Contribuição de estudo econômico na utilização de resíduos de serraria para a formação de Terra Preta Nova (TPN)

Abstract

The municipality of Tailândia located in the northeast of the State of Pará is considered one of the major logging centers, responsible for approximately 8% (850,000m3) of the State's production. The town has 48 sawmills, generating a large accumulation of waste that is not used, deposited in the open and generally incinerated. For this reason the municipality was chosen for the development of the Terra Preta Nova (TPN) project. In general terms, this project aims to recreate anthropic soils known as Terra Preta Arqueológica (TPA), using butcher's waste, various vegetal components, among them sawmill waste. Blade residues are also being used, since 1999, as mulch in pupunha (Bactris sp) and paricá (Schízolobium amazonícum) plantations, by the wood lamination company (Tailâminas Ltda). This work aims to evaluate the economic feasibility of using sawmill waste as a cover for plantations, providing support for research on NTBT. The search for qualitative and quantitative data was carried out through the application of questionnaires in 22 sawmills belonging to the union (SlNDIMATA) of this sector. In addition, with the company Tailâminas, costs/benefits of plantations of paricá and pupunha with coverage were evaluated. The calculation of the production cost was based on the operational cost structure (COT). The calculation of the benefit is being evaluated through the growth/development of trees (diameter at breast height - DBH) of paricá, in comparison with these measurements in areas without coverage, in an area of 1 ha each. The 22 logging companies studied use an average of 850 m3 of wood per month. Of this production up to 500m3 are discarded, since to produce 1m3 of sawn wood 2 to 3 m3 of roundwood are needed. From the amount of local lumber companies, only one tries to put the residues to some use and the great majority consider them to be a big problem that must be solved. Regarding the benefit, it can be observed that in the paricá plantation with cover, it presented trees with relatively higher DBH than the trees on the ground without cover. From the data obtained so far, it can be considered that the use of wood residues as a ground cover for planting perennial crops is bringing good results, proven through the DBH. Certainly the use of sawmill residues for the formation of TPN will bring great benefits for the improvement of the soil, besides the use of these residues that currently is an environmental problem.