Mobility of copper from sulphate and chelate fertilizers in soils
Bibliographic record
Abstract
Copper is a nutrient known for its lack of mobility in soils. This phenomenon affects fertilizer product and placement options when attempting to correct Cu deficiencies. A column experiment was designed to directly compare the mobility of Cu sulphate (CuSO4 5H2O) and a chelated Cu fertilizer (CuEDTA) in five soils with different levels of organic matter (2 to 108 g kg-1 organic C) and clay (4.1 to 34.9%). The movement of Cu, supplied as Cu sulphate and CuEDTA, through a 10- cm column of soil was examined during a 10-d period by monitoring the Cu concentration in leachate following daily additions of 2 cm deionized water and subsequently assaying the soil columns, in 1-cm increments, for DTPA-extractable Cu (DTPACu). Copper sulphate was virtually non-mobile in all soils with at least 20 g kg-1 organic C and 10% clay. However, in a soil with 2 g kg-1 organic C and 4% clay, Cu sulphate moved as much as 7 cm. The restricted mobility of Cu sulphate in all but one soil in this study suggests that in most western Canadian Prairie soils, having relatively high levels of organic matter and clay, Cu supplied as Cu sulphate should be regarded as immobile from an agronomic perspective. In contrast, a portion (2 to 46%) of the CuEDTA moved through the entire 10 cm column of all soils within 3 d, i.e., following three daily additions of 2 cm of water. The enhanced mobility of the chelated Cu is of agronomic significance in that it suggests that this Cu source is more likely to move into the root zone without incorporation and provide adequate feeding sites for a crop when placed in or near the seedrow. Key words: Cu mobility, Cu sulphate, Cu chelate, soil texture, organic matter, leachate
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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 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.001 | 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".