Potassium adsorption characteristics and potassium forms in some New South Wales soils in relation to early senescence in cotton
Notice bibliographique
Résumé
The occurrence of premature senescence (PS) in cotton in Australia has been related to decreased potassium (K) concentration in the affected plants. Soil samples (0–120 cm) were taken from paired cotton fields, i.e. PS fields and similar soils not affected by PS (Non-PS fields), in northern New South Wales. The samples were analysed for different forms of K in soil, mineralogy of various size fractions, and K adsorption characteristics to evaluate differences in their K availability. Smectite was the dominant clay mineral in the studied soils. The K-bearing mineral illite was present in the clay fraction of all samples and its content was generally higher in soils from the Non-PS sites than the PS sites from Moree, Pilliga, and Warren. Water-soluble K (H2O-K) ranged from 0.03 to 2.64 mg/kg (median 0.35 mg/kg), exchangeable K (Exch-K) from 43 to 687 mg/kg (median 107 mg/kg), non-exchangeable K (Nonexch-K) from 164 to 1981 mg/kg (median 819 mg/kg), and total K (Total-K) from 16 811 to 23 207 mg/kg (median 14 740 mg/kg). The values of various K forms were generally higher in samples from the Non-PS fields than the PS fields from Pilliga and Warren sites and the reverse trend occurred for the samples from Trangie. Similar H2O-K and Exch-K values were found for the PS and Non-PS samples from Moree, whereas Nonexch-K and Total-K contents were higher in the top 60 cm soil depth from the Non-PS field than the PS field. The equilibrium activity ratio (ARKe) values were significantly higher for surface samples from the Non-PS sites than the PS sites from Pilliga and Warren and the reverse was true for the Trangie site. There was a sharp decrease in ARKe with depth for the studied samples. The potential buffering capacity (PBCK) for both surface and subsurface samples from the Non-PS site (mean 31.5 (mmol/kg)/(mol/L)1/2) from Trangie was substantially higher than the corresponding samples from the PS sites (mean 14.7 (mmol/kg)/(mol/L)1/2). There was a significant increase in K adsorption for the subsurface samples than the surface samples for all sites, as indicated by the higher values of Freundlich adsorption coefficient, k. At the Pilliga and Warren sites, the occurrence of premature senescence in cotton plants can be explained on the basis of differences in the levels of different forms of K, mineralogy, and K adsorption characteristics of soils from the PS and Non-PS fields. At the Moree site, higher illite content in the Non-PS than the PS soil may explain the difference in their K availability. For the paired Trangie samples, greater PBCK of the Non-PS soil than the PS soil may be responsible for increased K availability in the Non-PS soil. The occurrence of PS symptoms in cotton at Narrabri site cannot be directly contributed to K supplying parameters analysed in the study. The results also show that Exch-K alone may not be adequate to measure K availability to cotton in these soils.
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 | 0,001 | 0,001 |
| Études des sciences et des technologies | 0,001 | 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) | 0,001 | 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 ».