Soil organic constituents as environmental indices to follow the change in soil-environment

1993 Fiscal Year Final Research Report Summary

• Project/Area Number: 04806009
• Research Category: Grant-in-Aid for General Scientific Research (C)
• Allocation Type: Single-year Grants
• Research Field: 土壌・肥料
• Research Institution: Obihiro University of Agriculture and Veterinary Medicine
• Principal Investigator: TSUTSUKI Kiyoshi Obihiro University of Agriculture and Veterinary Medicine, Department of Animal Husbandry, Associate Professor, 畜産学部, 助教授 (80180024)
• Project Period (FY): 1992 – 1993
• Keywords: Soil organic matter / Peat] / Lignin / Fatty acid composition / Sterol / Neutral sugar omposition / Environmental Index

Research Abstract

Interaction between soil and environment was investigated using lignin constituents, fatty acids, sterols, and neutral sugars as environmental indices. Four different types of peat profiles (42 layr-wise samples) and 24 peatland plants were analyzed.
The yield of lignin-derived phenolic compounds was highest in high-moor peat, and decreased in the order of intermediate peat, and low-moor peat. Various quotients between individual phenolic compounds were proved to be good markers indicating the succession of sphagnum moss, grasses and woody plants.
Each peat-land plant had its characteristic fatty acid composition. Phragmites contained a large amount of arachidic acid (C20), which became a good index of low-moor peat. Palmitic acid was dominant in high-moor peat, reflecting the fatty acid composition of sphagnum moss. Saturated fatty acid with chain length shorter than 16, and unsaturated fatty acids with carbon number, were contained in large amounts in peatland plants, but rather unstab le in peat soils. Saturated fatty acids with chain length longer than 20, which are important constituents of plant waxs, increased in peat soils with increasing depth.
Sterols found in peat soils were mainly beta-sitosterol, campesterol, and stigmasterol, which are all plant constituents. Cholesterol, which is animal-origin, was detected in small amounts in low-moor peat formed under very eutrophic environment. The content of sterol was high in the high-moor peat which was dominated by sedges, but decreased in intermediate and low-moor peats in this order. The rate of stigmasterol increased, however, in low-moor peats.
Neutral sugar composition of peat, after acid-hydrolysis, reflected well that of peatland plants. In each profile, glucose was dominant in the top layr but tended to decrease in lower layrs. On the other hand, hemicellulosic sugars (xylose + arabinose) increased in lower layrs.
Thus, the four types of soil organic matter composition in peat soils corresponded well to the dominant plants, pattern of formation, and environment of peatland.