Soil organic matter formation and loss are mediated by root exudates in a temperate forest
Soil organic matter formation and loss are mediated by root exudates in a temperate forest
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温带森林中土壤有机质的形成和损失是由根系分泌物介导的
DOI：
10.1038/s41561-022-01079-x
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发表时间：
2022-11-28
影响因子：
18.3
通讯作者：
Taylor, Benton N.
中科院分区：
文献类型：
--
作者：
Chari, Nikhil R.;Taylor, Benton N.
根分泌物的数量和组成低分子量的碳化合物从活植物根系释放到土壤中，预计将转移全球变化，越来越多的工作表明，根分泌物对稳定的土壤有机质动态有重要影响。然而，大多数关于渗出物对土壤有机质影响的研究使用高度均质化或人工土壤，在渗出物如何影响天然完整土壤系统中的碳动态方面存在重大不确定性。我们使用C-13-标记的人工根系分泌物，以研究稳定的土壤有机质的形成和损失在完整的森林土壤芯收集在一个异质梯度在温带阔叶林的分泌速率和类型的影响。我们观察到不同的渗出物处理对稳定的土壤碳动态的影响，凌驾于原生土壤的异质性，和较高的渗出率增强矿物相关的有机质周转，但不积累。有机和氨基酸渗出物导致净矿物质相关的有机物积累，与氨基酸有特别强的积极影响微生物生物量。单糖增加矿物相关的有机物营业额（形成和损失），但没有改变这个池的大小。我们的研究结果表明，在全球变化下，根系分泌速率的增加和向单糖的成分转移可能会降低土壤的C储存能力。根据一项使用温带森林完整土芯的人工根系分泌物实验，从植物根系释放到土壤中的碳化合物的数量和组成影响土壤碳的形成和损失。
The amount and composition of root exudates-low-molecular-weight carbon compounds released from living plant roots into soil-are expected to shift under global change, and a growing body of work indicates that root exudates have important impacts on stable soil organic matter dynamics. However, most research on exudate effects on soil organic matter uses highly homogenized or artificial soil, leaving major uncertainties in how exudates will influence carbon dynamics in natural, intact soil systems. We used C-13-labelled artificial root exudates to examine the effects of exudation rate and type on stable soil organic matter formation and loss in intact forest soil cores collected over a heterogeneous gradient in a temperate hardwood forest. We observed effects of different exudate treatments on stable soil carbon dynamics that overrode native soil heterogeneity, and higher exudation rates enhanced mineral-associated organic matter turnover but not accumulation. Organic and amino acid exudates led to net mineral-associated organic matter accumulation, with amino acids having particularly strong positive effects on microbial biomass. Simple sugars increased mineral-associated organic matter turnover (both formation and loss) but did not alter the size of this pool. Our results suggest that predicted increases in root exudation rates and compositional shifts towards simple sugars under global change may reduce soils' C storage capacity.The amount and composition of carbon compounds released from plant roots into soil influences soil carbon formation and loss, according to an artificial root exudate experiment using intact soil cores from a temperate forest.