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Kildare, Ireland

Shah F.A.,University of Swansea | Greig C.,University of Swansea | Hutwimmer S.,University of Innsbruck | Strasser H.,University of Innsbruck | And 3 more authors.
Fungal Ecology | Year: 2010

Amending plant growing media with biocontrol agents is becoming an increasingly popular strategy for protecting plants against insect pests and diseases. Although this practice offers potential for pest and disease control, very little is known about the influence of introduced microbes on the indigenous microbial communities and vice versa. This study examines fungal and bacterial community structures of diverse horticultural growing media and evaluates their interactions with a plant Euonymus fortunei and/or the insect pathogenic fungus Metarhizium anisopliae. Complementary physiological (Biolog™) and molecular (automated ribosomal intergenic space analysis - ARISA) techniques were applied to analyse community structure and diversity over 1 yr. These studies clearly showed distinct microbial communities in different plant growing media. Irrespective of media or any treatment, initial microbial diversity was very low but increased significantly over 1 yr. A succession of new fungal and bacterial species was observed, with species originally present being displaced. This succession led to the establishment of distinct microbial community structures for each medium over 6-12 months. ARISA studies showed that bacterial and fungal community profiles were influenced by the presence of plant and M. anisopliae, but in complex ways depending on the medium. Certain microbes were specifically associated or inhibited by the presence of M. anisopliae and/or E. fortunei. Physiological studies, however, showed that neither M. anisopliae nor plant had any significant effect on the communities' ability to decomposition a batch of carbon sources. Although diverse microbial communities were observed in different media, none of these communities influenced the efficacy of M. anisopliae. © 2010 Elsevier Ltd and The British Mycological Society.

Carlile B.,Bord Na Mona Horticulture | Coules A.,Nottingham Trent University
Acta Horticulturae | Year: 2013

Sustainability is commonly defined as the capacity to endure, with the World Summit of 2005 defining it as a reconciliation of environmental, social and economic demands: the three pillars of sustainability. In terms of sustainability of growing media, peat has been identified by environmental lobbyists as an unsustainable constituent in terms of habitat destruction and potential contribution to climate change. The activities of lobby groups have influenced the U.K. government: indeed a recent White paper issued by the U.K. government proposes phasing out peat in U.K. retail horticultural markets by 2020, and in the professional sector by 2030. Manufacturers and retailers have reacted to the issue of peat use in growing media by developing alternative materials including wood fibre, green compost, composted bark and coir. The consequent rapid use of alternative materials to peat within the U.K., despite innovative research by several manufacturers, has led to media of very variable quality arriving in retail markets, in turn giving rise to concern among many professional horticulturists. This paper examines the rationale behind the proposals that peat is an unsustainable medium, and that other media are more sustainable. Sustainability is addressed not only in a narrow environmental sense in terms of climate change and biodiversity, but also from an economic perspective through the ability of growing media providers and manufacturers and their customers to survive and prosper. Finally, the third pillar of sustainability, that of community and social sustainability, in which horticulture plays a prominent part in rural locations, is briefly addressed.

Doyle O.,University College Dublin | Delaney M.,University College Dublin | O'Haire R.,University College Dublin | Barry J.,University College Dublin | And 3 more authors.
Acta Horticulturae | Year: 2013

Within the European Union the control of plant diseases has become more challenging in recent years due to the reduction in the number of available plant protection products. Alternatives to chemical control of plant diseases are being sought. One of the most destructive plant diseases is damping off caused by Pythium spp. This study examined the possible use of composted green waste (CGW) materials as a potential control method for this disease. The study evaluated the effects of different growing media, containing composted green waste, on the occurrence and development of Pythium. Three separate experiments were undertaken using two isolates of Pythium and seeds of lettuce (Lactuca sativa) cultivar 'Little Gem'. The study found that the addition of CGW, either as a surface application or by incorporation into a peat-based medium diminished the impact of Pythium spp. on the germination and growth of lettuce. The effect is dependant on the sample of CGW used and varied between isolates of Pythium.

Doyle O.,University College Dublin | Courtney S.,University College Dublin | O'Haire R.,University College Dublin | Barry J.,University College Dublin | And 3 more authors.
Acta Horticulturae | Year: 2013

The reduction in peat usage is an important issue in U.K. horticulture, a major destination for growing media produced in the Republic of Ireland. This study examined the possibility of using composted seafood waste (CSW) in a traditional peat based medium and in a peat reduced medium containing composted green waste (CGW). The growth and development of tomato test plants (Lycopersicon lycopersicum var. Shirley), grown in peat based and peat/CGW media with reduced fertiliser rate (50%) amended with three levels of CSW added at rates of 0, 5 and 10% (v/v), was assessed. The objective was to examine if composted seafood waste could compensate for the reduced fertilizer level in these growing media. The plant growth parameters examined were plant height, plant spread, fresh shoot weight and percentage dry matter. Overall performance improved with the addition of CSW. The addition of CSW at 10% to the reduced fertilized peat medium and a 5% addition of CSW to the reduced fertilized Peat/CGW medium produced the most favourable results. Plants in these treatments were not significantly different from each other and only had one significant difference from their controls in terms of % dry matter. The addition of CSW at 5% to the peat media also produced favourable results. The addition of CSW at 10% to the peat/CGW medium produced poor plants. It is concluded that the addition of CSW at an appropriate rate can produce tomato plants of acceptable quality. However, the immobilisation of phosphorus by CSW could result in restrictions to plant growth and development.

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