RESUMO
Aims@#Aerobic rice is a potential crop introduced to encourage water conservation in rice planting. However, a decline of aerobic rice yield has been reported and thus this study was initiated with the aim to observe the response of microbial community in this environment which are exposed to various plant growth stage and soil types. @*Methodology and results@#To determine the effect of soil types such as peat and sandy clay loam on microbial community. A total of four growth stages were tested namely vegetative, reproductive, ripening and maturing. To determine the influence of growth stages and soil types towards microbial community in aerobic rice, Biolog Ecoplate™ technique was used to quantify the response of microbial community through microbial functional diversity and carbon source utilization. The abundance of culturable aerobic bacteria, fungi, actinomycetes, nitrogen-fixing microorganism and phosphate-solubilizing microorganism were determined using five different selective media. Soil physical and chemical properties as well as total nitrogen in plant tissues were also determined. It was found that microbial functional diversity during plant growth (except for microbial evenness) varied between the soil types. Correlation analysis revealed different relationships between carbon source utilization and microbial functional diversity in both soil types. @*Conclusion, significance and impact of study@#Microbial community in rhizosphere responded according to plant development which is primarily determined by soil type. Therefore, it is concluded that soil type particularly the soil physical and chemical properties are important factors in shaping the microbial community by directly influencing the rhizosphere environment.
RESUMO
O crescimento da agricultura e pecuária, que pode resultar em abertura de novas áreas de plantio, tem motivado pesquisas que buscam sistemas de produção mais sustentáveis, cujo manejo causa menor impacto e degradação do solo. O manejo do solo e a cobertura vegetal alteram suas propriedades, principalmente, as microbiológicas, provocando mudanças na densidade de microrganismos funcionais. O objetivo deste trabalho foi avaliar o efeito dos sistemas de manejo e dos diferentes sistemas de plantio, sobre a densidade de grupos funcionais de microrganismos em solos de Cerrado. As coletas de solo foram feitas em duas profundidades (0-5 cm e 5-20 cm) e dois períodos (seco e chuvoso), nos seguintes tratamentos: plantio direto (PD), plantio direto com rotação (PDR), plantio convencional (PC), plantio convencional com rotação (PCR) e Cerrado nativo (Mata mesofítica). A vegetação nativa apresentou as maiores densidades microbianas, nos períodos seco e chuvoso, em ambas as profundidades analisadas. Em geral, os tratamentos PDR e PD apresentaram maiores densidades microbianas nas camadas mais superficiais. Os dados de correlação linear (r) entre os grupos totais e funcionais de microrganismos e os atributos químicos do solo variaram entre os sistemas de preparo do solo. A correlação entre grupos funcionais de microrganismos e os atributos químicos do solo foram variáveis nos diferentes sistemas de manejo. Concluiu-se que o solo de cerrado apresentou maior densidade microbiana, não houve diferença na densidade microbiana entre os sistemas de preparo no período seco.
Growth of agriculture and livestock can result in opening new areas for planting and has increased research to obtain sustainable production systems with lower impact and soil degradation. Soil management and cover plant alters their properties, mainly, microbiological one, leading changes on functional microorganisms density. The aim of this word was to evaluate the effect of management systems and different planting systems on density of functional groups of microorganisms in cerrado soil. Soil samples were collected in two layers (0-5cm e 5-20cm) and two periods (dry and wet season). The treatments studied were: no-tillage (NT); no-tillage with crop rotation (NTCR); conventional tillage (CT); conventional tillage with crop rotation CTCR) and native Cerrado (mesophytic forest). Native Cerrado showed higher microbial density at both layers and periods of evaluation. In general, the treatments NTCR and NT had the highest microbial density at superficial layers. The results of linear correlation between functional groups of microorganisms and chemical soil varied among tillage system. It was concluded that cerrado soil presented higher microbial density and microbial density was similar among soil management at dry period.