Soil Solution Chemistry in Different Land-Use Systems in the Northeast Brazilian Amazon

Abstract

For sustainable production systems, the nonuse of fire (where there is a greater loss of soil nutrients), would be a solution for the conservation of nutrients in the soil, with the use of management by cutting and grinding, introduction of AFSs (agroforestry systems), and maintenance of riparian vegetation. The concentrations of carbon and nutrients were evaluated in the soil solution in two small hydrographic basins in the municipality of Igarapé-Açu (Pará state) in the eastern Amazon region, Brazil. The evaluations were performed considering the biogeochemical cycling in six land-use classes—riparian forest, secondary forest (capoeira), pasture, slash-and-burn agriculture, chop-and-mulch agriculture, and an agroforestry system (AFS). The objective was to determine the effects of different land-use systems on the composition of the soil solution, aiming to recommend sustainable practices. The concentrations of nutrients were greater in the areas of slash-and-burn agriculture and pasture, indicating greater losses of these nutrients due to runoff and leaching. The loss of nitrate was highest in the slash-and-burn area, while the organic carbon and organic nitrogen losses were greatest in the riparian forest, then in the secondary forest and agroforestry areas.

Agroecossistemas e soberania alimentar na Vila Céu do Mapiá e entorno, Floresta Nacional do Purus

“…A brocagem é a denominação da atividade de limpeza inicial da vegetação mais fina A prática de queima na agricultura é um tema controverso, mas com grande adaptabilidade para os pequenos agricultores amazônicas e é a principal forma de preparar áreas para roçados na FLONA do Purus. Quando essa prática é realizada de forma recorrente na mesma área, acarreta em perdas de elementos, como carbono, nitrogênio, enxofre ao longo dos anos (FELIZZOLA et al, 2022;HÖLSCHER et al, 1997). Por outro lado, alguns estudos apontam que as áreas queimadas podem apresentar maiores teores de pH, cálcio e fósforo nas cinzas, o que é de interesse para os agricultores a curto prazo (FERREIRA et al, 2021a;FREITAS et al, 2013), muitas vezes esses benefícios curtos, aumentando a acidez do solo para o próximo plantio (NETO et al, 2019).…”