Climates are getting warmer and wetter, and superintendents will have to adapt. That was the subject of the keynote address at the Ohio Turfgrass Conference & Show, which took place Dec. 9 in Columbus, Ohio.
Al Turgeon, Ph.D., professor of turfgrass management at Penn State, presented, “Implications of Global Warming: Cultural Relief and Future Management Strategies.” Turgeon led by saying he’s not a climatologist; rather, he’s an agronomist with an interest in climate change’s impact on his field of study.
“The implications for turfgrass are real,” he said.
The world is, and has been, in a warming trend for some time, Turgeon said. For example, 30,000 years ago 30 percent of the world was covered by ice, compared to 10 percent today. A shorter-term example comes from the pages of Turgeon’s book, “Turfgrass Management.” The map of world climates that appears in its early pages has had to change considerably, reflecting warmer climates, since the first edition was published in 1980.
Politics of global warming
The political side of the climate-change debate – whether or not humans are a contributing factor – has two diametrically opposed points of view. The book by Thomas Friedman, “Hot, Flat and Crowded: Why We Need a Green Revolution and How it Can Renew America,” is representative of one side’s views. The other side agrees with author Christopher Horner and his book, “Red Hot Lies: How Global Warming Alarmists Use Threats, Fraud, and Deception to Keep You Misinformed.”
If the first camp is right, Turgeon says that means the situation is caused or exacerbated by man and the magnitude of these problems may depend on corrective actions taken now and in future years. If they’re not right, there may still be a problem; however, there’s nothing humans can do to reverse it.
In any case, it’s true the earth’s atmospheric temperatures experience cyclical variation over time, we appear to be in a warming portion of the cycle and increased production of greenhouse gases is likely exacerbating the warming effect. What’s not clear is how severe the consequences of higher greenhouse gas concentrations will be.
What superintendents should do
Regardless, turfgrass managers will have to adapt, Turgeon says, citing the following likely consequences for turf, as a result to milder winters and more severe summers:
- More flooding during storm events;
- More moisture stress from more severe and longer droughts;
- More carbohydrate stress from higher rates of photorespiration in cool-season (C3) turfgrasses;
- More phytohormone stress from reduced cytokinin production in roots; and
- More oxidative stress from more oxygen radical production and less antioxidant production.
To reduce global warming potential, turfgrass managers should consider optimizing their nitrogen use, conserving energy resources at home and work and reducing atmospheric pollution, Turgeon says. To deal with the consequences, turfgrass managers may have to switch to better adapted turfgrasses, improve surface and internal drainage and adjust cultural and pest management practices. The following turfgrass species changes may be in play for greens:
- Colonial bentgrass to creeping bentgrass
- Annual bluegrass to creeping bentgrass
- Creeping bentgrass to bermudagrass
- Bermudagrass to seashore paspalum.
For fairways, consider the following turfgrass species changes:
- Colonial bentgrass to creeping bentgrass
- Annual bluegrass to creeping bentgrass
- Creeping bentgrass and pr. ryegrass to bermudagrass and zoysiagrass
- Bermudagrass to seashore paspalum.
Turfgrass managers also should consider alterations to cultural operations, as suggested by Turgeon in the chart below, to deal with the potential consequences of climate change.
Dealing with climate change – cultural operations to consider:
Mowing
- Raise mowing heights in the summer.
- Mow more frequently.
Fertilization
- Increase the amount of fertilizer nutrients applied because of the longer growing season and alternate turfgrass species.
- Employ, to an even greater extent, spoon-feeding of soluble nitrogen during the summer months because of the impact of heat and drought stresses.
Irrigation
- Increase the amount of water applied during the growing season in response to higher ET rates.
- Employ syringing on greens during periods of severe heat and drought stress.
Cultivation and topdressing
- Increase the intensity, nature and frequency of cultivation practices to control thatch accumulations and alleviate the effects of soil compaction.
- Increase the frequency of topdressing to control thatch accumulations and change the nature of the growth medium where it’s unsuitable.
Wetting agents
- Higher heat and drought stresses promote faster drying of sand, leading to a water repellency problem called localized dry spot or dry patch.
- The combination of core cultivation and wetting-agent application can help to deal with dry patch.
Phytohormones and antioxidants
- Plant-growth regulators are used widely to inhibit GA biosynthesis – limiting vertical shoot growth and promoting tillering – to enable plants to better withstand stress.
- Cytokinins could be used to promote root growth where high summer temperatures inhibit it.
- ABA and JA could be used to enhance drought stress tolerance in summer.
- Antioxidants could be used to neutralize oxygen radicals and alleviate oxidative stress.
Pest management
- More and different weeds, diseases, and insects can be problematic with increasing temperatures.
- Evolutionary development of these pests and associated pesticide resistance can be more problematic with increasing temperatures.
