Factors influencing the role of clover in grass-clover leys fertilized with nitrogen at different rates I. The effects of the variety of companion grass on the yields of total herbage and of clover

1961 ◽  
Vol 56 (2) ◽  
pp. 143-153 ◽  
Author(s):  
D. Reid

1. A study has been made of some of the factors influencing the role of clover in grass-clover swards fertilized with nitrogen at different rates.2. From 1955 to 1957 inclusive three nitrogen treatments, 0, 4 and 10 cwt. ‘Nitro-Chalk’ (15·5% N)/acre/season, were applied to twentyone grass-clover mixtures sown in the spring of 1954. The mixtures contained either S 184, S100 or Kersey white clover alone or in association with one of the following grasses, S 23 or S 24 perennial ryegrass, S143 or S37 cocksfoot, S48 timothy or S53 meadow fescue.

2011 ◽  
Vol 15 ◽  
pp. 39-46
Author(s):  
G.R. Edwards ◽  
D.F. Chapman

The effects of defoliation on plant morphology and the structure of perennial ryegrass and white clover populations are reviewed with reference to the persistence of yield in sown pastures. Maintenance of high densities of perennial ryegrass tillers and white clover stolons is fundamental to persistence. Tiller and stolon population densities are subject to within- and between-year variation, and are strongly influenced by defoliation management through processes such as competition for light, and size-density trade-offs mediated by self-thinning processes. Spring is a time when high tiller/stolon appearance and death rates occur simultaneously. Spring is also the time when clover populations undergo rapid structural change as large clover plants fragment to release small, unbranched plants with limited ability to compete for light with grasses. The central role of reproductive stem development in perennial ryegrass for summer survival of tillers and autumn re-establishment of tiller populations also highlights the importance of defoliation management during the spring for population persistence. Examples of the application of tactical defoliation management in spring, and at other times of the year, to manipulate stolon and tiller densities are presented. In some instances, such tactics may improve animal production potential, as well as the persistence of new cultivars. It is notable that the New Zealand literature on this topic is mostly more than 15 years old. Recent changes in farming systems and plant genotypes (e.g. tetraploidy in perennial ryegrass, late flowering perennial ryegrass) may require a reanalysis of established principles and practices related to defoliation x plant interactions in grazed pastures to ensure best possible pasture yield persistence and profitability of grazing systems. Keywords: grazing management, perennial ryegrass, persistence, population dynamics, white clover


2021 ◽  
Vol 17 ◽  
Author(s):  
Breanna Taylor ◽  
Anna Mills ◽  
Malcolm Smith ◽  
Richard Lucas ◽  
Derrick Moot

Dry matter yield and botanical composition of four grazed dryland pasture types were compared over 8 years in summer-dry conditions at Ashley Dene, Canterbury, New Zealand. The experiment was sown in March 2013 to evaluate cocksfoot (CF)- or meadow fescue/ryegrass hybrid (RG)-based pastures established with either subterranean (Sub) or subterranean and balansa (S+B) clovers. Plantain was included in all pasture types. Perennial ryegrass established poorly on the low soil moisture holding capacity Lismore soil and in Year 2 was re-broadcast into the RG pastures. Despite this, plantain was the main sown species in RG pastures beyond Year 3. Total spring yield was greatest in Year 5 at 6720 kg DM/ha and varied with spring rainfall. Cocksfoot-based pastures had 60% of sown species present in the spring of Year 8, compared with 28% in RG-based pastures. Balansa clover was only present up to Year 5 after a managed seeding event in the first spring. White clover did not persist in the dryland environment past Year 2. Sub clover yield depended on the time and amount of autumn rainfall but contributed up to 45% of the spring yield. Cocksfoot-sub clover pastures appear to be most resilient in this summer-dry environment with variable spring rainfall.


2021 ◽  
Vol 17 ◽  
Author(s):  
Kati Hewitt ◽  
Cory Matthew ◽  
Catherine McKenzie ◽  
Wade Mace ◽  
Alison Popay

The literature on the importance of Epichloë grass endophytes during pasture renewal is reviewed. Perennial ryegrass endophyte strains such as AR1, NEA2, and Standard Endophyte (SE) as well as tall fescue and meadow fescue endophytes, significantly increase seedling survival at establishment under insect pressure, for example from adult Argentine stem weevil, grass grub, and African black beetle. However, in endophyte-infected ryegrass, insect-derived plant damage increases 10–43 days after sowing despite the presence of endophyte. Insecticidal seed treatments can mitigate the vulnerability to insect predation during this time.


