Effect of Topdressed Controlled-release Fertilizer Rates on Nursery Crop Quality and Growth and Growing Substrate Nutrient Status in the Niagara Region, Ontario, Canada
Bibliographic record
Abstract
The objectives of the current study were to 1) determine the best topdressed controlled-release fertilizer (CRF) application rates for quality and growth of two nursery crops under temperate climate outdoor nursery production conditions in the Niagara region, Ontario, Canada, and 2) evaluate the nutrient status of the growing substrate following topdressing of two CRF types during the growing season. Fall-transplanted Goldmound spirea ( Spiraea × bumalda ‘Goldmound’) and Wine & Roses ® weigela [ Weigela florida (Bunge) A. DC. ‘Alexandra’] were grown in 2-gal (7.56 L) containers and topdressed on 7 May 2015 with Osmocote Plus 15N–3.9P–9.9K, 5–6 month CRF or Plantacote 14N–3.9P–12.5K, 6 month Homogeneous NPK with Micros. CRF was applied at rates of 1.5, 3.0, 4.5, 6.0, 7.5, and 9.0 g nitrogen (N)/pot for both species. The best plants at the end of the growing season (i.e., 23 Sept. 2015) were spirea at 3.0–4.5 and 3.0–6.0 g N/pot, and weigela at 3.0–4.5 and 6.0 g N/pot, with Osmocote and Plantacote, respectively. At CRF rates above these rates, the majority of plants showed no increase in growth or quality attributes. All weigela plants, despite CRF application rate, showed K deficiency symptoms during the study. Using marketable-size criteria and plant growth data over time, estimates of production timing are presented for fall-transplanted, spring-topdressed weigela and spirea. These estimates may assist growers in choosing CRF application rates to meet time-sensitive production goals. Early in the growing season, NO 3 -N and P concentrations in the growing substrate were highest at CRF rates ≥4.5 and ≥6.0 g N/pot, respectively, and P continued to be high in August and September at 9.0 g N/pot. NH 3 -N and K concentrations at all CRF application rates were greater early in the growing season and decreased over time. At high CRF rates toward the end of the growing season, concentrations of NO 3 -N, NH 3 -N, and P once again increased. Considering crop-specific CRF application rates and understanding changes in growing substrate nutrient status during the growing season may help nursery growers prevent negative environmental impacts from over-fertilizing.
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 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 | 0.000 | 0.000 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.000 | 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 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".