Lipid abundance and composition of a humic Oxisol as a function of land use

Scientia Agricola

Cristiane Pereira De Assis²  Francisco Javier González-vila¹  Ivo Jucksch¹  Jose Antonio González-pérez¹  Júlio César Lima Neves¹  João Luis Lani¹  Eduardo De Sá Mendonça¹ 

[1] ,Universidade Federal do Vale do São Francisco, CeagroPetrolina PE ,Brasil

关键词: soil and litter lipid;    soil management;    tropical soil;    grass;    coffee;    lípidios do solo e serapilheira;    manejo do solo;    solo tropical;    pastagem;    cafeicultura;   

DOI  :  10.1590/S0103-90162011000200014

来源: SciELO

【 摘 要 】

Soil organic matter of a humic Oxisol has been characterized by analyzing litter and soil lipid composition under vegetal covers (coffee, pasture and fragment of native forest). Soil and litter samples were collected from each site at two depths (0-10 and 60-100 cm). Lipid composition was determined by gas chromatography-mass spectrometry (CG-MS). In the solvent extracts of the soil lipids, even-numbered n-alkanoic acids in the range of C16-C32 indicate a soil organic matter input from higher plant waxes. The major compound classes in both the soil and the litter included saturated n-alkanoic acids, with average values in the total spectrum of 58 and 53%, respectively Clear differences in lipid composition were found between the topsoil and subsurface. Long chain alkylic compounds (alkanoic acids and alkanes) accumulated preferably at depths of 60-100 cm. On the surface, the soil from natural vegetation had a total lipid value higher than those cultivated soils, and showed a predominance of unsaturated alkanoic acids at 60-100 cm. Preservation of alkylic moieties with depth was observed under forest and pasture, indicating that these systems of land use are prone to lipid accumulation. Lipids, especially the long-chain (> C20) ones, may be important with regard to C stabilization and humification processes in subsoil of humic Oxisols, highlighting the importance of lipids compounds in the bulk structure of organic matter these soils.

【 授权许可】

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