Lignin Signature in Soils of Shrub Patches in Northeastern Patagonia

Abstract

The objective of this research was to determine the degree of decomposition and alteration of lignin in soils of two types of shrub patches , featured by the dominant species (Prosopis alpataco and Atriplex lampa) in the northeastern Patagonian region . These species have been widely utilized in land reclamation programs mainly in west and south - central Argentina . Shrub patches of both species showed different characteristics in relation to variations in the contents of polysaccharides and lignin . There were different patterns of polysaccharides and lignin distribution in both patches and in climatic seasons . Lignin concentration changes are evidence that there is a transformation in structural units when its units (vanillyl, syringyl, and cinnamyl) lose phenolic groups during oxidation, as depth in the sampled mineral soil is increased . Polysaccharides and lignin dynamics showed a temporary variability of litter quality when the total primary production , decomposition , and mineralization were different in both types of patches . The lignin decomposition pattern under aerobic conditions involves type of litter materials in patches , influ ence of the contribution of surface and subsurface roots (above ground and below ground litter), environmental conditions , and precipitation of fragments decomposed from lignin in soil solution .