Avaliação da Biomassa Microbiana e Nutriente do Solo na Melhoria Tecnológica do Uso da Terra em Igarapé-Açu-PA (Rede Tipitamba)

Abstract

In the Amazon, agricultural exploration occurs at the cost of environmental degradation, motivating researchers to search for alternatives to the traditional system. In this search, an experiment was set up to evaluate the microbial biomass (MBM) and soil nutrients in 3 areas: 4A (4 years of fallow), 4B (2 years of fallow), 4C (production area, after 3 years of fallow). All experimental areas are from the Tipitamba Project, which aims to evaluate soil management with slash and burn technology for the sustainability of annual, semi-permanent and permanent crops in the context of family farming, with emphasis on alternatives to the use of fire in the Amazon. Each experiment was submitted to the following types of soil preparation: slash and burn (Q), slash and burn with mulch (C), and slash and burn with incorporation of ground material (I) and two levels of fertilization, with and without NPK. Samples were collected from 0-10 cm of soil in 2006 and evaluated using the fumigation-extraction method and compared with non-fumigated samples and the following characteristics were analyzed: Organic carbon (TOC), microbial biomass carbon (MBOC), total nitrogen (NT) and nitrogen of microbial biomass (N-BMS); besides the ratio C-BMS/COT and N-BMS/NT. The experiment that showed the best results for TOC (18.52 g kq'), C-BMS (1.17 g kg1), C-BMS/COT (18.06 %) and NT (4.56 9 kq') was experiment 4A, indicating a better balance in this system. Experiment 4C showed the highest values of N-BMS (0.45 g kq') and N-BMS/NT ratio (48.46 %), probably because of the greater diversification of plant material in the soil. The treatments C+ NPK and I-NPK showed better results, respectively, for C-BMS and N-BMS, proving to be better soil management alternatives