Surviving A Dry Spell
23 May 06 9:00With the first Emergency Drought Orders now issued for over a decade, water – or lack of it – is a key concern across large areas of the UK. Golf courses, sports facilities and amenity areas are under increasing pressure to reduce water use. 
Use of irrigation for sports turf areas is always high on the turf management agenda regarding environmental issues and sustainability. Over-use of irrigation systems in the past has been responsible for creating poor playing surfaces and encouraging sward invasion from weed grasses such as Poa annua.
Now we are seeing certain parts of the country affected by drought and restriction on water use for irrigating turf, it is vitally important for the turf manager to make sure their management practices are geared towards creating turf that is sustainable in drought conditions, or has minimal irrigation requirement.
Water is a valuable resource, especially in the form of available irrigation water. As part of an environmentally sound management programme the optimum use of irrigation is essential. Maintaining the correct level of water in the rootzone is essential in producing a playing surface of the highest quality. Too little available water, and turfgrass will suffer drought stress. But there are actions that can be taken to minimise this risk.
Agronomic Factors
A grass plant that is growing in drought conditions is growing under stress. A stronger plant will survive these conditions far better. To create a drought tolerant grass sward there are a number of factors that need to be considered:
- Reduce compaction. a healthy rootzone has to contain oxygen and adequate space for the roots to grow into. A compacted soil would restrict both of these as well as reducing the ability to drain
- Increase appropriate aeration. This helps to encourage deep rooting
- Reduce thatch build-up by Verti-cutting, grooming etc. This will help with drainage, disease prevention and improves the health of the grass plants
- Only use very light top dressing treatments and avoid completely in very dry conditions. The plant may not be strong enough to grow through the dressing
- Raise the height of cut. Even a small increase will mean a stronger plant
- Use hand mowers to reduce stress. This will ‘lighten the load’ you are physically putting on the turf and hence reduce compaction
- Encourage grass species that are tolerant of drought conditions. Fescue, Colonial bent grass, smooth stalk meadow grass etc
- Use appropriate nutrition to encourage rooting without excess vegetative growth. Maintain nutrients responsible for stomata regulation such as potassium (K), also calcium (Ca) for cell strength.
- Avoid high applications of nitrogen during drought stress. If the plant already has access to sufficient N and a good root system, excess nitrogen will cause the plant to produce excessive vegetative growth at the expense of the root system. This is especially important in the late spring when grasses are growing rapidly
- Use appropriate amounts of potassium in your nutritional input programme, as this can help reduce plant stress caused by drought. Photosynthesis and carbohydrate production are reduced when potassium is low
- Potassium is also used by the grass plant to help regulate stomata function. Stomata are small openings on the cuticle of the plant. Their function is to allow gases to enter and to help control water release from the surface of the plant. This function becomes vitally important during times of drought stress or low water availability.
Always use soil analysis to check where the nutrient levels are. Then use a suitable fertilizer and trace element programme to rectify any deficiencies
- It is especially important to maintain adequate levels of potassium and calcium for reasons previously given, so ensure that the fertilizer programme takes this into account.
- Due to the high risk of scorch in hot and dry conditions you should avoid high salt concentrations on the surface e.g. avoid over-use of high acid reaction fertilizers e.g. sulphate of ammonia
- Consider using controlled release fertilizers such as Scotts Sierrablen as a base feed. This type of fertilizer releases the nutrients gradually over a long period of time and therefore avoids scorching and flushes of growth
- Use liquid fertilizers, such as Greenmaster Liquid, on little-and-often basis, as this will give you the control to feed the turf when it needs it
- The use of a turf bio-stimulant will encourage mycorhyza. By including Scotts Greenmaster Blade as part of a fertilizer programme you will encourage roots to store essential carbohydrates, and encourage rooting. Deeper and longer rooting goes hand in hand with improved resistance to drought. Soil moisture is more accessible and a stronger plant means your turf is better able to stave off attacks from disease and infection
- The use of a turf wetting agent can help in more ways than just getting water deeper into the soil. H2Pro from Scotts not only significantly reduces the irrigation requirement of soils, but also gives effective relief from dry patch. As you can see from the table below, on natural soil 31mm of irrigation was needed to reach the optimum moisture content, but with H2Pro only 7mm was required. By using a wetting agent you will require less water
- The latest tool in the armoury to fight drought is Primo MAXX – this plant growth regulator serves to stop cell elongation and keep shoots and stems short. The aim is to divert energy production into more lateral growth – creating a denser, healthier sward – and encourage more root growth, which makes plants better able to withstand drought, heavy wear and stress
- Finally, it is important to ensure that you give your turf a late autumn nutrient application as this will help it to cope with the winter conditions and be prepared for the coming spring.