Contribution of a mixed inoculant containing strains of Burkholderia spp. and Herbaspirillum ssp. to the growth of three sorghum genotypes under increased nitrogen fertilization levels

The 15N natural abundance technique to assess the potential of biological nitrogen fixation (BNF) in some important C4 grasses

“…The proportions found are within ranges reported by Miranda et al (1990), for different guinea grass genotypes, and Montañez et al (2009), for maize genotypes. Sorghum performance was lower than that reported by Ferreira Neto et al (2017) and Santos et al (2017) in the field, the only latest report of BNF in sorghum. Nevertheless, sorghum cultivar IPA-1011 was able to benefit from a higher proportion of atmospheric N 2 than sugarcane variety RB863129.…”

“…For example, results have shown that some varieties cultivated in Brazil Baptista et al, 2014) and Uruguai (Taulé et al, 2012) may obtain significant amounts of atmospheric N, but no evidence of BNF was found in sugarcane grown in other places, such as Australia (Biggs et al, 2002) and South Africa (Hoefsloot et al, 2005). For other grasses such as sorghum (Santos et al, 2017;Ferreira Neto et al, 2017), Guinea grass (Miranda et al, 1990), maize (Montañez et al, 2009) and elephant grass , reports are scarce.…”

Nitrogen fixation of Poaceae and Leguminoseae in a green manure experiment in the Brazilian semiarid region

“…Inoculation with previously selected, high fixing, compatible bacteria species could correct the problem (Marinho et al, 2014) but this is not a common practice in the country or in other areas, where jack beans is planted as a green manure species (Ojien et al, 2007). Confirming that fixation can occur in Poaceae species (Miranda et al, 1990;Montañez et al, 2009;Morais et al, 2012;Urquiaga et al, 2012;Santos et al, 2017), maize and sorghum had low δ15N signal and in the case of sorghum even lower than the signals of all legume species. Proportions of Poaceae plant N derived from fixation vary much depending on the species and environmental conditions and are usually inferior to those of legume species (Alves et al, 2015;Santos et al, 2017).…”

“…Confirming that fixation can occur in Poaceae species (Miranda et al, 1990;Montañez et al, 2009;Morais et al, 2012;Urquiaga et al, 2012;Santos et al, 2017), maize and sorghum had low δ15N signal and in the case of sorghum even lower than the signals of all legume species. Proportions of Poaceae plant N derived from fixation vary much depending on the species and environmental conditions and are usually inferior to those of legume species (Alves et al, 2015;Santos et al, 2017). The lower δ 15 N signal of sorghum is an important issue because it rules out the possibility that the atmospheric N present in these sorghum plants was transferred by the legume species (Peoples et al, 2015).…”

“…Planting these Poaceae species as sole green manure crops is not a common practice but they have been lately tested as part of mixtures of several species planted together (Snapp et al, 2005;Miyazawa et al, 2010;Pimentel et al, 2011;Feitosa et al, 2015;Mouco et al, 2015;Pereira Filho et al, 2016). These mixtures have the potential to maximize biomass production but little is known of their capacity to fix N. Perhaps the lack of information comes from the variability of fixation in the Poaceae, apparently high in some places (Montañez et al, 2009;Morais et al, 2012;Taulé et al, 2012;Baptista et al, 2014;Santos et al, 2017) but completely absent in other places (Biggs et al, 2002;Hoefsloot et al, 2005). If fixation of these Poaceae as sole crops is little known, even less has been studied when several species are mixed, including legume species in the mixture.…”