Trinity Valley students examine soil samples for microbes to assess its condition. Photos courtesy of Billy Schlee​.

July 11, 2017

Ninth grade science students at Trinity Valley School in Fort Worth are conducting research that could push the landscaping industry and homeowners to adopt more eco-friendly practices.

The year-long study, started last May, will explore the viability of using soil microbiology and organic practices to improve soil fertility in contrast to conventional methods that are highly dependent on synthetic, agricultural chemicals.

Trinity Valley soil studyGetting their hands dirty as they undertake a real-world application of the science they’re learning in the classroom, about 20 students began the study by collecting soil samples in the central courtyard on campus. As the study continues, they’ll track any changes that occur in the soil as the test site is subjected to organic gardening practices.

Trinity Valley facilities director Cage Bass and students taking soil compaction readings with a penetrometer.

“We took the initial data to establish a baseline of information to test our trials against. The students and myself have taken soil samples and sent those off to a lab to measure a number of different parameters in the soil. We have also taken soil compaction readings and recorded that data,” says Billy Schlee, leader of the study and a soil consultant for Preservation Tree Services in Fort Worth. “We also identified many of the types of organisms in the existing soil under a microscope. I have taken a biomass analysis of the existing organisms. In the end we will take the same readings and compare the data to see if our methods improved soil health.”

Trinity Valley soil studySchlee says organic practices are largely unresearched, but the growing body of evidence about conventional gardening and farming practices shows a need to transition away from viewing soil as simply an inert growing medium.

Soil samples pulled by students.

Currently, the landscaping industry overcomes problems with soil quality by the heavy application of synthetic fertilizers and pesticides, Schlee says. These practices fail to remediate the underlying problems and actually contribute to the decline of the soil’s viability by killing the underground ecosystem of microorganisms that feed plants and aerate the soil, a concept familiar to followers of Dallas-based organic gardening advocate, radio host and author Howard Garrett, aka the Dirt Doctor, who received the Green Source DFW Sustainable Leadership Award for Lifetime Achievement last year.

“Due to the previous construction project of building the school, much of the good topsoil was shipped off, which left compacted and inert low quality subsoils as the medium to grow plants. You can only grow plants in unfavorable conditions while constantly feeding them synthetic fertilizers for so long until the system fails,” Schlee explains. “Then you have to replant and start the process over again every year or two. It’s very costly and time consuming. Simply put, it’s not sustainable.”

"You can only grow plants in unfavorable conditions while constantly feeding them synthetic fertilizers for so long until the system fails.”

Trinity Valley soil studyThe experiment involves the use of a liquid derived from composted plant waste to fertilize the soil, along with other organic practices such as working beneficial microorganisms into the ground. The microorganisms make nutrients available to plant roots and prey on soil pests. Additionally, Schlee will use a special soil aerator to relieve the site’s compaction. Most importantly, no synthetic pesticides or fertilizers will be applied to the test area.

“Synthetic fertilizers do nothing for building sustainable soils that can essentially manage themselves,” Schlee says. “Almost everything we do is to build organic matter in the soil and increase biological activity so that soils can sustain themselves over time. All of our methods increase the soil’s ability to hold more water, hold more nutrients and provide a suitable environment for beneficial microorganisms to thrive. All of which encourages a very sustainable low input environment that drives optimal plant health.”

Schlee says the test site is a good representation of what surrounds most homes, which is why Preservation Tree Service C.E.O. A.J. Thibodeaux chose it for testing purposes. 

“This entire site as well as most residential properties is heavily compacted,” Schlee says. 

Because of this, water and nutrients are unable to penetrate the soil and reach roots, which also leads to disease and pest issues. 

“Synthetic fertilizers do nothing for building sustainable soils that can essentially manage themselves.” 

Schlee says the findings will serve as preliminary results for further investigation. He expects the data to support Preservation Tree Services’ own organic program and hopes the students involved will be inspired by the science they learn.

Trinity Valley soil studySoil study area after the soil was top dressed with compost and organic fertilizer was spread. This other photo shows the greening of the turf a week later.

Trinity Valley soil study“This is a real experiment but it’s preliminary to publishable work. When we discussed doing an experiment with Trinity Valley School, we wanted to involve the students, as much as they wanted us to,” Schlee says. “How often does a classroom get to interact in real world applications of the science courses they are learning? Then to see the results of their labors implemented on their campus gives them a sense of pride and ownership in themselves, their education, and their school.

“The students will first learn the principles of the soil food web and its role in soil health, as well as the practical application of these principles. Then they will learn basic agronomy or soil science to understand how we are planning to use microorganisms and organic fertilizers including our proprietary Seasons Bio-fertilizer to manipulate or change the existing conditions of the soil. The students pulled soil samples, took readings, recorded data and they will do the same thing once school starts again. We will also have the students analyze the data to draw conclusions about the experiment.”

If the findings indicate that organic practices are cost-effective in remediating poor soils, Schlee says they’ll serve as a marketing tool for Preservation Tree Services and, he hopes, motivate the landscaping industry as a whole to move toward more sustainable practices.

“There is no doubt this promotes our company but we mostly want to promote the use and viability of organics as a sustainable method to plant health care,” Schlee says. “This experiment is an effort to be leaders in our industry and encourage others to follow, to give back to the community and provide our customers with empirical evidence to back the success of our program.”


North Texan Howard Garrett has sown seeds of organic gardening nationwide

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