Atividade e diversidade da biomassa microbiana em diferentes sistemas de manejo do solo e de culturas no norte do Estado do Parana / Activity and diversity of microbial biomass under different soil and crop management systems in the north of the state of Parana (Brazil)

AUTOR(ES)
DATA DE PUBLICAÇÃO

2005

RESUMO

The microbial biomass carbon (MB-C) and nitrogen (MB-N), basal respiration and metabolic quotient (qCO2) were evaluated in a Rhodic Eutrudox of the North Region of the State of Paraná under different soil and crop management systems. The experimental area was established in 1988/1989 at the experimental station of Embrapa Soja, Londrina, Paraná, and consisted of 7.5m X 30.0m plots under different soil and crop managements; the experimental design was in completely randomized blocks with four replicates. Soil samplings of the 0-10 cm superficial layer, between plant lines were always realized in the morning, from plots under three soil managements, no-tillage (NT), field cultivator (C) and conventional tillage (CT) each with either a crop rotation (R) (lupin - Lupinus albus/maize - Zea mays/black oat - Avena strigosa/soybean - Glycine max/wheat - Triticum aestivum/soybean/wheat/soybean) or crop sequence (S - soybean/wheat); therefore samples were taken from six treatments: NT (R and S), C (R and S) and CT (R and S). Soil samples were analyzed for microbial biomass using two methods, fumigation-incubation and fumigation-extraction and the data were submitted to the analysis of variance and the Tukey test (p<0.05). In relation to the MBC and MBN evaluated by the fumigationextraction method, the higher values were obtained with the NT followed by the management with the field cultivator and the CT; similar results were obtained with the fumigation-incubation method. In relation to the basal respiration, the values obtained followed the order NT >CT >M. The qCO2 with and without sugar induction were higher under CT, followed by the NT and the M managements. The lower qCO2 under NT indicates higher efficiency of the soil microbes, as well as lower losses of soil carbon resulting in higher accumulation of carbon in the soil organic matter with time. No statistical differences were observed related to the different crop systems

ASSUNTO(S)

microbial biomass fumigation-incubation biologia do solo plantio direto solos - manejo fumigation-extraction no tillage system conventional tillage system fumigação extração (quimica)

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