Soil enzyme activities following paper sludge addition in a winter cabbage-sweet corn rotation
Bibliographic record
Abstract
Combined primary and secondary papermill sludge (PS) is a good source of C and other nutrients for soils devoted to intensive horticultural production. A field study was conducted to evaluate the effect of PS, spring-applied alone or in combination with ammonium nitrate (AN), on the enzymatic activity of a Bedford clay (Humic Gleysol) in the province of Québec, Canada. The experiment was started in 1996 with winter cabbage (Brassica oleracea var. capitata L.) and continued in 1997 and 1998 on the same plots with sweet corn (Zea mays L.). The PS was applied at 0 (control), 8, 16, 32 and 65 Mg ha −1 in 1996 and at 44% of these rates in 1997. No sludge was applied in 1998. Additional treatments consisted of AN applied yearly at 100% of the plant N requirements and a PS and AN combination. Soil arylsulfatase and acid and alkaline phosphatase activities were measured at three different times in each growing season. The PS rate linearly increased the soil acid phosphatase activity in all 3 yr. In contrast, the alkaline phosphatase and arylsulfatase activities were enhanced in 1997 by the 8–16 Mg PS ha −1 treatments, whereas larger amounts of PS showed activity comparable to the control. The second PS application promoted phosphatase activities mostly in fall, but did not sustain arylsulfatase activity. The AN gave lower phosphatase activities than PS, and depressed arylsulfatase. Addition of AN to PS increased only acid phosphatase activity as compared with PS alone or the control. This study indicated that addition of PS improved enzyme activity of this horticultural soil but rates in excess to 32 Mg ha −1 may be detrimental. Key words: Papermill sludge, soil enzyme, cabbage, corn
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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 | 0.000 |
| Scholarly communication | 0.000 | 0.002 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.004 | 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".