Summer fertilisation: Promoting heat and drought tolerance in turfgrass

Meteorologists are once again predicting the arrival of the natural weather phenomenon El Niño, which is associated with drought and high temperatures. Heat and drought stress can damage turfgrasses. How can we protect our lawns and sports turf proactively? Summer fertilisation with targeted applications of potassium and silicon increases drought tolerance and reduces damage to turfgrass.

In principle, turfgrass species originating from cooler climatic zones are well adapted to the Central European climate. However, due to global warming and the associated climate changes, we are likely to experience more frequent periods of exceptionally high temperatures and limited natural rainfall in the future.

Potassium and silicon promote drought tolerance

Numerous publications have shown that targeted applications of potassium and silicon can increase drought tolerance and reduce damage to turfgrass.

COMPO EXPERT highlights three specific products: Kali Gazon, Kick® Wetting Agent and Vitanica® Si. These are three tools that help turf cope more effectively with drought conditions.

Potassium optimises the plant’s water management, reduces ineffective transpiration and promotes the resilience and recovery of turfgrass during the summer months. For conditioning turf and preparing it for drought and heat stress, a timely supplementary application of potassium using Kali Gazon is highly effective. Consider a summer fertilisation programme where the N:K ratio is at least 1:2. In practice, this can be achieved, for example, by applying Floranid® Twin Permanent at 3 kg/are in combination with Kali Gazon at 1.5 kg/are.

How does turfgrass respond to heat and drought stress?

Roots remain shallow and leaf necrosis (leaf death) may occur. Photosynthesis is reduced and plants become more susceptible to diseases. A timely application of potassium significantly reduces these symptoms. “Timely” means while rainfall is still expected or when sufficient moisture is available to dissolve the fertiliser granules. In addition, potassium supports recovery after drought damage has already occurred.

Silicon is not an essential plant nutrient, but it does offer several benefits, particularly for turfgrass. “Silicon plays an important role in various ways,” explains Robin Van Havermaet. “Firstly, it contributes to the strength of the grass leaf. When turfgrass absorbs silicon, it forms an additional layer that reinforces the cell wall and acts as a kind of insulating barrier. As a result, the grass loses less moisture.”

The COMPO EXPERT research centre investigated the use of Vitanica® Si under drought stress conditions and found that the wilting process in turfgrass started significantly later than in the untreated control group. Applications of 10 l/ha every two weeks consistently proved more effective than a single application of 20 l/ha. In addition to potassium and silicon, Vitanica® Si contains a third component: seaweed extract from Ecklonia maxima. This seaweed extract contains a high concentration of bioactive compounds, including antioxidants and phytohormones that contribute to heat tolerance. The unique concentration of phytohormones strongly stimulates root development. The more roots a plant develops, and the deeper those roots penetrate, the easier it becomes for the plant to access moisture and protect itself against drought stress.

Wetting agents optimise irrigation management

Kick® Wetting Agent helps improve soil moisture conditions in several ways. Both preventive and curative applications can help avoid localised dry spots. “During the summer, patches of dry turf sometimes appear throughout the lawn. One possible reason is that the soil in those areas becomes water repellent. The soil in those locations is simply different and more vulnerable. Kick® Wetting Agent prevents the development of dry spots and ensures that moisture can once again infiltrate the soil. In addition, Kick® Wetting Agent helps distribute water evenly both horizontally and vertically throughout the turf for up to three weeks. On irrigated turf surfaces, this results in a uniform appearance while ensuring that every drop of water is used efficiently.”

Action plan

To take practical measures that improve the drought and heat tolerance of turfgrass, it is advisable to apply a potassium-rich fertiliser such as Kali Gazon from June onwards. For turf revitalisation during the summer months and periods of extreme heat, preventive applications of Vitanica® Si are recommended as additional protection. Should dry spots nevertheless become visible in the turf, curative treatments with Kick® Wetting Agent can still be applied.