Tuesday, March 14, 2017

Saving Water Outdoors with Dr. Eban Bean

Last month I had the opportunity to assist Dr. Eban Bean, UF-ABE assistant professor in urban water resources engineering, during an equipment installation at research sites in Ocala. The residential locations feature cloud-based irrigation controllers (with mainline flow sensors), pressure-regulating spray bodies with multi-stream/multi-trajectory nozzles, and Florida-Friendly Landscaping! I could write an entire article just on how rare it is to see all those devices in one place! But the best part about these sites is what’s going on in the soil. Dr. Bean spoke with IrriGator on location to give us an inside look into this on-going research.

Research sites in Ocala (image E.Bean)
Where are we today?
EB: We’re at the sanctuary model home site within the On Top of the World development. Our study is looking at evaluating soil treatments and amendments to evaluate potential for irrigation reduction for turfgrass.

Can you tell us something about the treatments you’re studying?
EB: There are 10 homes in this model home site. Of those 10 we’re using 9 lots in our study. We divided them into 3 treatments.
  • One is the control – standard compacted soil that you might encounter after typical construction.
  • On another set of three we had the soil tilled down to a depth of about 5 to 6 inches.
  • And then on the last three sites we had the soil tilled but incorporated a compost amendment into the soil – that compost amendment would increase the organic matter which has been shown to increase soil water holding capacity. 

Tilling compost into the soil before adding sod (image E.Bean)
Tillage in agricultural settings has been shown to break up and mitigate compaction which would increase the amount of porosity or storage space in the soil to hold water. It will also allow for greater infiltration and maybe most important to the plant itself, it makes it a lot easier for the turfgrass or plants to put their roots into the soil and drive them deep.

Working with a cloud-based irrigation controller
Irrigation is an important aspect of this project. How are these landscapes being watered?
EB: These landscapes will be using the Hunter Hydrawise irrigation controllers, connected to a weather station that’s right here on the site. It will adjust irrigation based on the rainfall and weather conditions. We’re also putting soil moisture sensors in. Those are not controlling the irrigation. We’re just monitoring to evaluate what the difference in soil moisture is underneath the turfgrass. That should show us that if there’s more water that’s available, or higher soil moisture in the soils, then we wouldn’t need to irrigate as much and could cut back on the amount of irrigation that the turfgrass is receiving.

Text book soil moisture sensor installation 
Who else is collaborating on this study?
EB: Life Soils has provided the compost product – Command, a blend of sand and compost. Academic partners include Allan Bacon, from Soil Water Science, who is overseeing our soil sampling and analysis - looking at particle size distribution, soil organic matter, pH, bulk density and looking at how compact it is. From Environmental Horticulture, Jason Kruse is doing turfgrass evaluation monthly – measuring the level of greenness, doing biomass harvesting and looking at other metrics for turf quality as well. 

Lloyd Singleton prepares a soil sensor data logger
Lloyd Singleton from Sumter County Extension is working on this as part of his Masters in Agroecology. He’s looking at the water-balance and water metrics here. On Top of the World has been a fantastic partner. These model homes won’t be lived in for up to 5 years and our study is going at least 2 years. I can’t speak highly enough about their cooperation and how they’ve helped with coordinating the construction, development and amendments. It’s a great project to be on and part of this is working with such great partners.

What is the big picture impact here? This data can help inform which practices?
EB: This study is a proof of concept to look at the benefits of two practices: tillage just by itself and also the incorporation of a compost amendment. Those could be seen as two different recommendations. We can recommend tillage to some depth. We can also recommend tillage with a compost amendment. The big picture here is looking at ways that we can reduce irrigation. Here we’re in the Southwest Florida Water Management District and the numbers I’m aware of suggest somewhere around 60% of a home’s water use goes to landscape irrigation.  

Soil moisture sensor data logger in action 
On Top of the World is a unique opportunity. When this development received its water permit, it agreed to a water-use rate of 150 gallons per home daily, which is much less than typical usage (around 250 gallons daily). They are really looking at ways that they can reduce water consumption. Everything inside the home is high-efficiency, so the landscape is an opportunity where we can have some cost savings, and it’s also a place where a lot of water is used any way. They’re already using Florida-Friendly Landscaping here which reduces irrigation demand. 
Dr. Bean informs development & water district staff on the study
(image E.Bean)
So we’re looking at ways to further reduce water-use by causing the turfgrass to need less irrigation and potentially have some additional benefits with the compost providing some nutrients and reduce the need for fertilizer. The big picture here is can we give homeowners the same turfgrass experience and use less water. That’s the objective here: the same quality of turfgrass – same look, same feel – but it just doesn’t require as much water. That is a win for everybody: the producers, the water managers, the developers, the consumers. If we can make that more efficient that is a big plus for everybody.


Lloyd Singleton, urban horticulture agent with Sumter County Extension, presents on this research during day one of this week's Urban Landscape Summit.


1 comment: