Dealing with Drought Part 2
Once drought and heat have arrived, the goal for turfgrass management moves from improving colour and growth to maintaining stability and survival. The good news is that even brown turf may be dormant rather than dead!
Dormancy allows the turfgrass plant to protect itself from extreme heat and drought by reducing or stopping growing, drying up and wilting, and losing the green colouring. The appearance of dormancy should be a gradual and uniform process when it is due to heat and drought stress.
Recovery is possible from dormant grass plants because the crown is still active and able to generate new shoots once suitable conditions return.
Sudden changes in the colour, condition and quality of the turf in smaller areas could be due to localised dry patch but should be investigated to rule out any other factors such as disease that could be contributing to turf decline rather than dormancy.
Managing Localised Dry Patch
Where localised dry patch is identified it can be alleviated through the use of wetting agents such as H2Pro TriSmart, or AquaZorb 45 which reduce the surface tension of water allowing it to move more uniformly through the rootzone.
Alternatively, granular wetting agents such as H2Pro Conserve and Aquaduct Flex enable accurate targeting of localised dry spots as well as the ease of a granular application.
Irrigation Strategy During Heat and Drought
If you do have the luxury of being able to apply water, then make sure to water slowly and deeply. Only irrigate at the speed of infiltration into the soil to avoid pooling and apply enough water to wet the whole depth of the rootzone if possible.
It is better to water less frequently but apply more water on each irrigation event because this will encourage deeper rooting than applying a small amount of water more often.
Be aware that even the best irrigation systems are unlikely to apply water evenly across the whole surface so pay particular attention to irrigation uniformity.
If access to water is limited it can also be beneficial to consider splitting the turfgrass area into priority zones. Prioritise areas which are likely to receive a lot of wear, that are important visually or for playing quality, or which are known to be more affected by reduced water availability.
Nutrition During Heat and Drought Stress
It can be important to ensure that turf is adequately fertilised ahead of heat and drought stress periods as a healthy sward is more likely to deal with the stresses well.
Once heat and drought stress is present it can be risky to over fertilise, particularly with high nitrogen feeds. Excessive levels of nitrogen fertiliser can encourage rapid shoot growth which increases water demand and produces more succulent leaf tissues that are more drought sensitive.
In addition, dormant turf is unable to make use of nitrogen applications resulting in the potential for increasing nitrogen losses to the environment and wasting resources.
Slow and controlled release products can be a useful way of providing a low dose of nutrition when conditions are suitable for growth.
Minimising Additional Stress
Finally, when heat and drought are present, try to avoid taking actions which will stress the turfgrass unnecessarily.
For example, herbicides, fungicides or even liquid fertilisers should only be applied when absolutely required and according to label directions to ensure effectiveness against their target without negatively impacting turf health.
