The Changing Characteristics of Profile Distribution of Soil Organic Nitrogen Component of the Typical Soil Types on the Loess Plateau
Bibliographic record
Abstract
【Objective】 In order to evaluate the effects of location,soil depth and land use on the contents of soil organic nitrogen(N),the size and composition of soil organic N pool were studied using a large variety of soil profiles sampled on the Loess Plateau.【Method】 Based on different soil types and land-use patterns,96 soil samples in 8 depth classes(0-10,10-20,20-40,40-60,60-80,80-100,100-120 and 120-140 cm)were collected from different regions on the Loess Plateau.The method of Bremner was used to test the soil organic N content.【Result】Even with the same land use pattern,the content of soil depth-specific total soil hydrolysable N and its components increased from north to south on the Loess Plateau.The proportion of organic N components within total hydrolysable N was stable.However,the proportion of total hydrolysable N in total soil N significantly decreased within 0-40 cm layers and remained stable below 40 cm.The content of four components significantly decreased within 0-40 cm,slightly decreased within 40-80 cm and remained stable below 80 cm.The percentage of organic N components in total hydrolysable N differed among soil types: amino acid-N(39.5%)ammonia N(32.3%)HUN fraction(25.7%)amino sugar-N(2.5%) in Ust-Sandiic Entisols;amino acid-N(36.0%)ammonia N(35.6%)HUN fraction(25.3%)amino sugar-N(3.1%) in Los-Orthic-Entisol;and ammonia N(50.6%)amino acid-N(29.0%)HUN fraction(17.5%)amino sugar-N(2.8%) in Eum-Orthic Anthrosol.Except amino sugar-N,all the soil organic N components within 0-40 cm in grassland were more than those in cropland;however,the inter-layer variation became smaller with the profiles.【Conclusion】From north to south of the Loess Plateau,the content of organic N and its different forms increased,the proportion of organic N component in total hydrolysable N was stable in the same layer under the same land-use patterns.However,the proportion of total hydrolysable N in total soil N decreased.Amino acid-N and ammonia N were the major forms of the soil organic N on the Loess Plateau.Land-use pattern had a great effect on the content and distribution of N.Both organic N and its components in grassland was more than that in cropland.
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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) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 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 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".