SOIL ORGANIC MATTER FRACTIONS UNDER SECOND-ROTATION EUCALYPTUS PLANTATIONS IN EASTERN RIO GRANDE DO SUL
ABSTRACT The aim of the present study was to evaluate the effect of eucalyptus plantations on total organic C (TOC) and total N (TN) stocks as well as the C and N in the fulvic acid (FA), humic acid (HA), humin (HU), light organic matter (LOM) and microbial biomass (MB) fractions in soils with diffe...
Saved in:
| Published in: | Revista árvore Vol. 41; no. 1 |
|---|---|
| Main Authors: | , , , , , , |
| Format: | Journal Article |
| Language: | English |
| Published: |
Sociedade de Investigações Florestais
01-01-2017
|
| Subjects: | |
| Online Access: | Get full text |
| Tags: |
Add Tag
No Tags, Be the first to tag this record!
|
| Summary: | ABSTRACT The aim of the present study was to evaluate the effect of eucalyptus plantations on total organic C (TOC) and total N (TN) stocks as well as the C and N in the fulvic acid (FA), humic acid (HA), humin (HU), light organic matter (LOM) and microbial biomass (MB) fractions in soils with different textures in the eastern part of the state of Rio Grande do Sul, Brazil. Soil samples were collected from the 0-10-cm, 10-20-cm, 20-40-cm, 40-60-cm and 60-100-cm soil layers in a completely randomized experimental design with subdivided plots. Under the eucalyptus plantation, clay loam soil presented lower HA, HU and MB C stocks in the 0-100-cm soil layer compared to reference vegetation, whereas sandy soil presented higher and C and N in HA and LOM as well as C in MB. The observed increase in TOC in eucalyptus plantations was more pronounced in the surface soil layer (0-10 cm), i.e., approximately 150% higher than under native vegetation, which was probably due to the high contribution of the eucalyptus litter. Differences in C and N stocks in soil organic matter (SOM) fractions between eucalyptus plantations and areas with reference vegetation were more pronounced in sandy soil, showing the capacity of the clay fraction to protect SOM.
RESUMO O objetivo desse trabalho foi avaliar o efeito do cultivo de eucalipto no estoque total de C orgânico (COT) e N total (NT), C e N associados às frações ácido fúlvico (AF), ácido húmico (AH), humina (HU), matéria orgânica leve (MOL) e biomassa microbiana (BM), em solos de diferentes texturas, no Leste do Rio Grande do Sul. O delineamento adotado foi inteiramente casualizado em parcelas subdivididas. As amostras foram coletadas nas camadas de 0-10, 10-20, 20-40, 40-60 e 60-100 cm. Em solo franco-argiloso, a área sob povoamento de eucalipto apresentou redução nos estoques de C associado ao AH, HU e BM em relação à vegetação de referência na camada de 0-100 cm. Por outro lado, no solo arenoso houve aumento nos estoques de COT, NT, C e N associados àAH, HU, MOLe de C-BM. O aumento no estoque de COTfoi principalmente na camada de superficial (0-10 cm), aproximadamente 150 % em relação a área de vegetação nativa, provavelmente devido a grande contribuição do resíduo do eucalipto. Ao comparar as áreas com eucalipto e áreas de vegetação de referência, no solo arenoso, nota-se alterações de maior magnitude nos estoques de C e N associados às frações da MOS, o que evidência a capacidade da fração argila em proteger a matéria orgânica do solo. |
|---|---|
| ISSN: | 1806-9088 1806-9088 |
| DOI: | 10.1590/1806-90882017000100007 |