Corn Yield and Foliar Diagnosis Affected by Nitrogen Fertilization and Inoculation with Azospirillum brasilense

Abstract

ABSTRACT:The biological nitrogen fixation (BNF) process in grasses is caused by diazotrophic bacteria, particularly Azospirillum brasilense. However, studies are lacking on BNF efficiency to define how much mineral nitrogen (N) can be applied to achieve more sustainable high yields. Furthermore, there should be an analysis of whether urea with the urease enzyme inhibitor NBPT is less harmful, benefiting BNF in grasses. The objective of this study was to evaluate the effect of N sources and N rates associated with inoculation with Azospirillum brasilense regarding foliar diagnosis and leaf chlorophyll index (LCI), agronomic efficiency (AE), and corn grain yield in the Cerrado (Brazilian tropical savanna) region. The experiment was conducted in a no-tillage system in a Latossolo Vermelho Distroférrico (Oxisol). A randomized block experimental design was used with four replications in a 2 × 5 × 2 factorial arrangement as follows: two N sources -urea and Super N, urea with urease enzyme inhibitor NBPT [N -(n-butyl thiophosphoric triamide)]; five N rates (0, 50, 100, 150, and 200 kg ha -1 ) applied in topdressing; and two seed inoculation treatments, one with and one without A. brasilense. N rate positively influenced the LCI and concentrations of N, S, and Mn in leaves, and may increase the concentrations of P, Cu, and Fe; however, higher N rates can reduce AE. The N sources had similar effects, and therefore urea is recommended for N fertilization. Inoculation with A. brasilense decreased leaf concentration of Fe and increased LCI, leaf concentration of P, AE, and corn grain yield; the use of this diazotrophic bacterium is therefore viable even when high rates of N are applied.

Technical and Economic Viability of Corn with Azospirillum brasilense Associated with Acidity Correctives and Nitrogen

“…In several studies, increases in corn grain yield are reported with the application of N doses in the cover (Kappes et al, 2013;Kappes et al, 2014;Galindo et al, 2016), einforcing the results obtained. Meira et al (2009) observed that NH 3 volatilization losses among the various fertilizers, including urea, did not reflect corn yield.…”

“…Similarly, Galindo et al (2016), studying N doses in top-dressing (0, 50, 100, 150 and 200 kg ha Positive results with the use of Azospirillum were also reported by Kappes et al (2013), working with doses of N and inoculation with A. brasilense in corn in the first harvest. According to the authors, inoculation resulted in a 9.4% increase in grain yield.…”

“…In order to obtain high corn grain yield it is necessary to apply high doses of nitrogen (N), because the soils, in general, do not supply the demand of the crop during its cycle (Teixeira Filho et al, 2014;Galindo et al, 2016). Nitrogen fertilization is one of the highest costs of the production process of non-leguminous crops (Nunes et al, 2015).…”

Inoculation with Bradyrhizobium sp. and Azospirillum brasilense Associated with Application of Cobalt and Molybdenum on Nutrition and Soybean Yield

“…Corn plants that were inoculated with A. brasilense had greater LCI than those that were not inoculated, in two crop seasons [31]. Kappes et al [32] and Quadros et al [33] found that plants inoculated with A. brasilense had improved LCI.…”

Modes of application of cobalt, molybdenum and Azospirillum brasilense on soybean yield and profitability

“…Considering the main current and potential limitations of BNF in the soybean crop and the benefits attributed to the various crops by the inoculation with Azospirillum (free-living diazotrophic bacteria), especially the greater development of the root system and, consequently, also higher absorption of water and nutrients (Galindo et al, 2016), it is deduced that, with the co-inoculation in microorganism, there may be improvements in the performance of the crops in an approach that respects the current demands for agricultural, economic, social and environmental sustainability (Hungria et al, 2013).…”