Soil CO2 efflux in a bioenergy plantation with fast-growing Populus trees – influence of former land use, inter-row spacing and genotype

Abstract

AimsIn this study we quantified the annual soil CO2 efflux (annual SCE) of a short rotation coppice plantation in its establishment phase. We aimed to examine the effect of former (agricultural) land use type, inter-row spacing and genotype.MethodsAnnual SCE was quantified during the second growth year of the establishment rotation in a large scale poplar plantation in Flanders. Automated chambers were distributed over the two former land use types, the two different inter-row spacings and under two poplar genotypes. Additional measurements of C, N, P, K, Mg, Ca and Na concentrations of the soil, pH, bulk density, fine root biomass, microbial biomass C, soil mineralization rate, distance to trees and tree diameters were performed at the end of the second growth year.ResultsTotal carbon loss from soil CO2 efflux was valued at 589 g m−2 yr−1. Annual SCE was higher in former pasture as compared to cropland, higher in the narrow than in the wider inter-row spacings, but no effect of genotype was found.ConclusionsSpatial differences in site characteristics are of great importance for understanding the effect of ecosystem management and land use change on soil respiration processes and need to be taken into account in modeling efforts of the carbon balance.

First vs. second rotation of a poplar short rotation coppice: Above-ground biomass productivity and shoot dynamics

“…Once established additional mortality was very low or insignificant. The insignificant change in mortality during the third rotation could partly be attributed to the nutrient-rich soil [12,37], stemming from the year-long fertilization during the former agricultural activities on the land before plantation establishment. The sufficient precipitation in the region also eliminated competition for water (Table S1, supplementary information), and thus droughtinduced mortality.…”

Carbon isotope compositions (δ13C) of leaf, wood and holocellulose differ among genotypes of poplar and between previous land uses in a short‐rotation biomass plantation

“…; Verlinden et al . ). Therefore, the questions addressed were as follows: (1) How do the δ 13 C signals measured in different plant compartments (δ 13 C leaf , δ 13 C wood and δ 13 C holocellulose ) relate mutually?…”

Neglected carbon pools and fluxes in the soil balance of short-rotation woody biomass crops

“…Large quantities of C were sequestered in the root biomass, with 173 g C m À2 in the narrow rows and 127 g C m À2 in the wide rows. Those spatial differences corresponded to the higher soil respiration measured in the narrow rows with respect to the wide rows [23]. Understanding the planting density and spacing as factors of variability helps to reduce uncertainties in quantifying the soil C balance.…”

“…In the double-row POP-FULL plantation, fluxes of C in terms of litter-fall, root production and soil respiration measured in narrow rows and wide rows had different means and a different standard deviation [9,23,24]. Therefore, the samples had to be considered as belonging to different statistical populations, and each data set had to be processed separately.…”