The Role of SoilTech on Turf Density

 

Question:

What effect does SoilTech have on turf cover and density, and turf color and color consistency which may contribute to the overall appearance of lawns?

 

Purpose:

This investigation was designed to determine if the application of SoilTech substantially improved the overall appearance of lawns enough to justify the application of the product. Soil scientists agree that compacted soils impact plant growth and health in many ways. This investigation was conducted approximately 60 days after SoilTech application and near the end of the summer where daytime temperatures for 2003 exceeded 100 degrees at least 18 times.

 

Test Sites:

SoilTech was applied to over 500 lawns by a large lawn care company at the rate of 4 oz per 1000 sq. ft. This company has seven branch locations throughout Oklahoma. These customers specifically requested the SoilTech application as an alternative to mechanical core aeration. One hundred and forty seven test sites were selected at random from the list of customers who requested the application, representing all seven locations.

 

Tests Performed:

Turf Cover:

Turf cover was evaluated by using a 36 sq. in. quadrat frame sampler with ten random repetitions per site. The total square inches of exposed soil was measured then subtracted from 36. This difference was then divided by 36 to determine the percent cover. The outcome represents an averaged result. The check was measured on the adjacent untreated area. The results were then assigned by using the following key:

	SoilTech		Untreated
Cover %	Number of Lawns and Over %
95-100%	106	72.1%	24	16.3%
85-94%	14	9.5%	37	25.2%
75-84%	15	10.2%	63	42.9%
65-74%	6	4.1%	11	7.5%
55-64%	1	0.7%	4	2.7%
45-54%	3	2.0%	5	3.4%
35-44%	0	0.0%	2	1.4%
25-34%	2	1.4%	1	0.7%

The Turf Cover investigation supports user claims that SoilTech increases turf cover. The results clearly illustrate the high turf cover percentage following application. As reported, 72.1% of the treated lawns had between 95-100% turf cover on their lawn. The check (adjacent lawns) had only 16.3% with 95-100% cover. The average cover for the SoilTech lawns was 93.5%.

 

Turf Shoot Density:

Turf shoot density was evaluated by randomly selecting ten repetitions per site. At each site 1.0 sq. in. was measured by counting the total number of shoots. Shoots are the stems that originate from the soil. Only shoots that had blades attached were counted. These ten sites were averaged for the final result. The check was counted on the adjacent untreated area. The results were then applied using the following key:

 

	SoilTech		Untreated
5+ shoots per sq. inch	53	36.1%	5	3.4%
4.4-5.0 shoots / sq. in.	58	39.5%	14	9.6%
3.7-4.3 shoots / sq. in.	24	16.3%	38	26.0%
3.0-3.6 shoots / sq. in.	5	3.4%	54	37.0%
2.3-2.9 shoots / sq. in	. 5	3.4%	21	14.4%
1.6-2.2 shoots / sq. in.	1	0.7%	9	6.2%
0.9-.5 shoots / sq. in.	1	0.7%	5	3.4%

The Turf Shoot Density investigation supports user claims that SoilTech increases turf density. Again the results clearly illustrate the high turf density after SoilTech application. As reported 75.6% of the treated lawns had turf density over 4.4 shoots per sq. in. The untreated lawns had only 13.3% of the lawns over 4.4 shoots per sq. in. This investigation supports the users' claims that SoilTech increases turf density.

 

Turf Tissue Color:

Turf color was evaluated by using the Munsell Color Charts for Plant Tissues. This method of color determination provides an exact match of the color of turf tissues. Ten random samples from the treated lawn and ten random samples from adjacent untreated area were matched for color.

 

The complete Munsell notation is written: Hue Value/Chroma

Three Classes of Hue:

7.5 GY          Dark Green Color

5 GY             Medium Green Colors

2.5 GY          Pale Green to Yellow

Healthy plant tissue for Bermuda and Fescue turf grass is indicated in decreasing quality:

Color	SoilTech		Untreated
7.5 GY 4/4	14	93.3%	1	6.7%
7.5 GY 5/6	2	66.7%	0	00.0%
7.5 GY 5/4	2	100.0%	1	33.3%
5 GY 3/4	2	100.0%	0	00.0%
5 GY 4/8	39	79.6%	10	20.4%
5 GY 4/6	71	62.8%	42	37.2%
5 GY 4/4	23	29.1%	56	70.9%
5 GY 5/8	7	28.0%	18	72.0%
5 GY 5/6	7	35.0%	13	65.0%
5 GY 5/4	5	21.7%	18	78.3%

