Earth's Systems / Biological processes / Terrestrial ecosystem functioning / Decomposition / Litter quality (lignin:N) sets the decay trajectory
Litter quality (lignin:N) sets the decay trajectory
How litter chemistry sets the speed and phases of decay: an early phase on soluble sugars and cellulose, then a late phase limited by lignin and by nitrogen supply, with litter N concentration rising as carbon is lost.
Boundary: where this process starts
Starts with: Soluble sugars and cellulose are consumed first (fast early phase)
Boundary: where it ends
Ends after: Lignin-rich residue persists and decay slows toward a limit value (late phase)
Line thickness = size of impact (1 to 5)% on a line = chance a fork takes that branch📄 = pieces of evidence on a stepNegative effectLoops backHypothesisResource used up (arrow into the step)Resource used, not used upResource made or released (arrow out of the step)
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- Participant
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- Resource
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- Step
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- Decision fork
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- Loop
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- Size of impact
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- Boundary
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- Description
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- Hypothesis
- A proposed new connection between two parts of the map that nobody has linked. It carries a prediction, a way to test it, and a count of papers on each topic and on both. It is an unverified idea until someone tests it.
Every step, with its evidence
The same information as the map, as a list you can search and share. Click a participant or resource to see everywhere it appears.
Soluble sugars and cellulose are consumed first (fast early phase)
Evidence (1) · added by Skeptic
- Berg 2014, doi:10.1016/j.soilbio.2014.08.005: The early phase of foliar litter decay is dominated by loss of soluble and cellulose-like compounds. (confidence 0.8)
⑂ Does the litter supply enough N for the microbial demand?
Evidence (1) · added by Skeptic
- Parton et al. 2007, Global-scale similarities in nitrogen release patterns during long-term decomposition, Science, doi:10.1126/science.1134853: Across 21 sites litter first immobilizes N and later releases it; low-N litter spends longer in net immobilization. Split here (55/45) is an estimate for mixed temperate litter. (confidence 0.45)
N-poor litter: microbes import soil N and net immobilization occurs
Evidence (1) · added by Skeptic
- Parton et al. 2007, doi:10.1126/science.1134853: Initial net N immobilization precedes release in litter with low initial N. (confidence 0.7)
N-rich litter: surplus N is released as ammonium early
Evidence (1) · added by Skeptic
- Zhang et al. 2008, Rates of litter decomposition in terrestrial ecosystems: global patterns and controlling factors, J Plant Ecology, doi:10.1093/jpe/rtn002: Litter with higher N and lower lignin and C:N decays faster and releases N sooner. (confidence 0.75)
Lignin-rich residue persists and decay slows toward a limit value (late phase)
Evidence (1) · added by Skeptic
- Berg 2014, doi:10.1016/j.soilbio.2014.08.005: Late-stage decay is regulated by lignin and slows towards a limit value rather than to zero residue. (confidence 0.8)
High mineral N suppresses ligninolytic phenol oxidase in lignin-rich litter
Evidence (1) · added by Skeptic
- Carreiro et al. 2000, Microbial enzyme shifts explain litter decay responses to simulated nitrogen deposition, Ecology, doi:10.1890/0012-9658(2000)081[2359:meseld]2.0.co;2: Experimental N addition lowered phenol oxidase activity and slowed late-stage decay of high-lignin litter, while raising cellulase activity in low-lignin litter. (confidence 0.85)