Inoculation of sugarcane with diazotrophic bacteria

Abstract

SUMMARYThe sugarcane industry, a strategic crop in Brazil, requires technological improvements in production efficiency to increase the crop energy balance. Among the various currently studied alternatives, inoculation with diazotrophic bacteria proved to be a technology with great potential. In this context, the efficiency of a mixture of bacterial inoculant was evaluated with regard to the agronomic performance and N nutrition of sugarcane. The experiment was carried out on an experimental field of Embrapa Agrobiologia, in Seropédica, Rio de Janeiro, using a randomized block, 2 × 3 factorial design (two varieties and three treatments) with four replications, totaling 24 plots. The varieties RB867515 and RB72454 were tested in treatments consisting of: inoculation with diazotrophic bacteria, N-fertilized control with 120 kg ha -1 N and absolute control (no inoculation and no N fertilizer). The inoculum was composed of five strains of five diazotrophic species. The yield, dry matter accumulation, total N in the shoot dry matter and the contribution of N by biological fixation were evaluated, using the natural 15 N abundance in non-inoculated sugarcane as reference. The bacterial inoculant increased the stalk yield of variety RB72454 similarly to fertilization with 120 kg ha -1 N in the harvests of plant-cane and first ratoon crops, however the contribution of biological N fixation was unchanged by(1) Part of the doctoral thesis of the first author, Post-graduation course in Agronomy -Soil Science (CPGA-CS) at the Rural Federal University of Rio de Janeiro -UFRRJ. Received for publication on January 16, 2013 and approved on January 6, 2014. (2) Post-graduate student at CPGA-CS, Soil Science Department, UFRRJ. BR 465, km 7. CEP 23890-000 Seropédica (RJ), Brazil. O aumento da eficiência produtiva da cana-de-açúcar com tecnologias que possibilitem aumentar seu balanço energético é uma necessidade do setor sucroenergético, por se tratar de uma cultura estratégica para o país. Entre as diversas alternativas atualmente estudadas, o inoculante com bactérias diazotróficas vem se evidenciando uma tecnologia com elevado potencial. Diante desse contexto, este estudo teve como objetivo avaliar a eficiência do inoculante bacteriano no desempenho agronômico e na nutrição nitrogenada da cana-de-açúcar. O ensaio foi realizado no campo experimental da Embrapa Agrobiologia, em Seropédica, RJ. O delineamento experimental foi em bloco ao acaso, em esquema fatorial 2 × 3 (duas variedades e três tratamentos), com quatro repetições, totalizando 24 parcelas. As variedades utilizadas foram a RB867515 e RB72454. Os tratamentos foram: inoculação com bactérias diazotróficas, controle nitrogenado com 120 kg ha -1 de N e controle absoluto (sem inoculação e sem N). O inoculante foi composto por cinco estirpes de cinco espécies de bactérias diazotróficas. As variáveis avaliadas foram a produtividade de colmos, o acúmulo de matéria seca e N total da parte aérea das plantas e a contribuição da fixação biológica de N (FBN), utilizando como referên...

The biostimulant manufactured using diazotrophic endophytic bacteria and humates is effective to increase sugarcane yield

“…Among the way and time application tested, we demonstrated that the best biostimulant delivering method was one single foliar spray at 60 dap per crop cycle (Table 4). The first attempt to use plant growth-promoting bacteria in sugarcane crop field in Brazil was made by Embrapa Agrobiologia, which recommended the immersion of stalks for 30-60 min inside containers filled with inoculant suspension before planting [18]. They observed an average increase of 13% (equivalent to 24 tons ha −1 ) on crop yield without changes in 15 N balance, indicating that the plant growth-promoting benefits may have resulted from a better nutrient use efficiency than significant nitrogen input by biological nitrogen fixation in the soil-plant system.…”

Isolation and selection of plant growth-promoting bacteria associated with sugarcane

“…Isolation, in vitro characterization of growth promotion factors, inoculation and plant response to bacteria associated with sugarcane have already been described (Mirza et al 2001, Silva et al 2012, Beneduzi et al 2013, Schultz et al 2014. However, little is known about the inoculation of PGPM isolated from sugarcane in other plant species.…”

Diazotrophic bacteria associated to sugarcane varieties cropped at Northeast Region of Brazil

“…This variety was used during other surveys of diazotrophic bacteria counts and isolates identification in Brazil (Magnani et al, 2013) and for inoculation studies using five different diazotrophs known to contribute for plant growth promotion Schultz et al, 2014). It is known to be adapted to soils of low fertility throughout the Brazilian territory.…”

“…Several studies report that diazotrophic bacteria promote a significant development in sugarcane (Oliveira et al, 2006;Schultz et al, 2012;Schultz et al, 2014). Urquiaga et al (2012) estimated the contribution of biological nitrogen fixation (BNF) in nine varieties using two different methods and found that at least 40 kg N ha -1 per year derived from this biological process, although the contribution rate differed according to the tested genotype.…”