Dry-matter production and botanical composition of multispecies and perennial ryegrass swards under varying defoliation management     

Shona Baker  Mary B. Lynch  Fionnuala Godwin  Eugene Brennan  Tommy M. Boland  Alexander C. O. Evans  Alan K. Kelly  Helen Sheridan 《Grass and Forage Science》2023,78(3):390-401

Multispecies swards, comprised of different plant functional groups have comparable production potential to high N input L. perenne swards at reduced N when legumes are included. However, information on the appropriate management of multispecies swards is limited. The effect of differing management practices on the herbage dry-matter (DM) production and botanical composition of different sward types was investigated using a 3 × 2 × 2 factorial design plot experiment. The experiment consisted of three sward types: L. perenne-only receiving (LP; 250 kg N ha⁻¹ a⁻¹); L. perenne-Trifolium repens (LP-TR); multispecies sward containing L. perenne, Phleum pratense, Trifolium repens, Trifolium pratense, Plantago lanceolata and Cichorium intybus (MSS). LP-TR and MSS received 90 kg N ha⁻¹ a⁻¹. Harvesting of plot herbage took place every 21 or 28 days to a defoliation height of 4 or 6 cm, over two growing seasons (March to November 2020 and 2021 inclusive). Annual herbage produced by both LP and LP-TR was not significantly affected by defoliation frequency. However, MSS produced 1923 kg DM ha⁻¹ a⁻¹ more herbage when harvested less frequently. Unsown species contributed significantly less to the herbage DM of MSS compared to LP and LP-TR and remained similar in 2020 and 2021, whereas the contribution of unsown species to herbage DM increased in LP and LP-TR from 2020 to 2021, with noxious species more associated with LP and LP-TR than MSS. Results demonstrate the role of multispecies swards in improving the sustainability of grass-based agricultural systems in an environment of reduced fertilizer inputs.  相似文献   

Innovative developments for long‐term mammalian pest control     

Helen M Blackie  Jamie W.B MacKay  Will J Allen  Des H. V Smith  Brent Barrett  Belinda I Whyte  Elaine C Murphy  James Ross  Lee Shapiro  Shaun Ogilvie  Shona Sam  Duncan MacMorran  Shane Inder  Charles T Eason 《Pest management science》2014,70(3):345-351

  相似文献   

Polygenetic development of the Mormon Mesa,NV petrocalcic horizons: Geomorphic and paleoenvironmental interpretations     

Amy L. Brock  Brenda J. Buck 《CATENA》2009

Mormon Mesa, Nevada, USA is of one of Earth's rare and unique landforms. Regionally, Mormon Mesa is important because of its relationship to the lower Colorado River and its connection to stream incision. Petrocalcic horizons at Mormon Mesa developed from multiple exposure, erosion, and sedimentation events driven by variations in paleoclimate since the early Pliocene. This study utilizes pedogenic features at Mormon Mesa to construct a sequence of development for the soil profile. We sampled and described seven profiles at Mormon Mesa to determine the soil and geomorphic processes that have influenced the development of this geomorphically important soil. The Mormon Mesa soil profile generally consists of four petrocalcic soil horizons from the base upward (transitional, laminar, massive, and brecciated) and an additional set of horizons that formed in unconsolidated surficial eolian sediments. The transitional horizon formed after cessation of Muddy Creek Fm. deposition (~ 5 to 4 Ma) and accumulated calcium carbonate to a stage II–III morphology (maybe IV in some locations). After a period of landform stability, the upper portion of the transitional horizon was exposed and eroded (~ 2.8 Ma). Petrocalcic fragments and stage II pendants that formed in the transitional horizon were exposed on the surface and later mixed with aggrading eolian sediments. After the surface re-stabilized, calcium carbonate accumulated along the underlying discontinuity with the transitional horizon and formed a laminar horizon. Shallower accumulations of calcium carbonate formed pendants on the undersides of the rotated petrocalcic fragments and pendants that had previously been eroded from the transitional horizon. Continued rooting and bioturbation caused rotation and multiple directions of pendant formation. Today, in plan view, these pendants appear concentric and are the pisoliths described by Bachman and Machette [Bachman, G.O., Machette, M.N., 1977. Calcic Soils and Calcretes in the Southwestern United States., USGS: Open-File Report 77–797]. Continued calcium carbonate precipitation eventually plugged the horizon (massive horizon). After the massive horizon became indurated, the upper portion was exposed, fractured, eroded, and mixed with aggrading eolian sediments. These brecciated fragments experienced erosion/brecciation and soil stabilization/cementation with pedogenic calcite multiple times, probably as a result of the Pleistocene glacial/interglacial climate cycles. All of the features described in this study are interpreted to have formed in response to climatic changes that caused either soil erosion with concurrent eolian deposition, or soil development and pedogenic carbonate accumulation.  相似文献   

