Productivity and environmental sustainability of grasslands receiving liquid hog manure
Notice bibliographique
Résumé
A two-year (2004 to 2005) experiment was conducted to detemine tlie effect of liquid pratensis) and quackgrass (,4gropyron repens), its effect on forage yield and quality, as well as pasture and animal performance.Environmental sustainability in tenns of nutrient removal and enteric methane (CHq) emissions were also examined.Forage production data was collected from replicated grass hayfields and pastures receiving no liquid hog manure or liquid hog manure as a single application (Full) of 155 kg har of available nitrogen G.Ð in the spring or as a split application (split) of 74kg ha-rof available N in both the spring and the autumn.Multiple 0.25m2 quadrats of standing forage were clipped in hayfields immediately prior to haying to determine DM yield and forage nutrient composition' Quadrat samples were collected in pastures every 2g days to determine DM yield, and hand-plucked forage samples were collected to determine nutrient composition of forage consumed by cattle.As well, pasture productivity, animal production, and enteric CH¿ emissions data were collected.Enteric CH¿ emissiolls were quantified using the sulphur hexafluoride (SFe) tracer gas technique.Animal weight, blood samples and 24-h CHa expiration were measured once in each of thr ee 2g-day periods' Nutrient balance of hayf,relds and pastures was determined by comparing nutrient removal in the form of animal gain or baled hay to nutrients applied in the form of liquid hog manure.Hog manure application on hayfields increased forage yield and nutrient profiles relative to hayfields receiving no fertility.Average standing forage biomass generated in control, SplitandFullhayfieldswere 3.7,g.gandg.4+0.31rha-r,respectivery(p:0.000r).Mean lll standing forage cP was lowest in unmanured standing forage (7.1 + 0.24 yo cp, P:0'0004), while Split and Full hayf,relds had CP concentrations of 9.4 arñ 10.5 yo, in-Spli'lh¿yfi€1ds-(6rc W P:0'0545) than in control or Full hayfields (57.1 and 5s.g %)due to its advanced state of maturity at cutting' Gross energy was highest in manured hayfields (i g.3, l g.6 and I g.5 + 0.06 kJ g-l DM, in control, Sprit and Fuil hayf,rerds, respectively, p:0.0443).Application of hog manure increased nutrient profile of pasture forages relative to those receiving no fertility' Mean forage CP was more than doubled with manure application (P:0'0492).Steers gtazingunmanured pastures had lower serup urea N (2.56 t 0.61 mmol L-l, P:0.0225) values compared to steers grazingmanured pastures (Split :6.06, Full:6'09 mmol L-r¡.Animal DMI and enteric CHa emissions (% GEI) were unaltered by the changes in forage quality as a result of manure application.The addition of hog manure increased pasture carrying capacity over the grazingseason by more than three- fold compared to unmanured pastures, which averaged l0l grazingdays ha-r yr-r.Animal productivity increased from 104 kg gain ha-l for unfenilized to 325 and 344 kg gain ha-l for Split and Full pasture treatments, respectively (p=0.0019).Nitrogen and phosphorus (P) removal efficiencies based on nutrients applied were up to 7-and 4-fold greater in the hayed system compared to the pastoral system, in which only 4.7 % of applied N and 6.r % of the applied p were recovered.The low nutrient utilization effltciencies in each system indicate a need to monitor the rate or frequency of liquid hog manure application to reduce nutrient build-up in the grassland system.IV ACKNOWI,EDGEMENTS I thank Dr. I(im Ominski for hel encouragement and guidance thr.oughout my e-prograffipnd{orpn¡vi with researchers and industry members excited about "my" resealch project.
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 ».