Long-term K fertilization effects on soil available K, grain yield, and plant K critical value in winter wheat
Bibliographic record
Abstract
Abstract This study takes advantage of Swiss long-term field experiments (> 30 yrs) with different K fertilization rates at three sites to (i) test the possibility to generalize linear relationships between K extracts (ammonium acetate, K-AA; ammonium acetate EDTA, K-AAE; water, K-H 2 O; and water saturated with CO 2 , K-CO 2 ), (ii) determine the K fertilization effect on soil exchangeable K, (iii) determine the K fertilization effect on shoot biomass and grain yield of winter wheat, (iv) analyze the possibility to derive a soil K critical value, and (v) determine a critical plant K (K c ) dilution curve as a function of shoot biomass (SB) using a “classical” and a Bayesian method. Shoot biomass during the growing season, grain yield, and four soil extracts were measured in 2018 after more than 30 years with four to five rates of K fertilization. Unpublished data of soil K-AAE concentrations, and grain yield and K concentrations since the start of the experiments were also used to analyze the relationship between soil K-AAE and the cumulative K budget. The K-AA and K-AAE concentrations can be converted from one to the other [K-AAE = 26.8 + (1.11 × K − AA)], while the relationship between K-H 2 O and K-CO 2 depends on soil pH. The K-AAE concentrations were positively related to the cumulative K budget for K-AAE ranges from a minimal K concentration up to a K holding capacity that were specific to each site. The lack of K fertilization during several decades decreased shoot biomass in 2018 and grain yield over the course of the experiments at only one of the three sites. The K-AAE values corresponding to non-limiting soil K conditions at this site (50—75 mg K kg −1 ) were close to the critical values previously reported but the large range suggests that more soil parameters should be taken into account to improve the accuracy of the fertilization guidelines. The Bayesian and “classical” methods used for estimating the K c curve yielded similar results (K c = 58.21 × SB −0.45 ) that should be confirmed in future studies under a range of pedoclimatic conditions along with the effect of other nutrients and wheat cultivars.
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 | 0.000 |
| Science and technology studies | 0.000 | 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".