Nutrient uptake and nitrogen fixation by faba bean in Saskatchewan soils
Bibliographic record
Abstract
As faba bean (Vicia faba L.) production expands in western Canada, limited information is available for modern faba bean cultivars relating to their nutrient requirements and removals, biological nitrogen fixation (BNF), and responses to fertilization. This information is needed to properly manage fertility in cropping rotations containing faba bean. To address this knowledge gap, field studies were conducted at four sites located in the Dark Grey, Black and Dark Brown soil-climatic zones in south-central Saskatchewan in 2016 and 2017. Using four modern zero tannin faba bean cultivars, the effects of two fertilizer treatments on faba bean straw and grain yield, macronutrient (N, P, K, S, Ca, Mg) and micronutrient (Cu, Zn, Fe) concentration and uptake were examined. In addition, a glasshouse experiment was conducted with three P fertilizer rates added to a P deficient soil and two cultivars of faba bean grown, with the above- and belowground yield, N and P concentration and uptake and nitrogen derived from atmosphere (%Ndfa) measured. Soil available nutrients were also measured pre-seeding and post-harvest. The faba bean cultivars demonstrated high yield potential in most site-years, with no significant effect of fertilization or cultivar on yield (~4-6 tonnes ha-1), and average grain N uptake (117-300 kg N ha-1) and grain P uptake (34-82 kg P2O5 ha-1) were generally dependent on soil and environmental conditions experienced according to site location. The N and P uptakes were generally higher compared to uptakes by faba bean and other pulses reported in previous Saskatchewan field studies. Nitrogen accumulated from biological nitrogen fixation (BNF) was about 88 %Ndfa by faba bean, as estimated in the glasshouse study. Given ~230 kg N ha-1 found in aboveground biomass (grain+straw) in the field studies, an estimated ~ 200 kg N ha-1 was potentially contributed from BNF by faba bean. Overall, the high removal of nutrients in faba bean grain observed in this research suggests that fertility management in rotations with faba bean should pay attention to drawdown in the soil over the long-term when faba beans are frequently included in rotation and the grain is harvested.
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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 | 0.001 |
| 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".