Micronutrientes (fe, mn, cu e zn) no solo com cobertura de resíduos de madeira em culturas de paricá (schizolobium amazonicum), Tailândia-Pa

Abstract

According to BRAND & MUNIZ (2000), the yield of the veneer industry is low, reaching 40.7%, indicating that more than half the wood entering the process becomes waste, which can generate serious socio-environmental problems if disposed of incorrectly. For the last 6 years (2004), the veneer manufacturer Tailâminas Plac, located in the municipality of Tailândia - northeast region of Pará - has been using veneer residues as organic material for soil covering in Paricá (Schízolobíum amazonícum) forest cultures. This work aimed to verify the Fe, Mn, Cu, and Zn contents present in the soil of Paricá cultures, to monitor the development of the trees, and to make the community aware of the correct final destination of solid residues. Recycling workshops were held for teachers and students from public schools in the municipality, in the belief that Environmental Education brings permanent critical evaluation and solid social formation for environmental conservation DIAS (2000). As for the soils, 90 samples were taken, 45 in the 1 ha area with added residue (CR) and 45 in the area without coverage (SR), evenly distributed (20x20 m). The micronutrients were determined by atomic absorption (EMBRAPA, 1997). The results show that the CR area presented higher mean values of concentration (mg/Kg) of Zn (CR = 29.72 and SR = 22.85), Cu (CR = 29.72 and SR = 22.85) and Fe (CR = 1.7 and SR 1.5 %). The variation of Mn in the CR area was from 67.58 to 142.59 and in the SR from 57.53 to 202.51 mg/Kg. In the area with added residues, the trees presented a greater development, mainly in the central part, having the average DBH value of 20.15 cm, reaching 34 cm. In the SR area the average DBH was 17.54 cm and the largest measurement was 31 cm. MONTEIRO (2004) states that the addition of residues in this culture contributed to the improvement of physical and chemical properties of the soil, with considerable increase in the concentration of Ca and MO and greater diameter of the trees. It was verified, however, through the geochemical distribution maps that the highest concentration of these micronutrients did not coincide with the areas that presented the greatest DBH. Therefore, although the I and Zn present significantly higher values in the area with residues, these micronutrients do not seem to have influenced the growth of the trees