Sequestration of C in soils under Miscanthus can be marginal and is affected by genotype-specific root distribution
Sequestration of C in soils under Miscanthus can be marginal and is affected by genotype-specific root distribution
复制标题
DOI：
10.1016/j.agee.2014.11.011
复制
发表时间：
2015-02-01
影响因子：
6.6
通讯作者：
Goulding, Keith W. T.
中科院分区：
文献类型：
--
作者：
Richter, Goetz M.;Agostini, Francesco;Goulding, Keith W. T.
芒草是一种低投入的能源作物，适合于低肥力的边际耕地，并被认为提供土壤中的碳固定。我们分析了一个长期的田间试验（14年），以确定是否在不同的芒草基因型，生长习性和根系分布的差异影响土壤碳空间。从中心和径向取土芯，深度为1 m，并分为6个垂直段。直接测定了土壤总根长（TRL）、根干物质（RDM）和δ C-13标记的土壤有机碳（SOC），并计算了根长密度（RLD）、由此导出的土壤有机碳（SOCM）和残余土壤碳（SOCorig）。发现基因型对SOC的空间分配具有统计学显著影响。将SOC品种分为“成簇”（T）和“非成簇”（NT）表型表明，14年来各组累积的RDM量相似（分别为11.4 +/- 3.3和11.9 +/- 4.8 Mg ha（-1））。然而，表型T分配更多的碳比NT（33%比25%）的根在底土中。在同一时期，芒草基因型固碳量为4.2 ~ 7.1 g/kg土壤，高于C-3源有机碳的平均流失量（3.25 g/kg）。芒草下“A层”的碳储存比基线增加了约5兆公顷（-1），而底土的净增加微不足道。下层土壤中芒草根碳的量很小（1.2-1.8 Mg C ha（-1）），但对于可持续的固碳可能很重要，因为根密度（RLD）解释了SOCM的高百分比（R-2 = 0.66）。(C)2014作者由爱思唯尔公司出版
Miscanthus is a low input energy crop suitable for low fertility marginal arable land and thought to provide carbon sequestration in soil. We analysed a long-term field experiment (14-year) to determine whether differences in genotype, growth habit, and root distribution affected soil carbon spatially under different Miscanthus genotypes. Soil cores were taken centrally and radially to a depth of 1 m, and divided into six vertical segments. Total root length (TRL), root dry matter (RDM) and delta C-13 signature of soil organic carbon (SOC) were measured directly, and root length density (RLD), fractions of Miscan thusderived soil organic C (SOCM), and residual soil carbon (SOCorig) were calculated. Genotype was found to exhibit a statistically significant influence on spatial allocation of SOC. Grouping varieties into 'tuftforming' (T) and 'non-tuft-forming' (NT) phenotypes revealed that respective groups accumulated similar amounts of RDM over 14 years (11.4 +/- 3.3 vs. 11.9 +/- 4.8 Mg ha(-1), respectively). However, phenotype T allocated more carbon to roots in the subsoil than NT (33% vs. 25%). Miscanthus genotypes sequestered between 4.2 and 7.1 g C-4-SOC kg(-1) soil over the same period, which was more than the average loss of C-3-derived SOC (3.25 g kg(-1)). Carbon stocks in the 'A horizon' under Miscanthus increased by about 5 Mg ha(-1) above the baseline, while the net increase in the subsoil was marginal. Amounts of Miscanthus root C in the subsoil were small (1.2-1.8 Mg C ha(-1)) but could be important for sustainable sequestration as root density (RLD) explained a high percentage of SOCM (R-2 = 0.66). (C) 2014 The Authors. Published by Elsevier B.V.