Soil microbial populations, activity, and community structure in continuous corn or forage systems under organic or inorganic fertilization in eastern Canada
Bibliographic record
Abstract
Succession of soil microbial communities proceeds interdependently with crop development under the control of edaphic, agricultural, and climatic conditions. Soil microbial community composition and activity were characterized in two managed cropping systems (continuous corn or mixed forage) receiving liquid hog manure (LHM) or inorganic fertilization (IF) since 1989. Microbial community composition was determined from patterns of phospholipid fatty acids (PLFA). Soil microbial biomass C, enzymatic activity, and total phospholipids were greater under forage than under continuous corn. Principal component analysis (PCA) revealed a high degree of variation in PLFA composition and microbial community structure due to treatments and time of sampling. The first two PCA axes explained 80 to 90% of the variability on all sampling dates. Two main groups were created along the first component, the first comprising all forage treatments and a second with LHM-treated continuous corn. The IF and control-treated continuous corn were differentiated from all others on the second component. All groups were characterized by specific microbial communities. The most significant shift in specific groups of fatty acids was caused by LHM addition to continuous corn, especially due to the relative abundance of the fungal fatty acid 18:29,12. Our findings indicated that the addition of organic materials, rich in available C and N, induced development of diverse microbial populations, which can be successfully monitored by phospholipid fatty acid prof iles. Key words: Microbial community, phospholipid fatty acid profiles, hog manure, corn, forage
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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 | 0.001 | 0.000 |
| Scholarly communication | 0.001 | 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".