1961 ◽  
Vol 56 (2) ◽  
pp. 155-160 ◽  
Author(s):  
D. Reid

1. A brief description is given of an experiment in which some of the factors influencing the role of clover in grass—clover swards fertilized with nitrogen at different rates were studied.2. Reference is made to a previous paper detailing the experimental methods and reporting the results pertaining to the effects of the grass varieties included in the seeds mixture on the yields of mixed herbage and of clover. The effects of the clover varieties on these yields are discussed in the present paper.


Agronomie ◽  
2003 ◽  
Vol 23 (5-6) ◽  
pp. 503-510 ◽  
Author(s):  
Florence Paynel ◽  
Jean Bernard Cliquet

Author(s):  
D.W.R. White

Cell culture and genetic engineering techniques can be used to develop improved pasture plants. To utilise these methods we have developed procedures for regenerating plants from tissue cultures of perennial ryegrass and white clover. In both, the plant genotype influences regeneration capacity. There was significant genetic variation among regenerated perennial ryegrass plants in a wide range of characteristics. Most of the regenerants were resIstant to crown rust and this trait was highly heritable. This rust resistance is being used to breed a new ryegrass cultivar. A system for introducing cloned genes into white clover is described. This capability is bemg used to incorporate genes with the potential to improve nutritional quality and pest resistance. Other possibilities for engineering genetic improvements in white clover, genes conferring herbicide tolerance and resistance to white clover mosaic virus, are briefly outlined. Keywords: Lolium perenne, Trifolium repens, cell culture, somaclonal variation, crown rust resistance, transformation, cloned genes, nutritional quality, proteinase inhibitors, Bt toxins, pest resistance, WCMV viral cross-protection, herbicide tolerance, Agrobacterium, Bacillus thuringenisis.


2021 ◽  
Author(s):  
Lalit Yadav ◽  
Tiffany K Gill ◽  
Anita Taylor ◽  
Jen DeYoung ◽  
Mellick J Chehade

UNSTRUCTURED Introduction Majority of older people with hip fractures once admitted to acute hospital care are unable to return to their pre-fracture level of independence and a significant number are either newly admitted or return to residential aged care. Patient education involves family members and/or residential aged care staff as networked units, crucial for empowerment through improving health literacy. Advancement of digital technology has led to evolving solutions around optimising health care including self-management of chronic disease conditions and telerehabilitation. The aim of this study is to understand perspectives of older patients with hip fractures, their family members and residential aged carers, to inform the development of a digitally enabled model of care using a personalised digital health hub (pDHH). Methods A mixed methods study was conducted at a public tertiary care hospital in South Australia involving patients aged 50 years and above along with their family members and residential aged carers. Quantitative data, including basic demographic characteristics, access to computers and Internet were analysed using descriptive statistics. Spearman’s Rank Order Correlation was used to examine correlations between the perceived role of a pDHH in improving health and likelihood of subsequent usage. Whereas qualitative data included series of open-ended questions and findings were interpreted using constructs of capability, opportunity and motivation to help understand the factors influencing the likelihood of potential pDHH use Results Overall, 100 people were recruited in the study, representing 55 patients, 13 family members and 32 residential aged carers. The mean age of patients was 76.4 years (SD-8.4, age range 54-88) and females represented 60% of patients. Although a moderate negative correlation existed with increasing age and likelihood of pDHH usage (ρ= -0.50, p<0.001) the perceived role of the DHH in improving health had a strong positive correlation with the likelihood of pDHH usage by self (ρ=0.71, p<0.001) and by society, including friends and family members (ρ=0.75, p<0.001). Of particular note, almost all the patients (98%) believed they had a family member or friend /carer who would be able to help them to use a digital health platform. Whereas our qualitative findings suggest emphasising on complex interplay of capability, opportunity and motivation as crucial factors while designing a pDHH enabled model of care for hip fractures at a local context level. Conclusion Findings from this study contributed to understand the dynamics around capabilities, motivation and opportunities of patients, family members and formal carers as a “patient networked unit”. Future research recommendation must involve co-creation guided by iterative processes through improving understanding of factors influencing development and successful integration of complex digital healthcare interventions in real-world scenarios.


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