Dynamic of organic matter and microbial biomass in a soil under different management systems in the Western Amazon

• Autor(a) principal: Moreira, Adônis
• Data de Publicação: 2004
• Outros Autores: Malavolta, Eurípedes
• Tipo de documento: Artigo
• Idioma: por
• Título da fonte: Pesquisa Agropecuária Brasileira (Online)
• Texto Completo: https://seer.sct.embrapa.br/index.php/pab/article/view/6883
• topic: Theobroma grandiflorum; forest; nitrogen; carbon; basal respiration; metabolic quotient; Theobroma grandiflorum; floresta primária; carbono; nitrogênio; respiração basal; quociente metabólico

The objective of this work was to evaluate the alterations of the microbial biomass activity as an indicator of C and N dynamics in a soil submitted to the succession of plant cover and management in the Western Amazon. The work was carried out in two chronosequences: CA – a succession from primary forest to a three years old cupuaçu (Theobroma grandiflorum) plot – and CB – a succession from primary forest to an eight years old Brachiaria humidicola pasture and a three years old cupuaçu plot. The succession primary forest-pasture-cupuaçu affects negatively the stock of the soil carbon, with significant decrease of organic matter and C of the soil microbial biomass. The primary forest presents lower metabolic quotient and higher C/N ratio of the biomass, which results in less carbon loss. The N of the microbial biomass found in the 0–10 cm layerir respective of the management adopted, increases significantly in the cupuaçu plot and the total N decreases. Ammonium concentration decreases according to soil depth, but this does not occur with nitrate.