Short-term nitrogen dynamics in a soil amended with anaerobic digestate
Bibliographic record
Abstract
The co-product of anaerobic digestion, digestate, is nitrogen (N) rich; however, the forms and accessibility of this N by the crops have not been fully explored. This study aimed to determine the mineralization parameters of digestate N and to assess its availability for annual ryegrass (Lolium multiflorum Lam.). Four digestate rates of 0 (control), 38, 75, and 150 mg N kg−1 soil (equal to 0, 90, 180, and 360 kg total N ha−1) were applied to a silty clay loam soil in a completely randomized block design with four replications in a greenhouse study. A 100 d aerobic incubation experiment was also conducted with 0 and 150 mg digestate N kg−1 rates at 25 °C. Digestate feedstock included cattle manure (28%), hay (15%), and silage corn (Zea mays L.; 57%). Total plant biomass and N uptake increased linearly with digestate application rate with average apparent N recovery of 37%. Potentially mineralizable N (N0) and mineralizable N rate constant (k) were not significantly different in digestate and control treatments; however, a flush of digestate organic N (30 mg N kg−1) released right after mixing the digestate with soil. Evidences of N immobilization with digestate application were observed in greenhouse study. Majority of plant-available digestate N was in form of NH4+-N; therefore, NH4+-N can be used for estimation of available digestate N for crops. Results need to be validated for specific feedstock and soil properties under field conditions. Further research is needed to assess how long-term build-up of digestate organic N may impact the N availability for crops.
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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) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 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) | 0.000 | 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".