Partitioning of carbon and nitrogen during decomposition of ¹³C¹⁵N‐labeled beech and ash leaf litter

Abstract

The aim of this study was to determine the influence of leaf‐litter type (i.e., European beech—Fagus sylvatica L. and European ash—Fraxinus excelsior L.) and leaf‐litter mixture on the partitioning of leaf‐litter C and N between the O horizon, the topsoil, the soil microbial biomass, and the CO2 emission during decomposition. In a mature beech stand of Hainich National Park, Thuringia, Germany, undisturbed soil cores (∅︁ 24 cm) were transferred to plastic cylinders and the original leaf litter was either replaced by 13C15N‐labeled beech or ash leaf litter, or leaf‐litter‐mixture treatments in which only one of the two leaf‐litter types was labeled. Leaf‐litter‐derived CO2‐C flux was measured every second week over a period of one year. Partitioning of leaf‐litter C and N to the soil and microbial biomass was measured 5 and 10 months after the start of the experiment. Ash leaf litter decomposed faster than beech leaf litter. The decomposition rate was negatively related to initial leaf‐litter lignin and positively to initial Ca concentrations. The mixture of both leaf‐litter types led to enhanced decomposition of ash leaf litter. However, it did not affect beech leaf‐litter decomposition. After 5 and 10 months of in situ incubation, recoveries of leaf‐litter‐derived C and N in the O horizon (7%–20% and 9%–35%, respectively) were higher than in the mineral soil (1%–5% and 3%–8%, respectively) showing no leaf‐litter‐type or leaf‐litter‐mixture effect. Partitioning of leaf‐litter‐derived C and N to microbial biomass in the upper mineral soil (< 1% of total leaf‐litter C and 2%–3% of total leaf‐litter N) did not differ between beech and ash. The results show that short‐term partitioning of leaf‐litter C and N to the soil after 10 months was similar for ash and beech leaf litter under standardized field conditions, even though mineralization was faster for ash leaf litter than for beech leaf litter.

Translocation of 13C-labeled leaf or root litter carbon of beech (Fagus sylvatica L.) and ash (Fraxinus excelsior L.) during decomposition – A laboratory incubation experiment

“…This is supported by the result that the recovery of ash root litter-derived C in C MB is higher than of beech root litter-derived C. No differences were observed in the recovery of root litter-derived C compared to leaf litter-derived C within one species. Further, in agreement with a field decomposition experiment on beech and ash leaf litter (Langenbruch et al, 2014), no differences were observed in the recovery of litter-C in PL-beech leaf and PL-ash leaf , and no mixture effects were observed on the incorporation of ash and beech litter C into MB. The measured recovery of litter C in C MB is an average of all microbial functional groups, as CFE estimates the total MB (Vance et al, 1987;, irrespective of its activity (Bailey et al, 2002).…”

“…Mixture of ash and beech leaf litter led to enhanced mineralization of ash leaf litter but did not affect beech leaf litter mineralization, which agrees with findings of a decomposition experiment in a beech stand (Langenbruch et al, 2014). Several studies found synergistic mixture effects on the decomposition of leaf litter from various tree species, but there also exist studies that found purely additive effects on leaf litter decomposition (H€ attenschwiler et al, 2005).…”

Influence of Litter Diversity on Dissolved Organic Matter Release and Soil Carbon Formation in a Mixed Beech Forest

“…The soil texture in 0–10 cm was characterized as 3% sand, 82% silt and 15% clay [33] . According to Zanella et al [35] , the forest floor was classified as a dysmull (OL + OF) to hemimoder (OL + OF + discontinuous OH) covering a topsoil (0–5 cm) with pH KCl of 3.3 [36] .…”

“…For the experiment, we used leaf litter from European ash ( Fraxinus excelsior L.) and European beech ( Fagus sylvatica L.). Labeled leaf litter was produced in a closed greenhouse with 13 CO 2 -enriched atmosphere (∼300 ‰ V-PDB) for one growing season [36] . As reference litter (unlabeled treatments), leaf litter of beech and ash were collected in the Hainich National Park.…”

Stem injection of 15N-NH4NO3 into mature Sitka spruce (Picea sitchensis)

“…Biomass enriched in 15 N can be produced by application of labelled fertilizers ( Weatherall et al 2006 , Langenbruch et al 2013 ), foliar sprays ( Zeller et al 1998 ) or by direct injections into the plant vascular system ( Swanston and Myrold 1998 ). This latter methodology is potentially most efficient as the valuable 15 N-labelled material is not lost via misting ( Bowden et al 1989 ), exposed to soil sinks ( Nadelhoffer et al 1999 b ) or exported from the immediate area by soil hydrology.…”