Quantificação de Carbono e Nitrogênio da Biomassa Microbiana e Avaliação do Papel dos Microorganismos na Transformação dos Resíduos Orgânicos, Tailândia, Pará

Abstract

The objective of this work was to quantify the carbon and nitrogen of the soil microbial biomass in the TPN (Terra Preta Nova) replication experiment from the application of organic residues. A TPN replication experiment was set up in the municipality of Tailândia, Pará, using an experimental model composed of 68 plots (3x3 m), with combinations of the following treatments: charcoal (C), sawdust residue (RPS), ground blade residue (RL T), bone, blood and fat residue (RA), as well as a witness plot (without residue application). Soil samples were collected in the dry and rainy periods, 2003 to 2005, respectively, at a depth of 0-5 in, for the microbiological analyses and 0-5 and 5-15 in depth for the analyses of microbial carbon (Cmic) and microbial nitrogen (Nmic) contents. The microbiological analyses (fungal and bacterial quantification) were performed by means of the "Pour Plate" technique, using the culture media Standard Agar (bacteria) and acidified Potato Agar (fungi). The Cmic and Nmic were determined by the Fumigation-Extraction method (Vance et al., 1987). The results obtained showed higher values of Cmic and Nmic in areas where greater diversities of residues were incorporated. There was a significant higher correspondence under C+RLT+RA and RPS+RLT. The highest microbial population quantification was also obtained at these sites. The residue additions to the soil demonstrated the possibility of recovery of Cmic contents and soil biodiversity in the medium term (three years). The C/N ratio was a factor of positive interference in the microbial diversity of the studied soil.