Caracterização de solos e modificações provocadas pelo uso agrícola no assentamento Favo de Mel, na região do Purus Acre

• Ano de defesa: 2000
• Autor(a) principal: Araújo, édson Alves de
• Orientador(a): Lani, João Luiz
• Banca de defesa: Ker, João Carlos , Costa, Liovando Marciano da , Ribeiro, Guido Assunção , Alvarenga, Ramon Costa
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de Viçosa
• Programa de Pós-Graduação: Mestrado em Solos e Nutrição de Plantas
• Departamento: Fertilidade do solo e nutrição de plantas; Gênese, Morfologia e Classificação, Mineralogia, Química,
• País: BR
• Palavras-chave em Português: Uso da terra; Solos; Acre; Assentamentos rurais; Degradação do solo
• Palavras-chave em Inglês: Land use; Soils; Acre; Human settlements; Soil degradation
• Área do conhecimento CNPq: CNPQ::CIENCIAS AGRARIAS::AGRONOMIA::CIENCIA DO SOLO::MANEJO E CONSERVACAO DO SOLO
• Link de acesso: http://locus.ufv.br/handle/123456789/5549

Actually in Acre the extensive pastures and the settlement projects (PA s) are responsible for most deforestation. The itinerant agriculture where the soil is used over a 2-year period prevails in PA s. Later on, the soil is left on fallow for recovering its fertility and/or to be incorporated to the extensive pasture. The use of the soil for a longer period and under a sustained way could be reached if appropriate management practices are adopted, so avoiding the deterioration of the soil as to its physical, chemistry and biological characteristics. From this premise it was objectified to characterize the soils and evaluate their physical and chemical alterations under different use types and so to supply subsidies to decision making on a more rational use. So, four locations inserted in the same soil conditions were selected (distrophic Yellow Argisols medium/clayish texture plane relief) at the Favo de Mel settlement on eastern Acre, in Purus region. The evaluated uses were: natural forest (control); natural newly-opened up forest submitted to intensive burning; planting of 2-years old pupunha (Bactris gassipae) and 4-years old brachiaria pasture (Brachiaria brizantha). Also, informal interviews were performed with farmers, and the root system were evaluated through digital images. It was concluded that the soil under pasture presented the highest density values, so suggesting a tendency to compaction. The nutrients and the organic carbon are found at low contents as well as concentrated in the first soil centimeters; and they tended to increase with intensity and time of soil use. The potassium drastically decreased in the pasture ecosystem, possibly due to losses by erosion and removal by pasture. The humina fraction prevailed on all four systems of soil use. Most vegetal biomass of the forest roots were concentrated down to 20-cm soil depth. There was also high correlation between the area and length of the roots. The farmers of Favo de Mel are coming from unsuccessful settlements, and the desistance index has been relatively low, so corroborating the importance of the environment on man's permanence in field.