Produção e teor de nutrientes da liteira fina de capoeiras em terra preta de índio e solos adjacentes

Abstract

The Amazonian Dark Earths (ADE) are stains of soils found in the so hole Amazon basin, mainly at the margins of the large rivers. They were likely originated the deposition for long periods of organic residues produced by the activities of pre- Columbian populations, living in old indigenous groupings, and production such anthropic soils, locally called Terra Preta de Índio . These soils are rich in nutrients (P, Ca, Mg and micronutrients) and, due to their fertility, are of great local importance, for small-holders agricultural production. Together with ADE generally occurs the Terra Mulata (TM), a transition between ADE and the adjacent soils of mineral origin, usually classified as Yellow Latosols (LA) (Oxisols). To study the dynamics of the fine litter in second growth (capoeiras) in 20 year-old on anthropogenic soils repeated plots in ADE, TM and LA measuring of 20 x 80 m were installed at four different locations: Manaus, Iranduba Rio Preto da Eva and Rio Urubu (All in Central Amazon). Fine litter fall was sampled every two weeks during the year of 2005, and the litter layer on soil surface at 3 month intervals. In the dry season a soil sampling (0-30 cm) was made for characterizing chemically the soil upper layers. Fine litter was sorted into components oven-dried at 65º during 72 hours, weighed and grinded. Soil and litter were analyzed at Thematic Laboratory for Soils and Plants, at INPA, where they determined macro and micronutrients. The results confirmed larger concentrations of nutrients in the anthropogenic soils when compared to LA, mainly for P, Ca, Mg, Cu, Mn and Zn. Exchangeable Al, H+ Al and Fe largest concentrations were found in the adjacent LA. The largest fine litter productions were found for the capoeiras in ADE and TM, except for the site located in Manaus. All capoeiras presented larger fine litter production during the dry season. The largest coefficient of decomposition for the litter layer (kL) was shown at the plots in ADE and TM. There were positive relationships among nutrients in the soil and nutrients in the fine litter for the upper soil layer (0-10 cm) mainly at the anthropogenic soils.