Pinus afforestation in South Brazilian highlands: soil chemical attributes and organic matter composition

Scientia Agricola

Deborah Pinheiro Dick²  Simone Benvenuti Leite²  Ricardo Simão Diniz Dalmolin¹  Henrique Cesar Almeida¹  Heike Knicker¹ 

[1],UFRGS Inst. de Química Depto. de Físico-QuímicaPorto Alegre RS ,Brasil

关键词: FTIR spectroscopy;    humification;    exchangeable cation;    pastures;    recalcitrance;    espectroscopia de FTIR;    humificação;    cátion trocável;    pastagens;    recalcitrância;   

DOI  :  10.1590/S0103-90162011000200007

来源: SciELO

【 摘 要 】

In the last three decades, exotic tree species are being introduced in the natural pastures of the highlands located at the northeastern part of Rio Grande do Sul State (RS), Brazil. This alteration of land use may impart drastic changes in the soil attributes. In this context, this work aimed to evaluate the impact of Pinus taeda afforestation on soil chemical attributes and organic matter (SOM) composition in Leptosols from Campos de Cima da Serra, RS. Soil samples under eight year old (Pi8) and 30 year old (Pi30) Pinus plantations and under native pasture (NP) were studied. Contents of exchangeable cations and of micronutrients and soil pH were determined. The SOM composition was investigated by means of elemental analyses and FTIR spectroscopy. The soil under pasture had a higher content of nutrients and of SOM in comparison to Pinus soils, reflecting the higher input and decomposition rate of the below ground added residue in the grassland environment. The SOM in pasture soils showed a higher content of carbohydrate and of structures derived from microbial metabolism. Besides the depletion of nutrients and of SOM, Pinus afforestation affected the SOM quality: following afforestation, the proportion of chemically recalcitrant structures and of carboxylic groups increased, whereas N-containing groups decreased.

【 授权许可】

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