Micronutrient Accumulation with Azospirillum Brasilense Associated with Nitrogen Fertilization Management in Wheat

ABSTRACT

Alternative options to feed an ever-growing global population requires to be developed to supplement chemical fertilizer use. Nitrogen (N) is the chemical fertilizer most used for non-legume crops. Research showing the potential for management practices which supplement the use of N fertilizer is utmost important. This research was developed to investigate the potential use of Azospirillum brasilense to enhance micronutrient accumulation in wheat cropping systems; and, to assess the potential interactions between biological nitrogen fixation (BNF) and urease inhibitor N-(n-butyl) thiophosphoric triamide (NBPT). The objective was to evaluate the effect of N sources and doses associated with inoculation with A. brasilense, regarding micronutrients accumulation, and its influence on wheat grain yield in Savannah conditions. The study was carried out in a Rhodic Hapludox under no-tillage. The experimental design was a randomized complete block design with four replications arranged in a 2 × 5 x 2 factorial scheme: two N sources (urea and urea with NBPT), five N rates (0, 50, 100, 150 and 200 kg ha⁻¹), with and without A. brasilense inoculation. N rates increased the uptake and removal of micronutrients. Urea with NBPT was not efficient in optimizing nitrogen fertilization. Inoculation with A. brasilense provided a higher accumulation of Cu, Fe, Mn and Zn in the straw and Mn and Zn in grains. The inoculation with A. brasilense associated with 140 kg ha⁻¹ of N provided increased wheat grain yield.

KEYWORDS:

• Triticum aestivum L.
• nitrogen sources
• biological nitrogen fixation
• urease inhibitor
• nutrients removal