Ruptured capsule of the elbow joint of a draught horse     

L. Livesey  J. Schumacher  E. Sartin  M. Caldwell  S. Ziska  K. Brock 《Equine Veterinary Education》2009,21(7):371-374

A cyst filled with fluid was found to be the cause of an enlarged antebrachium in a horse. Communication between the cyst and the elbow joint was demonstrated by: 1) finding, during radiographic examination of the elbow, radiopaque contrast solution instilled into elbow joint within the cyst; 2) finding cytological values in fluid aspirated from the cyst that were similar to those in fluid aspirated from the elbow joint; and 3) finding hyperechoic foci, assumed to be air bubbles, during ultrasonographic examination of the cyst after administration of air into the elbow joint. Communication of the cyst with the elbow joint was confirmed during post mortem examination of the affected limb.  相似文献   

Comparative growth performance of pigs immunised with a gonadotrophin releasing factor vaccine with surgically castrated pigs and entire boars raised under conventionally managed conditions     

Fuchs T  Nathues H  Koehrmann A  Andrews S  Brock F  Klein G  Beilage Eg 《Berliner und Münchener tier?rztliche Wochenschrift》2011,124(1-2):22-27

The objective of this study was to determine the effect of using a gonadotrophin releasing factor (GnRF) vaccine on growth performance of male pigs. Vaccinated pigs were compared with surgically castrated pigs and entire males under conventionally managed farm conditions. Male pigs were randomly assigned to three treatment groups: pigs surgically castrated during the first week of life (group "C", n=274), pigs immunised twice during the fattening period with a GnRF vaccine, the first when 13-14 weeks of age and the second when 20-21 weeks of age (group "V" n=280) and entire males (group "E", n=56). Average daily weight gain (ADG) was measured during the study. Additionally, feed conversion ratio (FCR) as defined by feed intake/weight gain and feed consumption was assessed during the fattening period. No difference in the ADG during the fattening period could be determined between "C" and "V". From the start of the study until slaughter at study day 160/173 the ADG in group "E" was lower (625 g/day; P) than in group "C" (681 g/day; P < 0.001) and group "V" (675 g/day; P < 0.01). The FCR during the fattening period until study day 160, three days before the first batch of pigs were slaughtered at 24-25 weeks of age, was higher in group"C" (2.72 kg feed intake/kg weight gain) compared with group "V" (2.44 kg feed intake/kg weight gain; P < 0.001) and group "E" (2.44 kg feed intake/kg weight gain; P <0.01). Pigs in group "V" performed similarly to those in group "E" until the second vaccination (day 135) after which time they showed a substantial increase in feed intake and ADG, while retaining an FCR advantage over group C.  相似文献   

Norsesquiterpene glycosides in bracken ferns (Pteridium esculentum and Pteridium aquilinum subsp. wightianum) from Eastern Australia: reassessed poisoning risk to animals     

Fletcher MT  Brock IJ  Reichmann KG  McKenzie RA  Blaney BJ 《Journal of agricultural and food chemistry》2011,59(9):5133-5138

Austral bracken Pteridium esculentum contains three unstable norsesquiterpene glycosides: ptaquiloside, ptesculentoside, and caudatoside, in variable proportions. The concentration of each of the glycosides was determined in this study as their respective degradation products, pterosin B, pterosin G and pterosin A, by HPLC-UV analysis. Samples of P. esculentum collected from six sites in eastern Australia contained up to 17 mg of total glycoside/g DW, with both ptaquiloside and ptesculentoside present as major components accompanied by smaller amounts of caudatoside. Ratios of ptaquiloside to ptesculentoside varied from 1:3 to 4:3, but in all Australian samples ptesculentoside was a significant component. This profile differed substantially from that of P. esculentum from New Zealand, which contained only small amounts of both ptesculentoside and caudatoside, with ptaquiloside as the dominant component. A similar profile with ptaquiloside as the dominant glycoside was obtained for Pteridium aquilinum subsp. wightianum (previously P. revolutum ) from northern Queensland and also P. aquilinum from European sources. Ptesculentoside has chemical reactivity similar to that of ptaquiloside and presumably biological activity similar to that of this potent carcinogen. The presence of this additional reactive glycoside in Australian P. esculentum implies greater toxicity for consuming animals than previously estimated from ptaquiloside content alone.  相似文献   

Ecology. The world through a bat's ear     

Fenton MB 《Science (New York, N.Y.)》2011,333(6042):528-529

  相似文献   

Development of soil organic matter stocks under different farm types and tillage systems in the Organic Arable Farming Experiment Gladbacherhof     

