Soares, Emanuelle Merces Barros  Teixeira, Rafael da Silva  Sousa, Rodrigo Nogueira de  Vasconcelos, Aline de Almeida  Silva, Ivo Ribeiro da  <br/><br/>
Soil Organic Matter Fractions Under Eucalypt Plantation in Reform Management 

<br/><br/> Publicação on-line; 34 ref.; 2 tables; 5 illus.; Summary (En) 
<br/><br/> <br/><br/>ABSTRACT<br/><br/>Harvesting and reform in eucalyptus can lead to changes in soil organic matter (SOM). The objective<br/>of this work was to evaluate the changes in total organic C (TOC) and N (NT), C and N in<br/>humic acid (HA), fulvic acid (FH), light organic matter (LOM) and microbial biomass (MB), in<br/>Ultisol of eucalypt stands over one, two and four years of renovated areas in Rio Grande do Sul<br/>state. After the first year of eucalyptus reform, there were 78% of increases in TOC (0.0-1.0-m<br/>soil layer). After two years, there was an increase in TN and an average reduction of 52% in<br/>LOM-C (0.0-0.1-m soil layer). FA-C, HA-C, and HU-C presented mean reductions of 43 Mg ha–1<br/>(0.0‑1.0-m soil layer) after four years of reform. The litter contribution of previous crop and the<br/>crop residues from the harvest resulted in increments of the SOM fractions. However, there is<br/>a negative effect in later years.<br/><br/>Keywords: forest soils, reform, humic substances, microbial biomass, light organic matter. 
<br/><br/><label>Subjects--Topical Terms: </label><br/>SOLO FLORESTAL<br/>HÚMUS<br/>BIOMASSA<br/>MICROBIOLOGIA DO SOLO