Agronomic Values of Anaerobically Digested Cattle Manure and the Separated Solids for Barley Forage Production
Bibliographic record
Abstract
Core Ideas Agronomic values of anaerobically digested solid cattle manure are poorly defined. Separated solids of anaerobically digested cattle manure supplied N similar to cattle manure. Anaerobically digested cattle manure had high NH 4 –N/total N ratio. Anaerobically digested cattle manure had less P buildup than cattle manure. Digestate separated solids can be managed similar to cattle manure. As biogas production expands, digestates from that industry are increasingly available as potential nutrient sources for crop production, but their agronomic value is poorly understood. Thus, a 5‐yr field experiment was conducted to determine the agronomic values of anaerobically digested solid beef cattle feedlot manure (ADM) and the separated solids (SS) from ADM under a semiarid reduced‐tillage dryland barley ( Hordeum vulgare L.) forage cropping system. Three organic amendments, ADM, SS, and undigested solid beef cattle feedlot manure (CM), were applied annually at 200 or 400 kg total N ha −1 for 4 yr, while the residual effect was examined in the fifth year. The higher N and P availability in ADM translated into greater barley forage yields, total N uptake, amendment‐derived N uptake, and apparent N recovery (ANR) from ADM‐amended soil than SS‐ and CM‐amended soils, while there were no significant differences between soils receiving SS or CM. The ANR was 22% for ADM but only 12% for CM and 9% for SS. In contrast, P uptake, the fraction of amendment‐derived P uptake, and apparent P recovery were similar among all amendments. Similar yields, ANR, post‐harvest soil NH 4 , NO 3 , and Olsen‐P concentrations between SS‐ and CM‐amended soils suggest that they have a comparable agronomic value. Less residual Olsen‐P in soil receiving ADM than SS or CM suggests that ADM is a lower risk for P accumulation when applied at N‐based rates. We recommend that current agronomic values for cattle feedlot manure could be applied to SS but not ADM.
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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 | 0.001 | 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".