Phenolic and carbohydrate signatures of organic matter in soils developed under grass and forest plantations following changes in land use

Abstract

Comparisons were made between the phenolic and carbohydrate signatures of soil profiles developed under grass, spruce and ash stands. Samples were collected from a brown earth soil which was originally under the same land use, but over the past 43 years has supported different monocultures. Distinct signatures associated with each litter type were recorded in individual profiles. A relatively undecomposed phenolic fraction from lignin and hydrolysable carbohydrate fraction from plants had accumulated in the soils under spruce and ash. This largely reflected the quantity and quality of the litter inputs from the spruce and ash compared with the grass. The phenolic and hydrolysable carbohydrate fractions accounted for as much as 60% of the total organic carbon concentration in the deep horizons. In the grassland profile both fractions were more decomposed than under ash and spruce suggesting that the forest profiles had rapidly accumulated a carbon pool with a comparatively slow rate of decomposition. This was most apparent from the spruce profile (which contained 398 mg g-' C carbohydrate hydrolysed using trifluoracetic acid (TFA) in the C horizon compared with 165 and 45 mg g-' C under ash and grass respectively). We conclude that the decay rate of these fractions is a function of the vegetation type.

Dissolved organic matter sources in large Arctic rivers

“…This indicates significant input of woody plant 528 material as a source of lignin phenols. It has been indicated that C/V ratios decrease with 529 progressive degradation, but in our data set the C/V ratios were actually higher in older DOC 530 ( In addition, p-coumaric acid is believed to be more soluble (Sanger et al, 1997). Both of these 540 processes lead to higher CAD/FAD ratios in river DOM.…”

Enzymatic Degradation of Lignin in Soil: A Review

“…The lignin content in the soil decreases from the upper soil horizon to the lower soil horizon. However, in a few cases, an increase in lignin content of soil organic matter (SOM) with depth has been observed [23][24][25]. Lignin distribution in soil could also vary with location.…”

Fenóis derivados da lignina, carboidratos e aminoaçúcares em serapilheira e solos cultivados com eucalipto e pastagem

“…Sanger et al (1997) descreveram a maior abundância desses compostos na serapilheira de pastagem e indicaram esse resultado como característico dessa cobertura. Mesmo assim, neste trabalho verificou-se maior teor de VSC (somatório) nos galhos da serapilheira de eucalipto, seguido pela serapilheira da pastagem e daquela dos resíduos mais finos de eucalipto (galhos finos, folhas e casca).…”

“…Sanger et al (1997) também verificaram resultado similar, em que a relação H/P foi menor que 0,2 na serapilheira de pastagem e próximas a 0,8 no de plantas florestais de Picea abies, com resíduos mais lenhosos. Possivelmente, a maior labilidade e superfície de contato dos resíduos finos com enzimas decompositoras de celulose e hemicelulose tenham contribuído para tal resultado.…”