Loading…
Microbial use of maize cellulose and sugarcane sucrose monitored by changes in the 13C/ 12C ratio
An arable soil with organic matter formed from C 3-vegetation was amended initially with maize cellulose (C 4-cellulose) and sugarcane sucrose (C 4-sucrose) in a 67-day laboratory incubation experiment with microcosms at 25 °C. The amount and isotopic composition ( 13C/ 12C) of soil organic C, CO 2...
Saved in:
Published in: | Soil biology & biochemistry 2007, Vol.39 (8), p.1888-1896 |
---|---|
Main Authors: | , , |
Format: | Article |
Language: | English |
Subjects: | |
Citations: | Items that this one cites Items that cite this one |
Online Access: | Get full text |
Tags: |
Add Tag
No Tags, Be the first to tag this record!
|
Summary: | An arable soil with organic matter formed from C
3-vegetation was amended initially with maize cellulose (C
4-cellulose) and sugarcane sucrose (C
4-sucrose) in a 67-day laboratory incubation experiment with microcosms at 25
°C. The amount and isotopic composition (
13C/
12C) of soil organic C, CO
2 evolved, microbial biomass C, and microbial residue C were determined to prove whether the formation of microbial residues depends on the quality of the added C source adjusted with NH
4NO
3 to the same C/N ratio of 15. In a subsequent step, C
3-cellulose (3
mg
C
g
−1
soil) was added without N to soil to determine whether the microbial residues formed initially from C
4-substrate are preferentially decomposed to maintain the N-demand of the soil microbial community. At the end of the experiment, 23% of the two C
4-substrates added was left in the soil, while 3% and 4% of the added C
4-cellulose and C
4-sucrose, respectively, were found in the microbial biomass. The addition of the two C
4-substrates caused a significant 100% increase in C
3-derived CO
2 evolution during the 5–33 day incubation period. The addition of C
3-cellulose caused a significant 50% increase in C
4-derived CO
2 evolution during the 38–67 day incubation period. The decrease in microbial biomass C
4-C accounted for roughly 60% of this increase. Cellulose addition promoted microorganisms strongly able to recycle N immediately from their own tissue by “cryptic growth” instead of incorporating NO
3
− from the soil solution. The differences in quality of the microbial residues produced by C
4-cellulose and C
4-sucrose decomposing microorganisms are also reflected by the difference in the rates of CO
2 evolution, but not in the rates of net N mineralization. |
---|---|
ISSN: | 0038-0717 1879-3428 |
DOI: | 10.1016/j.soilbio.2007.02.002 |