You walk through the door of the doctor's surgery and, without looking up from his desk, he throws a bottle of pills at you and says, "Take these and you'll be better soon". Or, you visit a different practice, go into the surgery, he asks you to sit down and tell him what your problems are, and what your expectations are. He then examines you, takes samples, does a few tests, and asks you to call back in a week so that he can discuss the results with you.
Without exception everyone reading this will say that they would believe the second doctor. Well, doesn't your turf deserve the same care?
When a salesman calls do you take the first 'medicine' that he shows you from his catalogue or do you have a fertiliser salesman who will discuss your objectives? What standards do your members expect? Do they give you a budget that relates to their expectation? Do you have specific events that you and your members want the facility to peak for? Then, suggest soil samples should be taken. If your own health deserves the doctor who cares, then so does the health of your turf.
When I visit a new venue, wherever in the world it is, I like to take the soil samples with the Turf Manager. It gives me the opportunity to get to know him, and him the opportunity to tell me about his turf, his members, his staff levels and all the other issues that confront a turf manager every day. It also provides me with the opportunity of finding out how I can be as helpful as possible.
Amongst other things I note the grass varieties, I notice how well the site drains, these two aspects are essential when it comes to making the correct recommendations. Different grasses require differing nutritional programmes and, whilst good drainage is great for the members, it generally means that the nutrients leach quicker than on a site with poor drainage.
It should also be remembered that the better the sampling the better the report, and then, the more accurate the recommendations. The sample should be taken to a depth of approximately one inch below the current depth of the roots. There is no point in testing down to two feet when the roots are only two inches deep. The turf is not going to be affected by any nutritional imbalance a distance away from the root hairs.
Recent research by Yara Phosyn has demonstrated that nutrients can only be drawn the following distances - phosphorus 1mm, magnesium 5mm, potassium 7.5mm and nitrogen 20mm.
The samples on a golf green should be taken at five points; I like to take them in the shape of a five on a dice, on larger areas the principal is the same, take the samples from evenly spaced locations around the site.
For testing I remove the turf from the top of the plug. The reason I do this is because we want to measure the organic content of the soil, this measurement can be affected by grass left on the top of the soil. The five samples from each green or pitch should then be mixed to give a representative sample of the whole area.
An often-asked question is when should I take the samples? The ideal is just prior to the application of fertiliser; the reason is that a recent application of fertiliser will give an incorrect indication of what is going on in your rootzone. An obvious point; never forget to clearly label the samples!! The best testing in the world is no good if you don't know where the sample came from!
The samples should be tested for pH, organic matter, the three primary nutrients (NPK), the three secondary nutrients (Ca,Mg,S) and trace elements zinc, manganese, copper, iron and boron. It has been accepted for many years that excesses of nutrients will lock up other nutrients (chart 1), so an excess of manganese will lock up your phosphorus and your potassium thereby affecting your root development and plant health.
If you don't test for manganese you would not be aware of this, and would then make incorrect decisions which may include the application of additional phosphorus, not realising that the reason for the poor root development is not a shortage of phosphorus but rather that it is locked up. The continued application of this phosphorus could then, if it continued, lock up calcium, magnesium, zinc, manganese, copper and iron. So, it is important to test all the nutrients that have a bearing on the other nutrients.
When the results (chart 2) are returned from the laboratory, I believe that the Turf Manager should receive a copy of the exact figures. Managing turf is a mix of art and science, and there is no target for any nutrient. On a sandy rootzone one turf manager may feel that a phosphorus level of sixteen is low, another could think it was high and a third may feel that it is ideal. For this reason you should see the figures and not just the fertiliser salesman's opinion.
With experience you can identify more and more from soil results and this can be massively helpful. We recently received soil test results from polo fields in The United Arab Emirates. We were able to identify a very high risk of developing black layer on one of the fields and suggested further tests and a programme designed to flush the excess sulphur. The Turf Manager was delighted that we could identify a problem at distance, and he was able to cure the problem and achieved a remarkable improvement in the quality of his turf.
Another figure on a soil report is cec, this is an abbreviation of cation exchange capacity and is a very good indicator of how much nutrient a soil will retain.
Typically, a sandy soil will have a cec of four to six, with a high clay or organic soil having a cec of up to twenty, so the sandy soil will drain better but the clay soil, with a high organic content, will hold more nutrient.
One thing that is frequently misunderstood is that cec is not measured, it is in fact calculated, the calculation is:
- Calcium parts per million divided by 200 added to
- Magnesium parts per million divided by 120 added to
- Potassium parts per million divided by 390 added to
- Sodium parts per million divided by 240
This will give the cec.
The laboratory report should come back with a pre-calculated cec, but it is important that the Turf Manager understands that this has not been measured but rather calculated, and a heavy application of fertiliser prior to testing will make the cec appear artificially high.
I frequently get asked what is the ideal cec. The answer is that there is not an ideal level, just the one that you have. It is important to work with this rather than against it. If you have a low cec, there is no point in applying large amounts of nutrients in a single application. It is better to apply little and often, otherwise you will leach most of the nutrient, which is bad for both your budget and the environment.
Having obtained the results, and decided which nutrients are in excess and which are in deficiency, it is then the task of the fertiliser supplier and the Turf Manager together to balance all the nutrients.
The way I look at it is, an athlete is strong and resists illness and injury but, when injured, recovers quickly; a big factor in this is that an athlete eats a balanced diet. Your turf should be able to fight off disease and recover quickly from damage however caused. To do this your plant needs a balanced diet. So, you should balance the nutrients in your rootzone. You cannot do this if you don't know what is in the rootzone when you start.
Once you know your starting point you can provide what is deficient and avoid what is in excess. Your nitrogen, phosphorus and potassium are the plants meat and two veg but, remember, that the plant needs all the other secondary and trace elements, just as the athlete needs his multi vitamins. Trust the doctor who cares enough to do the tests.
Author: Richard Lawrence
Environmental Turf Technology Ltd.
Tel: 01524 381999