Fluctuation in the soil nitrogen supply resulting from green manure plow-down are detected by ion exchange membranes and the nitrogen uptake of arugula (Eruca sativa L.)
Notice bibliographique
Résumé
Green manure crop mixtures contain legumes that capture N2 from the atmosphere. When green manure is plowed down in agricultural soil, the decomposing green manure residues are a source of N fertilizer for the following crop. The challenge is to determine how quickly the green manure releases plant-available N and what proportion of the N requirements of the next crop can be met by green manure. Ion exchange membranes (IEMs) hold promise in evaluating the N supplied by green manure because these in situ measurement tools are placed in the same environment where roots grow, and they act as a sink for plant-available N. The objectives of my thesis were to 1) determine the pattern of plant-available N release from field pea-oat green manure under field conditions with IEMs, and relate this to the N demands of arugula (Eruca sativa L.); 2) to determine if IEMs could detect small changes in plant-available N dynamics in different soil types that were amended with green manure residues having a low C/N ratio; and 3) to determine how tillage practices that reduce the physical size of green manure residues may accelerate plant-available N release from green manure, as determined by IEMs, and meet crop N requirements; 4) to assess the potential contribution of root exudates from arugula on N mineralization after the incorporation of green manure mixture (peas-oats). In a field experiment, in two soil types in Quebec, Canada, a green manure mixture (field pea and oat) contributed to the plant-available N concentration and arugula N uptake. The IEM-NO3-N supply was greater than arugula N demand, suggesting that second crop or a winter cover crop could use the residual soil N released by the green manure. In an incubation experiment, I validated the use of IEMs by incorporating green manure residues with variable C/N ratios. The green manure residues with low C/N ratio (C/N = 8) showed immediate release of plant-available N, whereas residues with C/N = 12 ratio had a delay in releasing plant-available N. The delay suggested that the C/N ratio of green manure residue plus analysis with IEMs was a good indicator of plant-available N dynamics. In addition, the different soil texture (clay loam and sandy loam) modulated the decomposition process and plant-available N concentrations. Greater tillage intensity reduced the percentage of residues with larger particle size. While the higher concentration of plant-available N was released with 4 passes of the cultivator, the maximum N uptake by arugula was reached with 2 passes of the cultivator. Residues remaining after the experiment continued to release plant-available N, suggesting that residual soil N would be left after arugula harvest. The cash crop root exudate demonstrated to play a role in N mineralization through the exudate and showed greater impact on microbial biomass when green manure residues were 0.5 – 1 mm, followed by residues size 2 – 4 mm, and bare soil. In conclusion, the use of IEMs in situ and in incubation experiments could accurately assess the pattern of N release from green manure. This provides insight about the plant-available N dynamics and root input in soils receiving green manure and when N is available for subsequent crops. Farmers can use this information to select crops that will fully use the plant-available N, thus optimizing the N recovery from green manure crops.
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 | 0,000 | 0,000 |
| 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 | 0,000 | 0,000 |
| Science ouverte | 0,000 | 0,000 |
| Intégrité de la recherche | 0,000 | 0,000 |
| Charge utile insuffisante (le modèle a refusé de juger) | 0,000 | 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 ».