Effect of tree species substitution on organic matter biodegradability and mineral nutrient availability in a temperate topsoil

Abstract

In the Breuil-Chenue experimental site (Morvan, France), the native forest, a 150-year-old coppice with standards dominated by beech was partly clear-cut thirty years ago and replanted with several tree species. Soil samples were collected from the A1 horizon, in the 0-5 cm layer of the preserved native forest and three plantations: European beech, Douglas-fir and Norway spruce. Aliquots of 0-2 mm sieved soils were incubated for 40 days under laboratory conditions (15°C, water-holding capacity). Carbon-mineralization was monitored; mineral nitrogen, water-extractable organic carbon and mineral elements were determined before and after the incubation. The release of CO 2 decreased in the order: spruce > native forest > beech > Douglas-fir, whereas nitrogen net mineralization decreased in the opposite order. Douglas-fir and beech soils were characterised by high nitrification activity and high solubilization of Ca, Mg, and Mn. Native forest and spruce soils were characterized by low nitrification activity, high carbon-mineralization and high solubilization of Fe and Al. © INRA, EDP Sciences, 2006.