Nitrogen partitioning, content and efficiency in hybrid canola
Bibliographic record
Abstract
Canola is a valuable oilseed crop worldwide and in Canada. More than half of Canada’s canola is produced in Saskatchewan every year. Farmers use nitrogen fertilizer supply so that canola crops reach their yield potential. Canola, like corn, is a crop that is know for high nitrogen fertilization requirements. A two year study was conducted at three locations across Saskatchewan with the main goal of establishing and characterizing in-plant nitrogen uptake and distribution in canola plants under a range of nitrogen fertilizer rates (0 to 200 kg ha-1) and two application methods, single banding beside the seed and a split broadcast fertilizer application. Two modern canola cultivars were sampled from the onset of flowering until their final harvest from plots arranged in a randomized complete block design at Melfort and Scott in 2019, and at Saskatoon in 2020. Canola two-plant subsamples were divided into their plant parts (stem, leaf, pods), which were measured for length and area, then oven-dried. They were then weighed, ground, and analyzed for tissue nitrogen concentration by combustion. Canola plants showed an overall positive response to an increasing rate of nitrogen fertilizers for both mass of tissue and tissue nitrogen concentrations, and in total yield. Nitrogen concentration in tissues were significantly higher in plants grown with higher nitrogen fertilization rates. The different nitrogen fertilizer treatments had little effect on the plant partition composition or the proportion of nitrogen distribution within plant organs. Overall, the modern canola crop used most of the provided nitrogen and placed it in seed yield regardless of the fertilizer rate, with plants placing about 75% of the total plant shoot nitrogen into seed yield. The seed yield constituted about 40% of the plant dry biomass and the rest of the biomass was evenly split between the dry stem and the pod walls. Results of this study indicated that canola in Saskatchewan is efficient in using provided nitrogen to produce yield. Nitrogen use efficiency of applied fertilizer, however, was more variable and differed among the locations due to management differences, soil types, and seasonal rainfall. Nitrogen use efficiency was best assessed using nitrogen harvest index and nitrogen utilization efficiency for a full-season yield-focused metric, while nitrogen uptake efficiency was best suited for initial extraction and uptake of fertilizer to total plant biomass by flowering.
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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 | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.001 |
| 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".