Open AccessSoil carbon changes under M iscanthus driven by C 4 accumulation and C 3 decompostion – toward a default sequestration function
Author(s) -
Poeplau Christopher,
Don Axel
Publication year - 2014
Publication title -
gcb bioenergy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.378
H-Index - 63
eISSN - 1757-1707
pISSN - 1757-1693
DOI - 10.1111/gcbb.12043
Subject(s) - carbon sequestration , soil carbon , bioenergy , greenhouse gas , carbon fibers , miscanthus , environmental science , perennial plant , climate change , agronomy , chemistry , carbon dioxide , renewable energy , soil science , ecology , soil water , mathematics , biology , algorithm , composite number , organic chemistry
Bioenergy has to meet increasing sustainability criteria in the EU putting conventional bioenergy crops under pressure. Alternatively, perennial bioenergy crops, such as M iscanthus , show higher greenhouse gas savings with similarly high energy yields. In addition, M iscanthus plantations may sequester additional soil organic carbon ( SOC ) to mitigate climate change. As the land‐use change in cropland to M iscanthus involves a C 3 ‐C 4 vegetation change ( VC ), it is possible to determine the dynamic of Miscanthus ‐derived SOC (C 4 carbon) and of the old SOC (C 3 carbon) by the isotopic ratio of 13 C to 12 C. We sampled six croplands and adjacent M iscanthus plantations exceeding the age of 10 years across Europe. We found a mean C 4 carbon sequestration rate of 0.78 ± 0.19 Mg ha −1 yr −1 , which increased with mean annual temperature. At three of six sites, we found a significant increase in C 3 carbon due to the application of organic fertilizers or difference in baseline SOC , which we define as non‐ VC ‐induced SOC changes. The R othamsted Carbon Model was used to disentangle the decomposition of old C 3 carbon and the non‐ VC ‐induced C 3 carbon changes. Subsequently, this method was applied to eight more sites from the literature, resulting in a climate‐dependent VC ‐induced SOC sequestration rate (0.40 ± 0.20 Mg ha −1 yr −1 ), as a step toward a default SOC change function for M iscanthus plantations on former croplands in E urope. Furthermore, we conducted a SOC fractionation to assess qualitative SOC changes and the incorporation of C 4 carbon into the soil. Sixteen years after M iscanthus establishment, 68% of the particulate organic matter ( POM ) was M iscanthus ‐derived in 0–10 cm depth. POM was thus the fastest cycling SOC fraction with a C 4 carbon accumulation rate of 0.33 ± 0.05 Mg ha −1 yr −1 . M iscanthus ‐derived SOC also entered the NaOCl‐resistant fraction, comprising 12% in 0–10 cm, which indicates that this fraction was not an inert SOC pool.