Controlled-release P fertilizer concept evaluation using growth and P uptake of barley from three soils in greenhouse
Bibliographic record
Abstract
Use of controlled-release P fertilizers to match the fertilizer P availability to crop requirement has potential for improvement of P uptake and crop production. Greenhouse experiments were conducted to evaluate the concept of controlled-release P fertilizer by using different coatings to regulate the release of P and to compare the growth and P uptake of barley (Hordeum vulgare L.) in three Alberta soils. Testing of different coatings in one experiment was followed by further evaluation of the promising treatments in two experiments. Commercial monoammonium phosphate (MAP) and diammonium phosphate (DAP) were coated with a polymer (thin-coated, 1.8% by weight or thick-coated, 2.2%) or enveloped in commercial packaging polyethylene film (shrink wrap, SW) with two, four or six pin-holes to control P release. Thin-coated treatment showed greater dry matter yield (DMY), P uptake (PU), net fertilizer P efficiency (NFPE) and net fertilizer releases efficiency of MAP compared to the uncoated, thick-coated or SW treatments in many cases. Coating of DAP did not consistently improve any of the above-mentioned parameters. In some cases, uncoated fertilizer had greater DMY, PU and NFPE than the polymer-coated treatments in early stages of crop growth (at the 13th, 26th, and 30th days), but coated treatments generally performed better during later stages of crop (at the 39th, 45th, 60th and 90th days). At 31.4 mg P pot -1 for example, thick-coated treatment had about 25% of its total PU during the 60th to 90th day, which resulted in greater spike yield accumulation in this treatment (8.4 g pot -1 ) compared to uncoated fertilizer (5.0 g pot -1 ). The P release rate was greater with thin-coated fertilizer than with thick-coated fertilizer during the 0 to 13th days (by 0.199 mg P kg -1 d -1 ) and the 13th to 26th days (by 0.084 mg P kg -1 d -1 ), but the opposite was true during the 26th to 39th days (by 0.112 mg P kg -1 d -1 ) and the 39th to 52th days (by 0.064 mg P kg -1 d -1 ). The polymer-coated, in particular the thin-coated, fertilizers delivered P in a manner that allowed the plants to use it more effectively than the uncoated MAP in several cases, which indicated a potential for improvement of fertilizer P efficiency and crop production. Key words: Barley growth, controlled-release P fertilizer, P uptake, yield
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 | 0.001 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.001 |
| Science and technology studies | 0.000 | 0.001 |
| 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".