FieldScience | ByJim Hermann, CSFM
Selecting the right topdressing material
job. Soils can vary from very fine, heavy textured clayey soils to very coarse; light textured sandy soils, depending on the loca- tion. Therefore, the same topdressing mate- rial may have different results on different locations. It is important to know the texture of the soil in your rootzone, so start by ob- taining a physical analysis of your soil by a reputable testing laboratory. In addition to the proportions of sand, silt and clay in a soil, the coarseness or fineness of the sand portion, has an effect on the physical
I
N ORDER TO HAVE A SUC- CESSFUL TOPDRESSING PRO- GRAM, it is essential to choose the right topdressing material for the
properties of a specific classification of soil.
sistent particle size usually has a higher rate of hydraulic conductivity than a material containing a more diverse blend of coarse, medium and fine particles. A principle to remember: water will move from a coarser textured soil to a finer textured soil more readily than the other way around, provid- ing there is adequate pore space between the particles.
Medium size sand with a relatively con-
existing rootzone, adequate cultivation is necessary to insure proper incorporation of the material. The more a topdressing mate- rial varies from the existing rootzone in re-
When using any material to modify an
lation to its texture classification and physi- cal properties, the more cultivation is typi- cally needed. Without adequate cultivation there re-
mains a very real potential for layering in the soil. Anytime there is a layer created in the soil, the interface between the layers will have the potential to negatively affect
A few reasons for topdressing are:
Modification of existing rootzone. • Increase water conductivity • Increase organic matter content • Increase tilth (soil structure) • Increase cation exchange capacity (CEC)
Increase success rate of renova- tion thru improved soil seed con- tact.
Smooth a rough uneven surface.
16 SportsTurf | June 2012
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