MYCORRHIZAE IN MAIZE (<i>Zea mays</i> L.) CROPPING SYSTEMS RESPOND DIFFERENTLY TO NITROGEN FERTILIZATION UNDER INCREASING CROP ROTATIONAL DIVERSITY
Bibliographic record
Abstract
Arbuscular mycorrhizal fungi (AMF) remain a vital obligate symbiont of nearly all plants. It is well established that the symbiosis between AMF and host plant improves plant nutrient acquisition, alleviates abiotic and biotic environmental stressors, defends against plant pathogens, and contributes to overall plant fitness and productivity through modification of the soil habitat. Modifications include increased soil aggregation and stability, carbon sequestration through provision of fungal wall precursors to soil organic matter (SOM) formation, and enhanced nutrient cycling in the mycorrhizosphere. The goal of this dissertation was to assess how AMF respond to nitrogen (N) fertilization regimes in maize cropping systems of increasing crop rotational diversity. Two, long-term field sites were used to evaluate AMF responses to N application during maize growth. The first site was a conventionally tilled and rainfed site in Elora, Ontario, Canada at the University of Guelph, hereafter referred to as Canadian Nitrogen Study (CNS). CNS evaluates contrasting mineral fertilization rates applied either continuously for 10 years or shocked with a higher/lower N rate once every five years. We demonstrate that soil AMF biomass is more responsive to current season N application rates than historical N regimes and supports our prior research showing that extramatrical AMF biomass declines with increasing N applied. The second site is a rainfed, no-till maize system managed by the United States Department of Agriculture (USDA) and referred to as Crop Rotation Study (CRS). CRS was sampled seasonally over two years for soil biological and chemical properties and was designed to evaluate soil C and N stocks in diverse rotations with continuous corn under three levels of N fertilization. We found a similar inverse relationship of extramatrical AMF to N application rate as in CNS and demonstrate how N fertilization drove AMF biomass dynamics in the soil. Due to the agronomic importance of maize, it is necessary to cultivate sustainable management practices that contribute to resilient mycorrhizal communities and SOC stabilization. Advisor: Rhae A. Drijber
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
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 | 0.000 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| 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 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".