Arbuscular mycorrhizae and the phosphorus nutrition of maize: A review of Guelph studies
Bibliographic record
Abstract
The role of mycorrhizae in phosphorus nutrition of maize (Zea mays L.) is related to the fact that the P concentration in maize shoots at the four- to five-leaf stage affects final grain yield.In the early 1980s we observed greater early-season shoot-P concentration (mg g−1) and P absorption (mg plant−1) from a no-till compared to a conventional tillage system. Further studies established that the greater P absorption is due to a more effective arbuscular mycorrhizal (AM) symbiosis when the soil is not disturbed. The greater P absorption is largely a result of the undisrupted mycelium present in an undisturbed soil, rather than to increased colonization. This mycelium retains viability through extended periods in frozen soil. In the spring this mycelia network is able to acquire P from the soil and deliver it to the plant immediately upon becoming connected to a newly developing root system. Increased P absorption has not resulted in increased grain yield in field trials. Some additional factor limits yield with no-till maize preventing the advantage of early P absorption from being realized as yield. When maize follows a non-mycorrhizal crop such as canola (Brassica napus L.), mycorrhizal colonization is delayed, reducing early-season P absorption. Yield reductions may occur.In summary, AM mycorrhizae are involved in P nutrition of maize and an understanding of their functioning will assist us in modifying management practices to maximize economic returns through increased fertilizer efficiency. Key words: Maize, arbuscular mycorrhizae, phosphorus nutrition, tillage, canola
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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) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.004 | 0.004 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.002 | 0.001 |
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".