Diazotrophic Bacterial Community of Degraded Pastures

Abstract

Pasture degradation can cause changes in diazotrophic bacterial communities. Thus, this study aimed to evaluate the culturable and total diazotrophic bacterial community, associated with regions of the rhizosphere and roots of Brachiaria decumbens Stapf. pastures in different stages of degradation. Samples of roots and rhizospheric soil were collected from slightly, partially, and highly degraded pastures. McCrady's table was used to obtain the Most Probable Number (MPN) of bacteria per gram of sample, in order to determine population density and calculate the Shannon-Weaver diversity index. The diversity of total diazotrophic bacterial community was determined by the technique of Denaturing Gradient Gel Electrophoresis (DGGE) of the nif H gene, while the diversity of the culturable diazotrophic bacteria was determined by the Polymerase Chain Reaction (BOX-PCR) technique. The increase in the degradation stage of the B. decumbens Stapf. pasture did not reduce the population density of the cultivated diazotrophic bacterial community, suggesting that the degradation at any degree of severity was highly harmful to the bacteria. The structure of the total diazotrophic bacterial community associated with B. decumbens Stapf. was altered by the pasture degradation stage, suggesting a high adaptive capacity of the bacteria to altered environments.

The Abundance of N-Transforming Bacteria in Ungrazing and Grazing Area Under Oil Palm- Cattle Integration Management in South Kalimantan

“…It was more likely that the diazotrophic community in this study is altered by soil characteristic, diversity of above-ground vegetation, phenological stage, agronomic activity, and by the niche of colonization than by the activity of cattle on the tree and ecosystem during grazing. Those variables are factors that influenced the diazotrophic community in degraded pastures in Brazil as reported by Oliveira et al [28].…”

Indicadores De Sustentabilidade Com Base Na Qualidade Do Solo E Acúmulo De Fitomassa Em Pastagens Degradadas

“…A reabilitação de pastagens através de tecnologias da bioengenharia para controlar os processos erosivos, em conjunto com práticas de manejo como o pastejo rotacionado, podem interromper ou pelo menos diminuir consideravelmente a degradação das pastagens (SATTLER et al, 2018). Essa afirmação corrobora com Oliveira et al (2017) ao destacarem que as novas tecnologias de produção agropecuária são de extrema importância para o desenvolvimento de sistemas mais sustentáveis, uma vez que, reduzem os impactos negativos nas propriedades do solo e na microbiota benéfica associada as plantas.…”

Differential niche occupation and the biotechnological potential of Methylobacterium species associated with sugarcane plants

“…The test included a positive control, the bacterial strain EN303, and Pseudomonas oryzihabitans (Kuklinsky et al, 2004). This test is still a widely-used approach to perform bacteria screening for in vitro physiological potential, as assumed by many authors in recent works (Quecine et al, 2012;Oliveira et al, 2017;Batista et al, 2018;Leite et al, 2018;Rodriguez et al, 2018).…”

“…In order to overcome this problem, some researchers have suggested the use of microorganisms associated with plant as a sustainable alternative that could reduce the environmental impact on the ecosystem caused by agrochemicals and then improve plant growth promotion (Ambrosini et al, 2015;Majumder et al, 2016;Oliveira et al, 2017;Leite et al, 2018).…”