Potential influence of poorly crystalline minerals on soil chemistry in <scp>P</scp> odzols of southwestern <scp>C</scp> anada
Bibliographic record
Abstract
Summary Concepts of soil chemistry were established, in the main, for agricultural soils with a fine texture and near‐neutral pH . These concepts often need to be modified when considering acidic forest soils. For example, studies conducted in northeastern US forests challenged the idea of a universal positive relationship between base saturation ( Bsat ), effective cation exchange capacity ( CEC e ) and pH . The objective of this study was to measure soil chemistry variables in P odzols of southwestern C anada and determine their interrelationships as well as the potential influence of surface‐active iron ( Fe ) and aluminium ( Al ) species. We measured exchangeable cation concentration in each pedogenic horizon and investigated their relation to pH , soil organic carbon, silt and clay and pyrophosphate‐extractable, oxalate‐extractable and dithionite‐extractable Al and Fe . We found that the chemistry of the forest floor was different from that of the mineral soil because of the limited extent of mixing between the two layers. In the forest floor, biological cycling maintained a large Bsat and large calcium saturation but a low pH . In the subsoil, pH had a positive correlation with Bsat but a negative correlation with CEC e . The formation of organo‐mineral complexes between soil organic matter and short‐range order Al and Fe phases could explain the anomalous relationship between pH and CEC e . This study provides new insight into mechanisms controlling forest soil chemical properties and should hence contribute to our ability to manage forests for long‐term productivity. Résumé Les concepts de la chimie du sol ont été développés pour la plupart dans des sols agricoles de texture fine et pH proche de la neutralité. Ces concepts doivent souvent être modifiés lorsque les sols forestiers acides sont considérés. Par exemple, des études conduites dans les forêts du nord‐est des Etats‐Unis ont remis en question le caractère universel de la corrélation positive entre le taux de saturation (Bsat), la capacité d'échange cationique effective (CECe) et le pH. L'objectif de ce travail était de mesurer les paramètres courants de la chimie du sol dans des podzols du sud‐ouest canadien afin d'établir leur interrelation ainsi que l'influence potentielle des espèces minérales réactives de fer (Fe) et d'aluminium (Al). A ces fins, nous avons mesuré la concentration de cations échangeables dans chaque horizon pédogénétique et avons étudié sa relation avec le pH, le carbone organique du sol, les limons et argiles, et le Fe et Al extraits par le pyrophosphate, l'oxalate et le citrate‐bicarbonate‐dithionite. Les résultats montrent que la composition chimique de l'horizon organique est très différente par rapport au sol minéral. Ceci s'explique par le faible taux de transfert entre les deux couches. Dans l'horizon organique, le phénomène de recyclage biologique maintient une forte Bsat et forte saturation en calcium, mais un pH faible. Dans les horizons du sous‐sol, le pH est corrélé de manière positive avec la Bsat mais de manière négative avec la CECe. La formation de complexes organo‐minéraux entre la matière organique du sol et les minéraux de Fe et Al mal cristallisés pourraient être á l'origine de la relation surprenante entre le pH et la CECe. Cette étude fournit de nouveaux éléments quand aux mécanismes régissant les propriétés chimiques des sols forestiers et devrait ainsi contribuer á améliorer notre capacité de gestion de la forêt pour une productivité durable.
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 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 | 0.001 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 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".