Soil‐ and Plant‐Based Indices in Potato Production in Response to Polymer‐Coated Urea
Bibliographic record
Abstract
Polymer‐coated urea (PCU) is used in potato (Solanum tuberosum L.) production to maintain or improve tuber yield while minimizing N losses, but the mode of N release is different from conventional soluble N sources. Hence, it is not known how soil‐ and plant‐based indices of N availability would perform in response to PCU application. A 3‐yr study was conducted on a sandy‐loam soil in Quebec, Canada, to examine the effect of PCU application rate (0, 60, 120, 200, and 280 kg N ha−1) on petiole NO3–N concentrations, chlorophyll meter readings (SPAD readings), soil mineral N content, and total tuber yield. Nitrate availability throughout the growing season was monitored by measuring NO3 adsorbed by anion exchange membranes (NO3AEM). The NO3AEM values, petiole NO3–N concentrations, SPAD readings, soil mineral N content, and total tuber yield increased with PCU application rate. The NO3AEM values fluctuated during the growing season due to plant N uptake and variations in soil moisture content. Using all the PCU rates across years, we found that relative yield was better related to petiole NO3–N concentrations measured at 45 to 50 d after planting (DAP) (R2 = 0.95) and to cumulative NO3AEM values measured up to 49 DAP (R2 = 0.91) than soil mineral N (R2 = 0.67), soil NO3–N (R2 = 0.65), and SPAD readings (R2 = 0.53) measured at 45 to 50 DAP, respectively. This study showed that soil‐ and plant‐based indices of N availability can be used as early indicators of yield response in potato fertilized with PCU.
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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 | 0.001 |
| 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 | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| 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".