It’s always a tough call. Should we irrigate tonight or stretch it another day? Make the wrong decision and you’ll be hand-watering wilt tomorrow afternoon. So you decide to water, but how many minutes are required? Over-watering not only wastes water and money, but it also reduces playing conditions. Your past experiences guide these tough judgements. As water becomes scarcer and more expensive, data and models can help. The new irrigation planning tool in GreenKeeper will estimate when wilt is expected and aid irrigation scheduling decisions.
Soil moisture meters have made irrigation scheduling easier over the past twenty years. While these tools have definitely improved irrigation efficiency, they cannot predict where soil moisture levels will be in the future. Superintendents and field managers rely on their own past irrigation failures (handwatering afternoon wilt) and successes (no wilt) to develop a comfortable soil moisture goal at the beginning of each day. For example, on a hot an windy day, a manager may desire a morning soil moisture of 15%, but a value of 10% may be fine on a cool and cloudy day.
When setting up irrigation each night, managers need to guess where the moisture will be at the end of the day, and then guess how it will change after some amount of irrigation is applied. Another example, a superintendent heads home at 2PM knowing the greens were roughly 15% moisture that morning. Greens start to show wilt symptoms at 8% moisture. He might expect the water content to decline to 10% by day’s end, and he predicts the 12 minutes of irrigation will bring the moisture back to 15% the next morning. There is a ton of feel involved in all of these decisions, and managers generally error on the side of more water – and money – when hand-watering labor is scarce.
Greenkeeper App predicts soil moisture over time and following irrigation
A new soil moisture prediction tool has been created for the GreenKeeper App homepage. The Water Resource Planner has been in development for over three years. It will ask users to enter the average soil moisture from different management zones (i.e. greens, tees, etc.) and then GreenKeeper will show how the soil moisture is likely to change hourly for the four days. The tool predicts when wilt is expected to occur with a margin of error. Users can also add irrigation run-times to predict how soil moisture will change after an irrigation cycle has been completed.
GreenKeeper’s machine-learning technologies will improve accuracy of these soil moisture predictions as additional soil moisture readings are added by the user. The site learns how different surfaces use water during the day and how irrigation run-time changes soil moisture content by simply entering moisture readings in the morning and throughout the day.
Lance Lauer, CGCS has been using a simplified version of this soil moisture model at The Country Club of Castle Pines since 2022. It has saved water, improved the firmness of the playing surfaces, and provided his staff with confidence when scheduling irrigation. The water and money saved with the use of this model paid for a GreenKeeper App subscription in less than one month.
I began experimenting with the irrigation model that’s inside GreenKeeper to schedule Greens irrigation in 2022. It’s allowed us to lower our soil moisture percentage by nearly a third which has resulted in firmer yet fair playing conditions. The model guidance has allowed us to reduce overhead irrigation on Greens, saving roughly 54,000 gallons of water each week.
In 2023, we used the model to help schedule irrigation on Tees, Fairways and Approaches. Prior to the model guidance, our soil moisture goal each morning was 23% on these areas. We have since reduced that goal level down to 14.5% – again improving playing conditions with firmer surfaces. Fairway irrigation cycles have been reduced from four or more times each week to roughly twice a week; a weekly savings of roughly 421,000 gallons.
Member satisfaction with the playing conditions has drastically increased. There has been nothing but compliments about the firmer conditions. I also enjoy the money saved on water which is approximately $1,100/month.
The new Water Resource Planner can be found on the homepage of GreenKeeper App. Start your subscription today to create your course for the 2024 growing season at https://GreenKeeperApp.com. New accounts enjoy a 7-day free trial.