno Cocco ^[1] ; Ocheuze Trivelin, Paulo Cesar ^[5] ; Favarin, Jose Laercio ^[1]

Affiliation

^[1] Univ Sao Paulo, Luiz Queiroz Coll Agr, Dept Crop Sci, Piracicaba, SP - Brazil

^[2] Brazilian Corp Agr Res Fishery & Aquiculture, Palmas, Tocantins - Brazil

^[3] Kansas State Univ, Dept Agron, Manhattan, KS 66506 - USA

^[4] Parana Fed Inst Educ Sci & Technol, Palmas, Parana - Brazil

^[5] Univ Sao Paulo, Ctr Nucl Energy Agr, Piracicaba, SP - Brazil

• Document type: Journal article
• Source: PLoS One; v. 13, n. 2 FEB 20 2018.
• Web of Science Citations: 3

Abstract

Early fertilizer nitrogen (N) application on cover crops or their residues during the off-season is a practice adopted in Brazil subtropical conditions under no-tillage corn (Zea mays L.) systems. However, the effect of early N application on yield, plant N content, and N recovery efficiency (NRE) for corn is not yet well documented. Five fertilizer N timings in an oat-corn system were evaluated in two studies utilizing an isotopic-labeled N determination, 15 N isotope. The N fertilization timings were: (i) oat tillering, (ii) 15 days before corn planting time, over the oat residues, (iii) at corn planting time, (iv) in-season at the three-leaf growth stage (V3), and (v) in-season split application at V3 and six-leaf (V6) growth stages. Based on the statistical analysis, the N fertilization timings were separated into three groups: 1) N-OATS, designated to N applied at oat; 2) N-PLANT, referred to pre-plant and planting N applications; and 3) N-CORN, designated to in-season corn N applications. Corn yield was not affected by the N fertilization timing. However, the N-CORN N fertilization timings enhanced NRE by 17% and 35% and final N recovery system (plant plus soil) by 16% and 24% all relative to N-OATS and N-PLANT groups, respectively. Overall, N-OATS resulted in the largest N derived from fertilizer (NDFF) amount in the deeper soil layer, in overall a delta of 10 kg N ha(-1) relative to the rest of the groups. Notwithstanding corn yield was not affected, early N fertilization under subtropical conditions is not a viable option since NRE was diminished and the non-recovery N increased relative to the in-season N applications. (AU)

• FAPESP's process: 12/24226-5 - DYNAMICS OF NITROGEN IN SOIL-PLANT ENVIRONMENT IN FERTILIZATION SYSTEMS
• Grantee: Silas Maciel de Oliveira
• Support Opportunities: Scholarships in Brazil - Master