The Influence of Peat and Inorganic Amendments on Physical Properties of Sand-Based Rootzones
Notice bibliographique
Résumé
Many golf course putting greens and athletic fields are constructed with a medium consisting of a high sand content. Peat is the most common amendment to rootzone sand (RZS). However, a trend to replace peat with inorganic soil amendments (IOSA), such as calcined clay (CC) and diatomaceous earth (DE), is occurring. Laboratory studies were conducted to evaluate physical and hydraulic properties of rootzone mixtures and a field study investigated the potential of IOSA as a replacement to peat. In laboratory evaluations, amended RZS reduced the bulk density of all mixtures, while saturated hydraulic conductivity (Ksat) for the RZS and mixtures of Canadian sphagnum peat (CSP) and CC exceeded USGA specifications. The DE mixture had the lowest Ksat, which was attributed to the 2% by weight of particles <0.05 mm in diameter. Similarly, RZS water retention and drainage were influenced by amendments. In amended sand mixtures, 0.015 to 0.116 cm3 cm-3 more water was retained compared to unamended sand. Of water retained in the rootzone, the peat mixture held >50% in the upper 15 cm, while straight RZS held the least (37.2%). In drainage experiments, approximately 75% of the total water was lost within the first 15 minutes; however, only 65% was lost in the first 15 minutes for the CSP mixture. After 24 hours of drainage, the CC mixture lost the most water (5.9 cm). Pressure potentials were also measured during drainage. For all mixtures, within 5 minutes of drainage, pressure potentials were negative in the surface 20-cm and positive below the 25-cm depth, indicating saturation. Twenty-four hours after drainage, positive pressure potentials were measured in the gravel layer at the 35-cm depth. In field evaluations of rootzone mixtures on turf grass growth and the rootzone environment, bentgrass (Agrostis palustris Huds. X A. sto/onifera L. 'L-93) seeded into plots amended with peat became established 3 months prior to plots with IOSA and 15 months prior to straight RZS plots. Lower bulk densities were measured in the upper l 0- cm of field cores for amended plots. Also, soil surface strength of peat amended plots were 13 to 31 % lower than RZS and IOSA amended plots. Resistance to penetration in the lower 20 to 30 cm depths ranked in the order of CC> DE> RZS > CSP. The capacitance probe (CP) has been used in mineral soils but not in sand-based, rootzone mixtures to measure soil water content. In laboratory studies, the CP underestimated water content as compared to gravimetric methods; however, linear calibration equations were developed for each mixture. CP readings were unaffected by soil bulk density, but were influenced by amendments. Because of differences between calibration equations for each rootzone mixture, further investigation of the CP is necessary for usefulness as an irrigation tool. Due to greater water retention, lower flow rates, reduced bulk densities, improved turfgrass establishment, and lower impact absorption characteristics, it appears peat remains the best amendment for USGA specification sands.
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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) | 0,001 | 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 ».