Composição química de solos modificados a partir de resíduos de serrarias no município de Tailândia- Pa.

Abstract

The Amazonian timber sector has experienced significant development in recent decades, especially in regions such as Tailândia, considered one of the largest timber production centers in the state of Pará. However, much of the wood used is wasted, being incinerated or accumulated in inadequate sites. The objective of this study was to determine the chemical composition of soils in sawmill residue deposits in samples of different ages. A survey of the sawmills in activity and/or deactivated in the municipality and the collection of sawdust samples (RA), soil samples with waste (AS+AR) and soil samples (AS) on which the waste piles accumulate were carried out. pH, Ca, Mg, Na, K, AI, P, C, Fe, Zn, Cu, Mn were determined by the methods proposed by EMBRAPA (1997) and FCAP (1991). The results obtained for the average pH values were 5.18 , 6.12 and 5.56 in AR, AS+AR and AS, respectively. The average Ca and Mg contents were 10.45 and 2.61 cmolc .kg-1 in RA; 8.28 and 1.61 cmolc .kg- 1in RA+SA and 3.33 and 0.78 cmolc .kg-1in SA, respectively. For the elements Na and K we obtained 3.92 and 0.37 cmolc .kg-1 in RA, 1.19 and 0.88 cmolc .kg' 1 in RA+AS and 0.32 and 0.14 cmolc .kg-1 in AS, respectively. IA showed 2.52 cmolc .kg' 1inAR; 1.64 crnolkq" inAR+AS and 1.50 cmolc .kg-1 in AS. The P contents were 2.02 g.kg- 1 in RA, 18.57 g.kg' 1 in RA+AS and 21.03 g.kg'1 in AS, while those of C in RA+AS and AS averaged 42.22 and 10.77 g.kg'1 of soil, respectively. For micronutrients the following average contents were obtained: Mn - 283,17,125,39 and 60,12 rnq.kq'; Zn 144,68, 46,37 and 35,21 mq.kq"; Cu - 82,69,27,66 and 12,74 mg.kg-1 and Fe 9118, 11672 and 7878 mg.kg'1 in the samples of RA, RA+AS and AS, respectively. The elements C, Ca, Mg, Na, Zn, Mn and Cu showed significantly higher values in the sawmill waste compared to the soils. This may indicate that the residues of plant origin had great importance for the genesis of anthropogenic soils such as the Archeological Black Earths, which are soils rich in these elements. While the source of P, an element that presents high values in the TPA's, seems to be linked to the animal waste, since the results indicated significantly higher values in the soils when compared to the samples of waste analyzed.