The effect of canola cultivar on water extraction and nitrogen and sulphur uptake
Notice bibliographique
Résumé
The objective of this study was to assess the mechanism that leads to enhanced uptake of N and S by a hybrid canola cultivar. Two canola cultivars, one hybrid (45H21) and one open-pollinated (Conquest) were grown at a single location near Rosebank, MB during the 2003 growing season to study the impact of canola cultivar and S fertilization on the uptake of water, N and S from the soil. The experimental design was a Randomized Complete Block where each cultivar was exposed to three fertilizer treatments: a control, 160 kg N ha-1: 0 kg S ha-1, and 160 kg N ha-1: 27 kg S ha-1. Soil and plant N and S concentrations were measured at midseason and maturity to determine the uptake of N and S by each cultivar. Soil moisture content was monitored throughout the growing season to study the activity of the canola roots. As well, soil cores were removed at midseason to determine the difference in rooting depth by each cultivar. The year following the canola crop experiment, AC Barrie spring wheat was seeded to the canola stubble without N fertilizer to study the effect of N and S uptake by each canola cultivar on a subsequent crop. Biomass was greatest for the hybrid canola cultivar at both sample periods. The concentration of N and S in the canola tissue at midseason was higher in the open-pollinated cultivar, which offset the biomass difference; therefore, the total N and S accumulated by each cultivar was not statistically different. At maturity, the difference in tissue concentrations was seen for S only. The addition of fertilizer caused an increase in biomass proeduction as well as a significant increase in N accumulation at midseason and maturity, and an increase in S accumulation at maturity only. Seed yield was highest for the hybrid cultivar and increased with fertilizer application for both cultivars. There was no interaction between cultivar and fertilizer treatment, indicating that each cultivar responded similarly to fertilizer addition. There was no significant difference in rooting depth between the two cultivars; however, the hybrid cultivar removed 58 mm more water than the open-pollinated cultivar over the 10 to 110 cm soil depth during the growing season, for the N plus S fertilizer treatment only. The difference in root activity may be attributed to the greater biomass of the hybrid canola, leading to higher rates of transpiration. Water use efficiency (WUE) was greater for the hybrid canola cultivar due primarily to the higher seed yield of this cultivar. The biomass accumulated by the wheat seeded onto the open-polliinated canola stubble waas numerically greater than that on the hybrid stubble, but this was significant for the midseason sampling period only. Biomass accumulation and total recovery (biomass and soil) of N and S by the wheat seeded onto the open-pollinated stubble was numerically greater, but not significantly so. Again, there was no interaction between cultivar and fertilizer treatment on either accumulation or recovery of N and S by the wheat crop.
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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 | 0,001 | 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) | 0,002 | 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 ».