Wheat Nitrogen Fertilization Under no Till on the Low Altitude Brazilian Cerrado

Abstract

This study evaluates the effects of different nitrogen (N) rates (0, 50, 100, 150, and 200 kg ha⁻¹) and sources (ammonium sulfate, urea, and ammonium sulfonitrate with a nitrification inhibitor, Entec®) applied either as a single application during sowing (next to the planting rows) or as side dressing (stage 3.2 on Zadok scale), on production components and grain yield of irrigated wheat grown under no-till in a low-elevation Brazilian cerrado and Dark Red Dystrophic Latosol with clayey-texture. It was adopted a randomized block design (5 × 3 × 2) in factorial scheme with four replications. The N sources provided similar grain yields and chlorophyll contents. Increased nitrogen rates increased grain yield up to the 120 kg N ha⁻¹, regardless of application time and N source. Nitrogen fertilization as side dressing can be recommended based on leaf chlorophyll readings. Early application of all nitrogen fertilizers at sowing time was viable.

Keywords:

• Triticum aestivum L.
• nitrogen rates
• nitrogen sources
• time of nitrogen application
• nitrification inhibitor

FUNDING

The authors gratefully acknowledge the financial support by CAPES, FAPESP (Proc. 2006/04277-3) and CNPq from Brazil.