根际
化学
针铁矿
土壤水分
环境化学
铁酸盐
矿化(土壤科学)
水稻
植物
土壤科学
生物化学
生物
环境科学
吸附
细菌
有机化学
基因
遗传学
作者
Wei Liang,Zhenke Zhu,Bahar S. Razavi,Mouliang Xiao,Maxim Dorodnikov,Lichao Fan,Yuan Huang,Andrey Yurtaev,Yu Luo,Weiguo Cheng,Yakov Kuzyakov,Jinshui Wu,Tida Ge
摘要
Abstract Paddies contain 78% higher organic carbon (C) stocks than adjacent upland soils, and iron (Fe) plaque formation on rice roots is one of the mechanisms that traps C. The process sequence, extent and global relevance of this C stabilization mechanism under oxic/anoxic conditions remains unclear. We quantified and localized the contribution of Fe plaque to organic matter stabilization in a microoxic area (rice rhizosphere) and evaluated roles of this C trap for global C sequestration in paddy soils. Visualization and localization of pH by imaging with planar optodes, enzyme activities by zymography, and root exudation by 14 C imaging, as well as upscale modeling enabled linkage of three groups of rhizosphere processes that are responsible for C stabilization from the micro‐ (root) to the macro‐ (ecosystem) levels. The 14 C activity in soil (reflecting stabilization of rhizodeposits) with Fe 2+ addition was 1.4–1.5 times higher than that in the control and phosphate addition soils. Perfect co‐localization of the hotspots of β‐glucosidase activity (by zymography) with root exudation ( 14 C) showed that labile C and high enzyme activities were localized within Fe plaques. Fe 2+ addition to soil and its microbial oxidation to Fe 3+ by radial oxygen release from rice roots increased Fe plaque (Fe 3+ ) formation by 1.7–2.5 times. The C amounts trapped by Fe plaque increased by 1.1 times after Fe 2+ addition. Therefore, Fe plaque formed from amorphous and complex Fe (oxyhydr)oxides on the root surface act as a “rusty sink” for organic matter. Considering the area of coverage of paddy soils globally, upscaling by model revealed the radial oxygen loss from roots and bacterial Fe oxidation may trap up to 130 Mg C in Fe plaques per rice season. This represents an important annual surplus of new and stable C to the existing C pool under long‐term rice cropping.
科研通智能强力驱动
Strongly Powered by AbleSci AI