Soil and crop responses to long-term potato production at a benchmark site in northwestern New Brunswick
Bibliographic record
Abstract
Concerns about deteriorating soil quality led to Agriculture and Agri-Food Canada establishing a network of 23 soil quality monitoring benchmark sites with the objective of providing a baseline data set for assessing change in soil quality and biological productivity of representative Canadian farming systems. A site (22-NB) was established in 1990 in northwestern New Brunswick to monitor changes in Podzolic and Brunisolic soils developed on coarse loamy till on a rolling landscape under intensive potato (Solanum tuberosum L.) production [potato-potato-barley (Hordeum vulgare L.) rotation] that was cultivated along the contour with variable grade diversions and a grassed waterway. Soil samples were collected in 1990 and again in 2000. Field saturated hydraulic conductivity (Kfs) at 10–20, 26–36 and 50–60 cm, earthworm counts and crop yield measurements were conducted annually. 137Cs data were collected in 1990 to estimate soil displacement at the site. Runoff and soil loss between May 01 and Nov. 30 were measured annually. The soil conservation system at site 22-NB has resulted in annual runoff and soil loss of only 9 mm and 311 kg ha-1, respectively. Measured values of 137Cs averaged 2114 Bq m-2 (70% of baseline). Changes in the Ap horizon properties between 1990 and 2000 included significant (P < 0.05) increases in available P (+ 86.7 mg kg-1) and K (+ 13.4 mg kg-1) and significant reductions in available Mg (−45.8 mg kg-1) and SOC (−0.51 g kg-1). The Kfs of 10- to 20-cm, 26- to 36-cm and 50- to 60-cm depths were 1.3, 1.0 and 1.0 cm h-1, respectively. Very few earthworms were present (0.05 worms m-2). The upper terrace was consistently the highest yielding in both potato and barley, while the lowest terrace was consistently the lowest yielding in both crops. Crop yields may have been affected by micro-climate and other soil differences as a result of site position.While the system of contour tillage with variable grade diversions and grassed waterway conserved both soil and water, the potato-potato-grain rotation did not maintain SOC levels or sustain earthworm populations. Associated heavy rates of fertilization also lead to increased levels of soil K and P. Key words: Soil quality, soil organic carbon, hydraulic conductivity, earthworms, runoff, water erosion
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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 | 0.001 | 0.001 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.001 | 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".