Soil Functions for any Golf Courses

By Vinod Goyal | Agricare Corporation

The soil is an important factor in the successful establishment of turf grasses. It acts as a reserve for nutrients and water. Air pores assure sufficient oxygen content and promote the breakdown and decomposition processes by microorganisms. The soil material has to be resilient in recovering from the pressures of wear and tear encountered in extreme turf use circumstances.

A. Soil Characteristics and Grass Development

Strong and healthy grass growth with sufficient wear resistance is only possible if a number of soil criteria are met. To assess a turf soil, look at:

  • Particle Size – a good mixture of fine, medium and coarse fractions allows resistance to wear, good base foundation and good drainage.
  • Pores – a well-balanced relation of fine, medium and large pores guarantees regular gas exchange in the soil.
  • Water Permeability – depends on the percentage of large pores.
  • Water Capacity – is defined by the amount of fine and medium pores in the soil.
  • Bulk Density – indicates the degree of compaction and potential root density.
  • PH – is a measure of the acidity/alkalinity of the soil. The availability of nutrients and the activity of nutrients vary according to the pH. Low pH’s severely limit the availability and uptake of nutrients by plants.
  • Cation Exchange Capacity – determined by the mineral and organic colloids. CEC is a measure of a soil’s ability to hold cations. The larger the value of the CEC, the higher the soil’s ability to retain nutrients.

B. Suitability of Soil (Types) for Turf Types

Fertilizer practices vary according to soil type and end use.

For landscape turf one normally simply utilises the existing soil types.

Special soil preparation practises may occur for regularly utilised turf, especially sports turf. Generally speaking, it is necessary to modify the soil characteristics by varying the granular composition, and by mixing in soil conditioners, in order to optimise grass growth, and to attain a high level of resistance to wear.

The graph shows the ideal composition of particle sizes used for sand constructions.

C. Optimum Nutrients Levels in Soil

Specialized constructions based on sand for sports turf and golf greens are characterized by a low capacity to deliver nutrients. The adequate feeding of plants requires all main nutrients such as N, P, K, S, Mg, Ca, etc to be present in soils at sufficient levels.

With regular soil testing (at the start, on a yearly basis; once balanced levels are established, at least every

three years) one can assess the levels of the main nutrients required in order to adopt a fertiliser regime. Optimum levels are given in the table; the higher values represent turf surfaces with high usage. The high N-demand of grasses is satisfied with regular fertiliser application during the vegetative period. Depending on turf type and grass varieties, the necessary N quantities vary from 10 – 40g N/m²/year.

 

D. pH Control

The pH indicates the acidity/alkalinity of the soil sample. It influences grass development, soil structure, bacterial activity, thatch built-up and the availability of nutrients in the soil.

For turf grasses a range of pH 5.5 – 7.3 is acceptable.

Turf grasses for sports fields and golf greens prefer pH levels of 5.8 – 6.5.

Cotula bowling greens’ ideal range is 5.8 – 6.2.

An important thatch-built-up in     Left: Acidifying fertilizer

just a few years.                            Right: Neutral fertilizer

E. Construction of Turf Grounds

Areas for sport fields and golf greens demand high standards. One should carefully check the soil and sand/soil amendments before set up.

  • Turf: Instant turf, or seeded sward if no urgency.
  • Growing medium: Approved sand and soil mix (0.2mm – 0.7mm) 10 – 25 cm deep.
  • Blending layer: Coarse sand or fine grit (0 – 2mm) (2 – 4mm) minimum 5 cm deep.
  • Aggregate: Gravel 8 – 10mm
  • Growing medium: Approved sand and soil mix (0.2mm – 0.7mm) 10 – 25 cm deep.
    Drains: Perforated plastic.

Irrigation systems should be designed and constructed at the same time.