Introduction to Core Aerification and Topdressing Model

     This web site uses computer modeling to calculate numbers of core and/or top dressing needed to reach certain sand percentage by weight (gravimetric percentage) in a sports turf field based on parameters input by users.  It also allows users to estimate or evaluate the efficacy of combinations of different practices.

     We can start from eight different scenarios from various combinations of topdressing, aerification with or without core-removing.  Of the eight combinations, only five are practical (Table 1), i.e. case one to five.  It is obvious that case 3 plus case 4 is equivalent to case 1.  Therefore, only case one, case two, and case four are considered in the model.  In addition to different parameters, two root-zone types are included, one is soil-based medium and the other is sand-based medium with a sod layer of high clay content.

 Table 1. Combination of Coring and Topdressing Practices.

Case #	Coring	Moving Cores	Topdressing with Sand	Effects on Sand Percentage
1	+	+	+	After coring, remove the cores and follow up with topdressing that fills the holes and leave a sand layer on the top.
2	+	-	+	After coring, topdress with sand and break down the cores, holes are filled with the mixture of sand and soil.
3	+	+	-	Cored and the cores are moved. No topdressing.  Holes are left unfilled. May affect sand percentage.
4	-	-	+	Topdressing only. Case 3 plus case 4 is equivalent to case 1.  Sand increases.
5	+	-	-	After coring we break the cores.  Holes will be filled eventually with same core materials.  No sand increase.
6	-	-	-	No.
7	-	+	+	Not relevant.
8	-	+	-	Not relevant.

 I. Soil-based Medium 

     Sand percentage and impacted area are calculated for the following situations where one practice is repeatedly conducted:

• Case 1: Core, remove cores, and topdress.
• Case 2: Core, don't remove cores, and topdress.
• Case 4: Don't core, topdress only.

      Sand percentage and impacted area can also be estimated when different practice is chosen each time in:

• Case Variable. 

II. Sand-based Medium with a Top Soil Layer 

      Sand percentage and impacted area are calculated for the following situations when one practice is repeatedly conducted:

• Case 1: Core, remove cores, and topdress.
• Case 2: Core, don't remove cores, and topdress.
• Case 4: Don't core, topdress only.

    Sand percentage and impacted area can also be estimated when different practice is chosen each time in:

• Case Variable.