1999 Iowa Turfgrass Research Report


Modifying Athletic Field Soils with Calcined Clay and Tillage

 

David D. Minner and Jeffrey J. Salmond

 

The objective of this study was to evaluate calcined clay in a tilling renovation process and its effects on turfgrass growth.

 

A study was initiated in November 1997, at an Ames High School football practice field in Ames, Iowa, to evaluate calcined clay (Turface® MVP) in a tilled renovation procedure. The study was conducted on a separate irrigated practice field (different from the calcined clay topdressing study). The 15,750 sq. ft. experimental plot area was arranged between the hash marks and the goal lines. Each individual plot measured 15 ft. by 50 ft., and was centered on every yard line marker (goal line, 5, 10, 15, 20, etc.) (Table 1) such that 7.5 ft. was on one side of the yard line and 7.5 ft. was on the other side of the same yard line. Treatments consisted of calcined clay at 1 ton/1000 sq. ft., calcined clay at 2 tons/1000 sq. ft., and an untreated control (Table 2). Treatments were completely randomized and replicated seven times. Each replication was 45 ft. by 50 ft. with three treatments. Treatments were topdressed at their respective rate and tilled into the top 4 inches of soil with a Rotadairon (Bryan Wood, Commercial Turf & Tractor). The Rotadairon is used to level a playing surface and prepares the seed bed while burying roots, rocks, clods, clumps, or grass. The untreated control contained no amendment and was tilled.

 

The total plot area was seeded in May 1998 with a bluegrass blend containing ‘Nublue’, ‘Limousine’, and ‘Touchdown’. The field is used primarily for fall football practice (September through November) and spring soccer (April and May). Football in the fall of 1998 and soccer in the spring of 1999 resulted in substantial wear in the center of the field. Because of the two different sports, the wear pattern has not been consistent. Football wear was concentrated around each 5-yard line where the ball was placed to restart a practice set. Soccer wears out the center circle and the penalty and goalie areas. In the worn areas, the grass has been completely removed and bare soil is exposed. A visible response from treatments, based on traffic, was not apparent in the fall of 1998 or spring of 1999. In the summer of 1998, when the grass was establishing, there was a noticeable difference in the green color of both the turfgrass and the crabgrass weeds. The highest rate of Turface had the lightest green color followed by the low rate of Turface. The non-Turface control plot had a normal, dark green appearance. After applying 1.0 lb N/1000 sq. ft. to the entire study area in August, the Turface plots produced an acceptable green color that was similar to the control plots. There was no difference in turf color among treatments during the spring of 1999.

 

The inconsistent wear patterns on the research area made it difficult to determine if there were true treatment differences, even though there were seven reps and very large plots. The field was cored on 3-inch centers with 0.75-inch hollow tines on 9 June 1999. Cores were dragged within each plot and the area was drill seeded in three directions with a drill seeder.

 

It is too early in this research project to determine if tilling Turface into a field will help maintain better grass under intense traffic. However, we have observed that the Turface-treated plots dry quicker and make a better playing surface when the soil is exposed on worn areas. The Turface-treaded areas also are easier to penetrate when the field playing conditions are normally hard and dry.

 

 

 

  •  

    Table 1. Experimental plot layout of calcined clay tilled renovation. Treatments were applied on November 13, 1997.

    •

    [Center of field]
    Plot #

     

    Goal Line

    ________3________
    1
    Plot size is

    50 x 15 ft

    1
    2

    REP 1

    2
    3

    1
    4
    Plots are centered

    between hash marks

    3
    5

    REP 2

    2
    6

    3
    7
    Each 5-yard line is the

    center of the plot

    1
    8

    REP 3

    2
    9

    1
    10

    50-yd Line

    ________2________
    11

    REP 4

    3
    12

    1
    13

    2
    14

    REP 5

    3
    15

    1
    16

    3
    17

    REP 6

    2
    18

    3
    19

    2
    20

    REP 7

    Goal Line

    ________1________
    21

     

     

     

    Table 2. Treatment listing and respective rates.

     

    Treatment
    Rate

    (tons/1000 ft2)
    1

    Turface

    1
    2

    Turface

    2
    3

    Untreated control*

    NA

    Turface applied to plots with topdresser and then tilled with Rotadairon to 4-inch depth.

    *Untreated control received no amendment but was tilled with the Rotadairon.

    Iowa State University ISU Horticulture:Publications:1999 Turfgrass Report College of Agriculture