Understanding the Impacts of Crop Rotation on Soil Microbial Dynamics and Carbon Cycling
Notice bibliographique
Résumé
Soil organic matter (SOM) is the largest terrestrial C sink on the planet and plays a key role in C storage. The quantity and forms of SOM storage in agricultural soils are an indicator of soil health, function, and fertility in cropping systems. Canola, wheat, and corn, considered staple cash crops across Canada, have recently been grown with increasing frequency within crop rotations. However, little is known about the impact of short rotation cropping systems on SOM and the formation of different SOM functional pools. The objective of this research was to assess crop frequency impacts on microbial communities through measurement of phospholipid fatty acids (PLFA), on enzyme activities, and on soil C storage in particulate organic matter (POM) and mineral-associated organic matter (MAOM) functional pools. Soil samples were collected from long-term AAFC rotational studies including a multi-site canola frequency study (est. in 2008), a continuous wheat vs. rotation wheat study at Swift Current, SK (est. 1987), and a continuous vs. rotation corn study at Harrow, ON (est. 2001). For all soils, we measured total C and organic C content of physically fractionated POM and MAOM and PLFA. Beta-glucosidase (BG), N-acetyl-glucosaminidase (NAG), phosphatase (PHOS), phenol oxidase (PHN.OX), and arylsulfatase (ARYL) enzyme assays were performed on the canola rotation study while the cereal rotation samples were assayed for ß-D-cellobiohydrolase (CBH), ß-Xylosidase (BX), and PHN.OX activity. Canola and corn grown continuously vs. in rotation had inconsistent impacts on microbial community composition and appeared to respond more strongly to the time of sample collection than crop rotation. Extracellular enzyme activity was impacted greatest by location, sampling time, and crop growth stage rather than crop rotation. There were no differences found in soil organic C (SOC) storage in either POM or MAOM C pools in response to long-term crop rotation practices indicating that although continuous monocropping is not recommended as a best practice agronomically, it does not impact the quantity of C stored in the functionally-relevant pools. The amount and proportion of MAOM C (mg C g-1 soil) was consistently greater than POM C content across all crop rotation systems and field sites. From these results we determined the dominant driving factors to microbial dynamics and SOC storage in our studies were soil moisture and edaphic soil properties, as moisture levels are key determinants of microbial activity, community dynamics and SOM turn over. Although these experiments had been ongoing for many years, the studies analyzed in this work may not be long enough in length to assess changes in SOM C storage in agricultural soils. While changes in SOM have been observed over time in response to land management practices, these changes are slow and gradual. In our studies the change implemented was one management factor, rotation, where the length of time our observations occurred over may not be long enough for the rotational practices tested in our studies to impact SOM C storage.
Récupéré en direct depuis OpenAlex et désinversé. Les résumés ne sont pas conservés dans cette base de données : les index inversés représentent 8,6 Go des 9,3 Go de texte de la base, et le serveur dispose de 13 Go libres.
Comment cette classification a été obtenuedéplier
Prédiction machine sur la base complète
Imitation des enseignantsNi prévalence calibrée, ni vérité terrain. Validation humaine à venir. Le volet Gemma est une étiquette directe du modèle pour chaque travail de la base, lue sur la notice réduite au titre. Le volet Codex est un classifieur appris des 10 348 étiquettes directes de Codex et calibré sur les taux pondérés de l'échantillon; les champs sans appui suffisant ne portent aucun appel Codex. Le mode candidate est l'union des deux volets; le consensus est leur intersection. Ces sorties portent le statut machine_predicted_unvalidated et ne sont pas des étiquettes humaines.
Scores du classifieur distillé par catégorie (deux têtes)
| Catégorie | Codex | Gemma |
|---|---|---|
| Métarecherche | 0,001 | 0,001 |
| Méta-épidémiologie (sens strict) | 0,000 | 0,000 |
| Méta-épidémiologie (sens large) | 0,000 | 0,000 |
| Bibliométrie | 0,000 | 0,000 |
| Études des sciences et des technologies | 0,000 | 0,000 |
| Communication savante | 0,001 | 0,001 |
| Science ouverte | 0,000 | 0,000 |
| Intégrité de la recherche | 0,000 | 0,000 |
| Charge utile insuffisante (le modèle a refusé de juger) | 0,001 | 0,000 |
Scores machine (provisoires)
Les deux têtes enseignantes du modèle étudiant, lues sur ce travail. Un score ordonne la base pour la relecture; il n'affirme jamais une catégorie, et le statut de validation accompagne chaque rangée tel quel.
Scores de référence d'un modèle non mature (critères de maturité non atteints, 7 itérations). Un score ordonne; il n'affirme jamais une catégorie.
score_only:v0-immature-baseline · tel quel depuis la passe de notation : score_only signifie que le nombre peut ordonner les travaux, et qu'aucune étiquette de catégorie n'en découleClassification
machine, non validéePrédiction automatique; un appel candidat d’une seule source (Gemma direct ou Codex distillé), pas un consensus.
Le détail, modèle par modèle et score par score, se trouve en fin de page sous « Comment cette classification a été obtenue ».