TOP DRESSING

PART 1

Introduction

There are two types of top dressing suitable for application to sports surfaces: either 'origin based' (the same as the soil on the site), or sand based. Each of these dressings is applied for a different purpose. The origin/organic-based top dressing is applied to improve soil nutrients that have been removed during mowing. This type will also aid uneven surface levels.

Sand based top dressing after core aeration can gradually amend a heavy, clay based soil. It can enhance the soil for better drainage and rooting, help to control thatch, and assist in seeding operation.

A professional soil analysis (NPK & pH) of the existing topsoil and proposed top dressing should always be carried out before any application is made. This is normally undertaken by a professional organisation or company who will sample the soil to establish its current condition.

The top dressing should be compatible with the soil in place and will normally consist of a mixture of loam, sand, and organic matter. Any top dressing should be obtained from a reputable source and specifically for sports turf.

If the top dressing is of poor quality it may change the pH and affect grass growth generally. It may also contain pests, diseases and weeds. A representative sample should be obtained for analysis before an order is placed.

SELECTING AN APPROPRIATE TOP DRESSING

The following factors must be considered when choosing a top dressing material:
a. The sport to be played on the surface. For example, applications of light material to a cricket square will destroy the binding properties of the surface.
b. The standard required and how much use is likely to determine the standard and the wear the surface will tolerate
c. Professional advice should be sought on the properties of the existing soil and the type of grass sward present.
d. All top dressing should be obtained from a reputable supplier and prepared especially for sports surfaces. It should be sterile and free from pests, diseases and weeds.
e. pH level should be checked to determine the compatibility with the soil already present.

BENEFITS OF APPLYING TOP DRESSING

a. To replace sand/ soil that is removed or displaced by players and machinery;
b. Thatch control;
c. Smoothing or levelling the surface;
d. Modification of surface soil;
e. Covering stolons or sprigs;
f. Increase Cation Exchange Capacity of the soil; and
g. Improve water infiltration and percolation rates.

TOP DRESSING PROCEDURES

When top dressing apply frequent thin layers usually between 3mm to 10mm with uniform depth. Uneven layers can restrict the flow of water and nutrients into an throw the soil.

Mow the turf to a relatively short height before top dressing, to allow the material to easily reach the surface of the soil. Once the top dressing material has been spread on the surface of the field, drag or brush the field to push the sand into the aeration holes.

Media Department; The RS Group.