Nitrate leaching from residual fertilizer N after spring thaw in two corn agro-ecosystems
Bibliographic record
Abstract
Water samples at zero tension were collected using an open-ended lysimeter and analyzed for NO3−-N from a Chicot sandy clay loam and a Ste. Rosalie clay soil under continuous corn (Zea mays L.) in 1993 and 1994, shortly after spring thaw. There was negligible leaching of NO3−-N at previous fertilizer N rates of 0 and 170 kg ha-1 in both soils. However, NO3−-N concentrations of the leachates from soils receiving 285 and 400 kg N ha-1 yr-1 varied from 1.4 to 80 mg L-1, depending on the initial levels of soil residual NO3−-N and the supply of percolation water. When the initial levels of soil NO3−-N were relatively high and percolation of water was relatively slow in 1993, NO3−-N concentrations of the leachates ranged from 20 to 80 mg L-1. Nitrite-N concentrations were from 1.4 to 15.6 mg L-1 when the initial levels of soil residual NO3−-N were relatively low and percolation was relatively fast in 1994. The occasional higher NO3−-N concentrations in the leachate from the previous higher N applications indicated a potential for contaminating surface and ground waters as a result of NO3−-N leaching in the early spring. Key words: Residual N, nitrate-N leaching, soil solution, continuous corn, N fertilization
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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 | 0.001 | 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) | 0.000 | 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".