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Transformation and stabilization of pyrogenic organic matter in a temperate forest field experiment
被引:89
作者:
Singh, Nimisha
[1
]
Abiven, Samuel
[1
]
Maestrini, Bernardo
[1
]
Bird, Jeffrey A.
[2
]
Torn, Margaret S.
[3
]
Schmidt, Michael W. I.
[1
]
机构:
[1] Univ Zurich, Dept Geog, CH-8057 Zurich, Switzerland
[2] CUNY Queens Coll, Sch Earth & Environm Sci, Flushing, NY 11367 USA
[3] Univ Calif Berkeley, Lawrence Berkeley Natl Lab, Berkeley, CA 94720 USA
基金:
瑞士国家科学基金会;
关键词:
soil organic matter;
nitrogen deposition;
15N;
density fractionation;
priming effect;
microbial biomass;
13C;
pyrogenic organic matter;
benzene polycarboxylic acids;
SOIL MICROBIAL BIOMASS;
BLACK CARBON CONTRIBUTION;
FAST-PYROLYSIS BIOCHAR;
COARSE WOODY DEBRIS;
NITROGEN DEPOSITION;
FUMIGATION EXTRACTION;
LITTER DECOMPOSITION;
DECIDUOUS FOREST;
CHARCOAL;
DYNAMICS;
D O I:
10.1111/gcb.12459
中图分类号:
X176 [生物多样性保护];
学科分类号:
090705 ;
摘要:
Pyrogenic organic matter (PyOM) decomposes on centennial timescale in soils, but the processes regulating its decay are poorly understood. We conducted one of the first studies of PyOM and wood decomposition in a temperate forest using isotopically labeled organic substrate, and quantified microbial incorporation and physico-chemical transformations of PyOM in situ. Stable-isotope (C-13 and N-15) enriched PyOM and its precursor wood were added to the soil at 2cm depth at ambient (N0) and increased (N+) levels of nitrogen fertilization. The carbon (C) and nitrogen (N) of added PyOM or wood were tracked through soil to 15cm depth, in physically separated soil density fractions and in benzene polycarboxylic acids (BPCA) molecular markers. After 10months in situ, more PyOM-derived C (>99% of initial C-13-PyOM) and N (90% of initial N-15-PyOM) was recovered than wood derived C (48% of C-13-wood) and N (89% under N0 and 48% under N+). PyOM-C and wood-C migrated at the rate of 126mmyr(-1) with 3-4% of PyOM-C and 4-8% of wood-C recovered below the application depth. Most PyOM C was recovered in the free light fraction (fLF) (74%), with 20% in aggregate-occluded and 6% in mineral associated fractions - fractions that typically have much slower turnover times. In contrast, wood C was recovered mainly in occluded (33%) or dense fraction (27%). PyOM addition induced loss of native C from soil (priming effect), particularly in fLF (13%). The total BPCA-C content did not change but after 10months the degree of aromatic condensation of PyOM decreased, as determined by relative contribution of benzene hexa-carboxylic acid (B6CA) to the total BPCA C. Soil microbial biomass assimilated 6-10% of C from the wood, while PyOM contributions was negligible (0.14-0.18%). The addition of N had no effect on the dynamics of PyOM while limited effect on wood.
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页码:1629 / 1642
页数:14
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