Stressed OUT!
and forward planning can help beat the stress of drought
JAYNE LEYLAND looks at how species selection
Barenbrug’s
SO FAR, 2006 has been a highly stressful year for grass - and for groundsmen and greenkeepers too! For most of the country spring was late and unseasonably cold, resulting in very slow spring recovery. There was frost in May and, unusually, sand rootzone temperatures in the south east of the UK struggled to reach 80O
there was little growth until June. From this we went straight into drought and heat stress from early June onwards. Because of the continued stress, Poa annua seeded heavily for an extended period, leading to an extraordinary amount of Poa germination in existing swards. Unfortunately this has exacerbated the impact of the drought/heat stress, particularly for those who do not have the resources to maintain this type of sward. The prolonged spell of hot, dry weather has been a painful experience for many, particularly those who are under pressure to present a green sward whatever the conditions. But, on the positive side, it has presented an excellent, and for some, long- awaited opportunity to introduce more desirable species and cultivars, or to begin complete species exchange programmes. Whatever your situation, the important thing now is to plan and prepare for what nature may have next in store.
Species selection for drought
DIFFERENT species of grasses have different physiological features that enable them to survive and recover from drought. Characteristics such as deep rooting capability, aggressive rhizome production for recovery, high root density, waxy leaf coating and slower translocation are essential attributes that enable individual species to survive.
... an excellent opportunity to introduce more desirable species
experience a repeat of 2006 summer conditions next year, but what we can do is prepare. Combining drought tolerant species - each with its own individual characteristics for specific applications - with traditional species in mixtures offers real solutions. Cultivars of traditional species, for example perennial ryegrass (Lolium perenne), exhibit variable tolerance to drought and heat stress so, with careful cultivar selection, you can achieve improved tolerance from this species for heavy duty sports applications. Sometimes it is a question of degrees of improvements over time, especially for golf courses. For example, changing from cultivars with high water demand (e.g. creeping bent tees
No one knows if we will For most parts of Scotland C.
and fairways) to a combination of drought/heat tolerant perennial ryegrass (Lolium perenne) and using these cultivars together with drought tolerant fescue mixtures containing hard fescue (Festuca ovina duriuscula) can help you reduce water requirements without compromising on playing quality. For golf greens, some cultivars of bent grass (Agrostis capillaris) have superior drought tolerance without the loss of winter quality e.g. BarKing.
Drought tolerance without compromise
ALTHOUGH choosing the most drought tolerant cultivars from traditional species will undoubtedly help, now is perhaps the right time to consider one or more of several different species which offer superior drought tolerance, all with very different characteristics.
RTF Rhizomatous Tall Fescue (Festuca arundinacea) is a remarkable species which, through its amazing rooting depth capability, can tolerate both drought and waterlogging (nature may restore the balance in 2006 with a wet winter). RTF increases this capability by producing underground stems (rhizomes), offering unrivalled recovery and tensile strength, plus the added benefit of incredibly fast establishment when laid as turf, which could be critical in terms of water conservation. Its wear tolerance is similar to perennial ryegrass once established.
Crested hairgrass (Koeleria macrantha) thrives under minimal water and nitrogen regimes and produces very little thatch. It is in fact the ultimate sustainable grass; low maintenance inputs with high aesthetic quality. It has been successfully utilised with slender creeping red fescue where the irrigation source is treated effluent water.
Hard fescue (Festuca ovina duriuscula) is little known or used in comparison with red fescues (Festuca rubra spp.) but it has superior drought tolerance. It is extremely fine-leaved with high shoot density and has outstanding survival capabilities in both heat/drought and cold/drought stress. Furthermore, it has excellent natural shade tolerance. It is a species which has been overlooked, but new cultivars with improved characteristics means hard fescue should become very important for the future of fine turf as the potential for water restrictions increases. What is extremely important for the future is the recovery capability of these new species
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