Quantification of Groundwater Nitrate Loading after Raspberry Field Renovation Using High‐Resolution Passive Diffusion Sampling
Bibliographic record
Abstract
The Abbotsford‐Sumas Aquifer is a permeable, unconfined aquifer in British Columbia, Canada, where raspberry ( Rubus idaeus L.) production is an important source of groundwater NO 3 contamination. Renovation of raspberry fields (i.e., canes chopped, soil tilled and fumigated, and spring manure application prior to replanting), which typically occurs every 6 to 10 yr in response to decreased crop vigor, has been suggested as a possible cause of significant interannual variation in groundwater NO 3 concentrations. This study used high‐resolution passive diffusion sampling to quantify the magnitude and timing of NO 3 loading to shallow groundwater from a commercial raspberry field during a 6‐yr (2009–2015) monitoring period after crop renovation. After renovation, the annual NO 3 loading increased from ∼95 kg N ha −1 in Year 1 to ∼245 kg N ha −1 in Year 2 and decreased to ∼85 kg N ha −1 in Year 3. The average annual NO 3 loading from Years 4 to 6 (72 kg N ha −1 ) was assumed to reflect annual loading without a renovation effect, and the increased loading during Years 1 to 3 was attributed to renovation. Renovation contributed an estimated 33 to 23% of total groundwater NO 3 from this field for a 6‐ to 10‐yr renovation cycle. Most of the NO 3 loading associated with renovation occurred in Year 2 and was attributed to the manure application. The increased NO 3 loading after renovation likely contributes to the spatial and temporally varying NO 3 patterns observed in the aquifer. Reducing manure applications during renovation and decreasing renovation frequency have the potential to decrease the groundwater NO 3 concentration. Core Ideas We estimated NO 3 flux using vertically high‐resolution groundwater sampling and Darcy flux. Loading was estimated under raspberry field for 6 yr after stand renovation. Renovation frequency is an important control on long‐term NO 3 concentration. An estimated one‐third to one‐quarter of groundwater NO 3 was from renovation in a 6‐ to 10‐yr cycle. Manure was potentially the primary source of additional NO 3 loading during renovation.
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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 | 0.000 | 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 | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.002 | 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".