Plowing a Poorly Drained Grassland Reduced Soil Respiration
Bibliographic record
Abstract
Managed grasslands are a predominant land use in northern temperate regions. They are often on poorly drained soils and contain large stocks of soil organic carbon (SOC). It is important to understand C dynamics in grasslands to better assess their role in regional C budgets. Two adjacent grassland plots, one amended with 100 m 3 ha −1 of liquid swine manure (LSM) annually since 1978, and another unamended were killed by glyphosate in the autumn or (i) left with vegetation intact. Those killed were either (ii) left as an undisturbed chemical fallow, (iii) plowed by full‐inversion tillage (FIT) in the autumn, or (iv) in the spring. Following the autumn plowing, we monitored CO 2 emissions from the fallow soil surface, CO 2 concentrations in the soil profile, soil temperature, and soil water content for 1 yr. Changes in soil aggregation, the light fraction organic matter, and microbial biomass were also monitored. Plowing decreased the total microbial biomass on average by 27 g C m −2 , the quantity of water‐stable aggregates by 7 to 12% and with it the concentration of light fraction organic matter. Respiration was also reduced by 142 g CO 2 ‐C m −2 by autumn‐FIT and 175 g CO 2 ‐C m −2 by spring‐FIT on unamended soils, and 90 g CO 2 ‐C m −2 by autumn‐FIT and 98 g CO 2 ‐C m −2 by spring‐FIT on amended soils. Regression analyses suggested that reductions in CO 2 emissions were due to the placement of surface SOC at depth where soil temperature and oxygen availability were attenuated. In these soils, the cool humid conditions at depth in the soil profile may act to counter‐balance the physical effects of tillage thereby preserving C deep in the soil profile. Effective calculation of C budgets and changes in SOC stocks depends on the ability to reproduce the interaction between climate, soil type, land use, and management action. A more complete understanding of the effect of management actions that modify the vertical distribution of biogeochemical (particularly organic C) and environmental parameters on soil respiration in poorly drained soils is required.
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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 | 0.000 | 0.000 |
| 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) | 0.002 | 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".