Hollow-tining is that time of the year when you find lots of regular-sized holes and lots, lots more irregular-sized sand on the greens. It’s the time when you wish you were somewhere else but on the green. “Aiyah, why do today, next week cannot ah?”

Hollow tine holes filled with sand.

I’ll attempt to tell you why this is a necessary process on a golf course. It has something to do with what is called “Compaction”. There are two ways to explain compaction.

1. Compaction occurs whenever a compactive event squeezes soil. It’s squeezed into a smaller volume by eliminating some pore space that interspersed naturally between soil particles therefore increasing the density of the soil. Or,
2. Compaction is when a load is more than what a soil can absorb

Golfers, buggies, mowers, sprayers or traffic of any nature can ensure compaction. Actually, any load on soil can become a compactive event under the right conditions. The effect of a load on soil depends on the weight, the size of the area supporting the load and soil conditions.

When they say “soil”, what you see is probably the turf or maybe the sand or clay beneath the turf. But try imagining it if we magnify it a thousand times. The “soil” would consist of lots of tiny particles with space in between them. Like when you see large rocks piled on top of each other, in between the rocks you see spaces, right? Same-lah! Except that it is tiny. Clay is even tinier than sand. Tiny-tiny.

And when we say “compaction”, what we means is that whatever is on top of the soil is squeezing the particles closer together and making the spaces smaller and smaller. The particles remain the same size, just the space become smaller. The air comes out of the spaces.

Compacting creates complex relationships that permeate through numerous soil properties. Deterioration of turfgrass may not be seen until one of these properties becomes limiting in the total turf environment. Compaction will have a bad effect on physical, chemical, water or biological condition. This will cause the poor superintendent to run around curing “diseases” and treating “problems” when the actual problem is compaction.

This is what happens

When air is squeezed out of the space, there will come a time when oxygen will be deficient in the soil atmosphere. Under low oxygen conditions, turf will stress and become more sensitive to attack by certain disease organisms. At the same time, low oxygen can also kill organism that is good for turf. If the organism that attacks the turf is fungi, we can spray fungicide and kill it, but we are treating the symptom and not the cause. Symptom: Disease Causes: Compaction.

Did I mention that a heavy load doesn’t always cause more compaction than a light load? A light load on a wet enough soil can cause more compaction than a heavy load on dry soil. That’s why we’re not encouraged to drive buggies into the fairways or rough when it’s wet; even we think we’re not leaving tracks.

To make a long and technical story short, compaction affects turfgrass growth in many ways and unfortunately they’re not always consistent. Compaction’s main effects which can be observed will be:

a)   Root growth ; root development will decline in compacted soils. This may be measurable by root mass, extension rate or density,

b)   Shoot growth ; a decline in visible turf quality that will develop slowly and can last for a long time,

c)    Nutrient relations : Nutrient uptake is an aerobic (need oxygen) process. While compaction is a physical process, the reduced aeration it causes can affect chemical and physiological processes that ultimately impact turf nutrition.

d)   Water relations: Depending on conditions, compaction can cause the soil water content to be too much or too little. Both conditions limit turfgrass growth, either because of not enough water or too much water.

So How?

Many forms of mechanical management are available to reduce the effect of compaction by introducing large openings. These approaches can reduce bulk density. But to be effective the macropores must be open to the soil surface. Which is why the Hydroject is not always effective (but that’s another story).

So we core, we use coring machines. We attach “tines” to the machines. There are two types of tines; hollow tines and solid tines. Hollow tines are preferred because they pull up the cores or plugs. Solid tines will simply punch them in, in some cases causing compaction deeper in the soil. The tines sizes will vary between a quarter of an inch to an inch, depending on the type of area, the requirement of the soil profile and the frequency of the renovation. The lesser the frequency, the bigger the tine. (No kidding).

We can also spike. It relieves compaction to a certain extent. It also allows for improved water penetration. But it is not very effective on heavily thatched areas.

Slicing can be carried out on a regular basis for problem areas. It is a short term cure to relieve heat stress, encourage new rot and shoot growth and increase water infiltration.

Water (or air) injection is a relatively new concept. It involves forcing water (or air or materials like Styrofoam) into the soil profile at high pressure. It is ideal for older greens, especially soil profiles that have high clay content or with the “layering effect”. It is also ideal for greens with high traffic, because the penetration point at the surface is tiny and almost unseen.

Verti-drain® can be similar to coring, the difference being, the verti-drain can go deeper. It has been designed to allow the change of poor soil profile. It can be used on greens where the thatch layer is quite thick.  The Verti-drain  can be fitted with hollow tines for coring just like ordinary hollow tines but deeper. Or it can be fitted with long, small solid tines that combined with a built in action of the machine, creates a crack in the soil as the tine is pulled up. You can adjust the size of the crack by adjusting the angle of tine being pulled out of the ground. Quite useful because of the depth it can go in and that the hole in the surface can be as small as a few millimeters.

Drilling is very deep hollow-tining. (Up to 20 inches). This process is very slow although it would give a very quick result.

And there you have it, some of the ways to relieve compaction on the golf course. So the next you make that one putt for a birdie and  feel like jumping up and down with joy, think….Am I part of the compactive event that squeezes soil solids into a smaller volume by eliminating some pore space that interspersed naturally between soil particles therefore increasing the density of the soil?

See you next time.

Reference:

Thien, Steve J, PhD, 1994, Compaction’s effect on soil biological processes, Golf Course Management. GCSAA.

Fuller, Kym, 1994, Renovation of Turf, ASEAN Plant Quarantine Centre and Training Institute.

Whittle, Chris, (nodate). Basic Greenkeeping Principles, The Care and Maintenance of Recreational Playing Surfaces. SISIS Equipment, Cheshire.