Crop and soil nitrogen status of tilled and no-tillage systems in semiarid regions of Saskatchewan
Bibliographic record
Abstract
We examined 1990-1996 crop and soil N data for no-tillage (NT), minimum tillage (MT) and conventional tillage (CT) systems from four long-term tillage studies in semiarid regions of Saskatchewan for evidence that the N status was affected by tillage system. On a silt loam and clay soil in the Brown soil zone, spring what (Triticum aestivum L.) grain yield and protein concentration were lower for NT compared with tilled (CT or MT) systems for a fallow-wheat (F-WM) rotation. Grain protein concentration for continuous wheat (Cont W) was also lower for NT than for MT. For a sandy loam soil in the Brown soil zone, durum (Triticum durum L.) grain protein concentration was similar for MT and NT for both Cont W and F-W, but NT had higher grain yield than MT (P < 0.05 for F-W only). For a loam soil in the Dark Brown soil zone, wheat grain yield for NT was increased by about 7% for fallow-oilseed-wheat (F-O-W) and wheat-oilseed-wheat (W-O-W) rotations. The higher grain yields for NT reduced grain protein concentration by dilution effect as indicated by similar grain N yield. However, at this site, about 23 kg ha -1 more fertilizer N was required for NT than for CT. Elimination of tillage increased total organic N in the upper 7.5 cm of soil and N in surface residues. Our results suggest that a contributing factor to decreased availability of soil N in medium- and fine-textured soils under NT was a slower rate of net N mineralization from organic matter. Soil nitrates to 2.4 m depth did not indicate that nitrate leaching was affected by tillage system. Current fertilizer N recommendations developed for tilled systems may be inadequate for optimum production of wheat with acceptable grain protein under NT is semiarid regions of Saskatchewan. Key words: Tillage intensity, N availability, soil N fractions, N mineralization, crop residue decomposition, grain protein
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.001 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 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 teacher head, 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".