Plant tissue stress for Bermuda and Fescue grass is indicated in increasing severity by:

	SoilTech		Untreated
5 GY 6/8	0	00.0%	2	100.0%
5 GY 6/6	0	00.0%	1	100.0%
5 GY 6/4	0	00.0%	2	100.0%
5 GY 7/4	0	00.0%	2	100.0%
2.5 GY 5/4	0	00.0%	1	100.0%
2.5 GY 5/2	1	16.7%	5	83.3%
Dormant	0	00.0%	1	100.0%

The Turf Tissue Color was designed to determine if SoilTech makes lawns greener than untreated lawns. The lawn care company using SoilTech was especially concerned about this since they depend on satisfied customers within an extremely competitive market. They strive to have the best yard in the area so as to maintain the excellent reputation they currently have. The results strongly indicate that SoilTech promotes greener lawns than the untreated lawns. A major reason for doing the investigation late in the summer was to compare SoilTech in the most extreme climate conditions. Major differences in color were noted as shown in the results section. Only one treated yard was in plant stress as compared to 14 untreated lawns. Review the results section again to compare the treated vs. untreated.

 

Turf Color Consistency:

Turf color consistency was determined by calculating the areas of color that were significantly less than the sampled Munsell Color Chart Rating for that particular lawn. These areas generally show up as "hot spots" or areas where severely compacted soils or other factors such as uneven watering or underlying parent material is near the surface. As noted above, this investigation occurred at the end of August 2003 following at least 18 days that exceeded 100 degrees F. Oklahoma summers (and especially this particular summer) are normally dry with little rain. The lack of adequate rainfall combined with extremely high daytime temperatures will induce severe stress on most lawns, even when irrigated. For this reason, this test included only lawns treated with SoilTech, because the untreated lawns in most cases had such severe stress that proper measurement of "hot spots" was very difficult. The sq. ft. of the area (in most cases the front lawn) minus the "hot spots" divided by the total area equals the "Turf Color Consistency" for the lawn. (e.g. front lawn = 1800 sq. ft minus the "hot spot" of 260 sq. ft. divided by 1800 =86% Turf Color Consistency). The values then were placed into the key as follows:

 

Value  Lawns Result:           

100% = 95-100       93      63.7%

90% = 85- 94          15      10.3%

80% = 75-84           20      13.7%

70% = 65-74           6        4.1%

60% = 55-64           4        2.7%

50% = 45-54           7        4.8%

40% = 35-44           1        0.7%

Average Turf Color Consistency: 91.1%

The Turf Color Consistency investigation supports user claims that SoilTech maintains consistent color throughout the lawn. This is not surprising in that when soil has been "aerated" many changes occur. Nutrients that were locked up are now released. Atmospheric oxygen and nitrogen diffuse into the soil thus increasing microbial activity converting raw elements into a usable plant food source. Water management improves by the increased pore space with soil that is now less compacted. The results indicate that the average turf color consistency after SoilTech application is 91.1%. Having consistency this high in late August is very encouraging. No evaluation on the untreated lawns was done mainly because the "hot spots" were too numerous and widespread making precise measurements very difficult. Photos of lawn comparisons help illustrate the difference of treated vs untreated lawns. Click here to go to the photo section.

Qualitative Assessment:

A qualitative assessment of the lawns was performed to compare the treated lawns with 20-30 lawns in the surrounding area. The assessments were made by walking through the area and making comparisons of turf cover, density, color, and color consistency. This assessment is crucial for professional lawn care applicators who depend on quality lawns in a competitive market. Ratings were then assigned to the treated lawn as shown below.

 

Best Yard                62      41.9%

Tied for Best           22      14.9%

Second Best            7        4.7%

Top 90%                 16      10.8%

Top 80%                 7        4.7%

Top 70%                 7        4.7%

Top 50%                 7        4.7%

Total: 86.4%

This assessment supports the claim by users that the application of SoilTech improves the health and overall appearance of their lawns.

 

Conclusion:

Each of the four tests supports the claims by users that SoilTech increases turf cover and makes lawns greener and thicker than before application. This investigation was performed in seven cities of Oklahoma: Lawton, Oklahoma City & Edmond, Enid, Stillwater, Ponca City, Bartlesville, and Tulsa & Broken Arrow. The tests were conducted on sandy loam, clay loam, gumbo, silty clay, and clay soils.