ABSTRACT
Different harvest techniques and residue management can cause changes in the quantity and quality in soil organic matter (OM). This study aims to assess changes in concentration and in the quality of the OM, in an Ultisol with differents forest residue managements at the beginning of the second rotation. The treatment was: a) elimination of harvest residues and forest floor, bare soil (RE), (b) burning of harvest residues and forest floor and subsequent plowing (IP), (c) maintenance of harvest residues and forest floor on the ground (CP). Soil samples were analyzed for determination of soil organic carbon (OC), carbon in the light fraction (LC) and carbon in the fulvic acids (FA), humic acids (HA) and humins (HU) fractions. The harvest residue conservation did not increase the OC or the LC. There was a loss of the more labile fraction (FA) particularly in IP. The treatments without forest residues and forest floor (RE and IP) show an increase in the degree of stabilization of the OM with an increase HU and in the ratio HA/FA.
Keywords:
humid substances; harvest residues; site preparation; Pinus.