Root biomass and soil carbon distribution in hybrid poplar riparian buffers, herbaceous riparian buffers and natural riparian woodlots on farmland
Bibliographic record
Abstract
The objectives of this study were to compare coarse root (diameter > 2 mm) and fine root (diameter < 2 mm) biomass, as well as distribution of soil carbon stocks in 3 types of riparian land uses across 4 sites located in farmland of southern Québec, Canada: (1) hybrid poplar buffers (9th growing season); (2) herbaceous buffers; (3) natural woodlots (varying in tree species and age). For all land uses most of the root biomass was within the 0-20 cm depth range. Total coarse root biomass, to a 60 cm depth, ranged from 8.8-73.7 t/ha in woodlots, 0.6-1.3 t/ha in herbaceous buffers, and 9.2-27.3 t/ha in poplars. Total fine root biomass ranged from 2.68-8.64 t/ha in woodlots, 2.60-3.29 t/ha in herbaceous buffers, and 1.86-2.62 t/ha in poplars. Total root biomass was similar or higher in poplar buffers compared to a 27 year-old grey birch forest. This indicates that poplar buffers accelerated riparian soil colonisation by roots compared to natural secondary succession. Generally, fine root biomass in the surface soil (0-20 cm) was lower in poplar than in herbaceous buffers; the reverse was observed at greater depth. Highest coarse root biomass in the 40-60 cm depth range was observed in a poplar buffer, highlighting the deep rooted nature of poplars. On average, total soil C stocks (0-60 cm) were greater in woodlots than in riparian buffers. On most sites, soil C stocks tended to be lower in poplar buffers compared to adjacent herbaceous buffers, especially in surface soil, probably because of lower fine root biomass in poplar buffers. Across all sites and land uses, highest soil C stocks at the different soil depths were found in the soil layers of woodlots that also had the greatest fine root biomass. Strong positive linear relationships between fine root biomass and soil C stocks in the 0-20 cm depth range (R (2) = 0.79, p < 0.001), and in the whole soil profile (0-60 cm) (R (2) = 0.65, p < 0.01), highlight the central role of fine root biomass in maintaining or increasing soil C stocks.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".