Sustainable nitrogen efficiency in wheat by the dose and mode of supply¹

Eficiência sustentável do nitrogênio em trigo pela dose e forma de fornecimento

HIGHLIGHTS:

Unfavorable years of wheat cultivation promote greater nitrogen losses.

Topdressing nitrogen fractionation does not increase productivity.

The technical efficiency of nitrogen is not suitable for cultivation recommendation.

ABSTRACT

The management of nitrogen by the assessment of agronomic and environmental indicators ensures satisfactory productivity with higher environmental quality. The objective of this study was to propose more sustainable management of nitrogen use in wheat, considering the supply of full and fractioned doses with an estimate of technical, economic efficiency, and expected productivity. Two experiments were conducted, one to quantify biomass productivity and the other to evaluate grain yield. The experimental design consisted of a randomized block with four repetitions in a 5 × 3 factorial, for N-fertilizer doses (0, 30, 60, 90, and 120 kg ha^-1) and nutrient supply form [full condition (100%) in the phenological stage V3 (the third leaf expanded); fractionated (70/30%) in the phenological stage V₃/V₆ (third and sixth leaf expanded) and; fractionated (70/30%) in the phenological stage V₃/R₁ (beginning of anthesis)], respectively. The most sustainable management of nitrogen in wheat was obtained with the expected yield rate of 3 t ha^-1 by manual fertilization, with nitrogen supplied in full dose at the V₃ phenological stage.

Key words:
Triticum aestivum L.; full dose; fractionated dose; satisfactory productivity