Franz Schulz  Christopher Brock  Harald Schmidt  Klaus-Peter Franz 《Archives of Agronomy and Soil Science》2013,59(3):313-326

In 1998, the Organic Arable Farming Experiment Gladbacherhof (OAFEG) was started in order to explore the impact of different organic arable production systems (mixed farming, stockless farming with rotational ley, stockless cash crop farming) and of different tillage intensities (conventional plough as a full inversion tillage, two-layer plough, inversion tillage at reduced depth, non-inversion tillage) on sustainability parameters. In this article, we present results on the development of soil organic matter (SOM) levels. Starting with organic mixed farming with approximately 0.7 livestock units (LU) per ha cattle before set-up of the experiment, only the mixed farming system in the experiment was able to maintain SOM levels. The stockless system with ley maintained soil organic carbon (SOC), but lost soil total nitrogen (STN), and the stockless cash crop system had a significant SOM loss in the magnitude of 7.7 t SOM ha^?1, or roughly 8.4% of the initial SOM mass. Reducing tillage intensity had no impact on SOM masses, but only on organic matter stratification in soils. We conclude that specialization of organic farms towards stockless arable crop production requires special attention on SOM reproduction to avoid detrimental effects. Further, reduced tillage intensity does not necessarily have a positive effect on SOM.  相似文献   

Closing the compliance gap in marine protected areas with human behavioural sciences     

Brock J. Bergseth  Adrian Arias  Michele L. Barnes  Iain Caldwell  Amber Datta  Stefan Gelcich  Sam H. Ham  Jacqueline D. Lau  Cristina Ruano-Chamorro  Patrick Smallhorn-West  Damian Weekers  Jessica Zamborain-Mason  Joshua E. Cinner 《Fish and Fisheries》2023,24(4):695-704

Advocates, practitioners and policy-makers continue to use and advocate for marine protected areas (MPAs) to meet global ocean protection targets. Yet many of the worlds MPAs, and especially no-take MPAs, are plagued by poaching and ineffective governance. Using a global dataset on coral reefs as an example, we quantify the potential ecological gains of governing MPAs to increase compliance, which we call the ‘compliance gap’. Using ecological simulations based on model posteriors of joint Bayesian hierarchical models, we demonstrate how increased compliance in no-take MPAs could nearly double target fish biomass (91% increases in median fish biomass), and result in a 292% higher likelihood of encountering top predators. Achieving these gains and closing the compliance gap necessitates a substantial shift in approach and practice to go beyond optimizing enforcement, and towards governing for compliance. This will require engaging and integrating a broad suite of actors, principles, and practices across three key domains: (i)) harnessing social influence, (ii) integrating equity principles, and (iii) aligning incentives through market-based instruments. Empowering and shaping communication between actor groups (e.g., between fishers, practitioners, and policy-makers) using theoretically underpinned approaches from the behavioural sciences is one of the most essential, but often underserved aspects of governing MPAs. We therefore close by highlighting how this cross-cutting tool could be further integrated in governance to bolster high levels of compliance in MPAs.  相似文献   

Molecular cloning of complementary DNA from a pneumopathic strain of bovine viral diarrhea virus and its diagnostic application.   总被引：2，自引：2，他引：0       下载免费PDF全文

K V Brock  D A Brian  B T Rouse    L N Potgieter 《Canadian journal of veterinary research》1988,52(4):451-457

A pneumopathic strain of bovine viral diarrhea virus was grown in cell culture and purified. Genomic ribonucleic acid was extracted, polyadenylated at the 3' end, and copied into complementary DNA after oligo-dT priming. Complementary DNA was male double stranded and cloned into the pUC9 plasmid. Approximately 200 complementary DNA clones varying in length from 0.5 to 2.5 kilobases were obtained. Hybridization assays indicated that the sequences isolated were specific for bovine viral diarrhea virus and that at least 5.5 kilobases of bovine viral diarrhea virus genome was represented in the library of complementary DNA clones, the majority of which may have originated from the 3' end of the virus genome. One cloned complementary DNA sequence was used as a 32P-labelled hybridization probe for bovine viral diarrhea virus detection. The probe hybridized with all cytopathic and noncytopathic strains of bovine viral diarrhea virus tested and was 100 times more sensitive than infectivity assays for the detection of bovine viral diarrhea virus. Hybridization did not occur with nucleic acids from bovine coronavirus, bluetongue virus, bovine adenovirus or uninfected cell cultures. Native plasmid DNA sequences, labelled with 32P, did not hybridize with bovine viral diarrhea virus ribonucleic acid.  相似文献