The Role of Soil Organic Matter and Manures in Sustainable Nutrient Cycling - Sustainable Management of Soil Organic Matter - page 248

K. Kaiseret al. Dissolved Organic Nutrients in Shallow Forest Soils

4.4

Dissolved Organic Nutrients
(N, P and S) in Shallow
Forest Soils: Fluxes and
Spectroscopic Characterization

K. K AISER , G. G UGGENBERGER AND W. Z ECH

Institute of Soil Science and Soil Geography, University of
Bayreuth, D-95440 Bayreuth, Germany

Introduction

Dissolved organic matter (DOM) contains important nutrients such as N,
P and S. There is little vertical loss of the organic nutrients from deeply
developed forest soils under cool and temperate climates due to effective
retention of DOM in the sub-soil (McDowell and Likens, 1988; Qualls and
Haines, 1991). In contrast to deeply developed soils, the lower horizons of
shallow soils sorb relatively little DOM (Kaiser et al ., 1996). Thus, shallow
forest soils might release large amounts of dissolved organic carbon (DOC)
and associated dissolved organic nutrients such as N, P and S (DON, DOP
and DOS) into aquatic environments. We tested this hypothesis in a field
experiment.

Materials and Methods

Experimental site

The experimental site was located in NE Bavaria, Germany. The site
was on a flat hilltop covered with a 90-year-old European beech ( Fagus
sylvatica L.) forest. The soils were Lithic Rendolls derived from Upper
Kimmeridgian dolomite. The basic properties of the soils are summarized
in Table 4.4.1. Due to the loamy texture and the large organic carbon
(OC) content, the soils were strongly aggregated. In addition, there were
flow channels throughout the whole profile resulting from preferential