Bioindicadores de qualidade do solo avaliados em diferentes profundidades sob plantio direto e convencional


IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia




Quantitative and qualitative studies of the microbiota show the changes in an agroecosystem, because of the management systems. Several studies have concluded that no-tillage (NT) is the agricultural management system that best preserves the quality of soil in relation to the PC. However, in most studies related to management system calculations are expressed in terms of soil mass (e.g. mg kg-1 soil), without adjusting the values with the correct soil density. As the managements of PD and PC alter the density, it is possible that there are differences in the metabolic activity and survival of microorganisms with soil depth. Therefore, only by comparing the depths, one could verify the impact caused by the ground systems of PD and PC. The experiment was conducted at Embrapa Soja in Londrina (PR) in Oxysoil (Latossolo Vermelho Eutroférrico) established in the summer of 1988/89. In January 2009 samples were collected between the lines, in seven depths 0-5, 5-10, 10-20, 20-30, 30-40, 40-50 and 50-60 cm under conventional tillage (PC) and no-tillage (NT) plots cultivated under succession soy and wheat. The experimental design consisted of randomized blocks, with four replications. We studied the following variables: physical, chemical atributes, total C and total N, microbia biomass-C (MB-C) and N (MB-N), metabolic quotient (qCO2), microbial quotient (qMIC), basal respiration (BR) and substrate-induced (BRI), enzyme analysis and denaturing gradient gel electrophoresis (DGGE) for analysis of bacterial and fungal. This study confirmed that the NT system favored the CBM for the CT, even if the differences in the density of soil are considered in their determination. The MBC, MBN and metabolic activity of microorganisms accompanying the distribution of SOM in the profile and decrease with soil depth. The qualitative aspects should be better studied, because they have inherent meaning in the explanation of many processes and is the major weakness of this work.


biotecnologia microbiana microbiologia agrícola solos - manejo biomassa microbial biotechnology agricultural microbiology soil management biomass

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