Premium
Substantial net N mineralization during the dormant season in temperate forest soils
Author(s) -
Schütt Marianne,
Borken Werner,
Stange Claus Florian,
Matzner Egbert
Publication year - 2014
Publication title -
journal of plant nutrition and soil science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.644
H-Index - 87
eISSN - 1522-2624
pISSN - 1436-8730
DOI - 10.1002/jpln.201300644
Subject(s) - mineralization (soil science) , beech , soil water , nitrification , nitrogen cycle , cycling , temperate climate , temperate forest , plant litter , environmental science , chemistry , agronomy , environmental chemistry , ecology , nitrogen , soil science , nutrient , forestry , biology , geography , organic chemistry
In temperate forest soils, N net mineralization has been extensively investigated during the growing season, whereas N cycling during winter was barely addressed. Here, we quantified net ammonification and nitrification during the dormant season by in situ and laboratory incubations in soils of a temperate European beech and a Norway spruce forest. Further, we compared temperature dependency of N net mineralization in in situ field incubations with those from laboratory incubations at controlled temperatures. From November to April, in situ N net mineralization of the organic and upper mineral horizons amounted to 10.9 kg N (ha · 6 months) –1 in the spruce soil and to 44.3 kg N (ha · 6 months) –1 in the beech soil, representing 65% (beech) and 26% (spruce) of the annual above ground litterfall. N net mineralization was largest in the Oi/Oe horizon and lowest in the A and EA horizons. Net nitrification in the beech soil [1.5 kg N (ha · 6 months) –1 ] was less than in the spruce soil [5.9 kg N (ha · 6 months) –1 ]. In the range of soil temperatures observed in the field (0–8°C), the temperature dependency of N net mineralization was generally high for both soils and more pronounced in the laboratory incubations than in the in situ incubations. We suggest that homogenization of laboratory samples increased substrate availability and, thus, enhanced the temperature response of N net mineralization. In temperate forest soils, N net mineralization during the dormant season contributes substantially to the annual N cycling, especially in deciduous sites with large amounts of litterfall immediately before the dormant season. High Q 10 values of N net mineralization at low temperatures suggest a huge effect of future increasing winter temperature on the N cycle in temperate forests.