April 17, 2000
Boy, itís hard to believe that time has gone so fast since the first letter we sent out in December. There are three things that I want to touch base with you on briefly in this letter:
1. USGA changes in physical testing
2. Nitrogen diminishes CEC, University of Wisconsin study shows
3. New bunker test
USGA changes in physical testing
As many of you know, one of the reasons behind the A2L2 certification is to get more consistency between labs. At the national level, the USGA is looking at changing a number of things with regard to physical testing. At a national conference in New Orleans, I became aware of a number of changes that are in the works as far as the physical testing is concerned. Top on the priority list is to eliminate some of the tests currently being run and substituting them with mathematical equations. What the USGA wants to do is to eliminate some of the steps and to take away as much of the variability as possible.
In order to do that, certified labs would need to make significant changes in much of the equipment they now are using.
In particular, this decision affects tension tables: The USGA is thinking of totally eliminating the moisture retention test. (Moisture retention can be mathematically calculated from the sand fractions.) In addition, the USGA will be requesting labs to put the expected rate variation of the test on the report. For example, if your perc test measures 12 inches an hour, in the future the lab will be required to state the expected variation for that test. In this case, it may be +/- 2 inches/hr.
In addition, speaking of perc tests, the USGA is considering making changes in how the tests are run in order to achieve more consistency across laboratories. It has long been known that the moisture percentage of the sand that is submitted to a lab greatly affects the perc rate of the sample. The dryer the sample, the faster the perc rate. Sand companies have known this for a long time, and routinely send their sample to certain labs because they know what kind of results they will get. Now, the USGA will want all sands to be run at a given moisture rate. That may affect turn around time as soil moistures are going to have to be adjusted up or down depending on the moisture content when sent to the lab.
Finally, the USGA is looking at adding a calcium carbonate test. This would tell us how much calcium carbonate is in the sand. For example, if we have sand that measures 5% calcium carbonate, how much lime do we have in 4 million pounds of sand? One acre, twelve inches deep, is equal to 4 million pounds, or roughly the same depth as your root mix.
I talked to Mark Flock, the director at Brookside, to see if we could have that test run as a part of our standard soil tests. It would be a great help to me when we get high calcareous sands that are measuring 85% base saturation for calcium. Mark is looking into it for me and I will get in touch with you when I know the results.
This is a very brief idea of some of the changes that may be coming. These changes would probably be a year and half away.
Nitrogen diminishes CEC, University of Wisconsin study shows
University of Wisconsin soils expert Dr. Phillip Barak recently completed a long-term study of the effects of nitrogen fertilization on soil total cation exchange capacities (CEC). We know that nitrogen has acidifying effects on soils. Barakís research has shown that continued use of nitrogen fertilizers in many soils results in about a 30 to 40% loss of calcium, and a 30 to 40% loss in magnesium. These nutrients we know can be replaced with limes. However, the disturbing part of his research showed that nitrogen fertilizer has a strong negative correlation with regard to cation exchange capacities of the soils, and liming those fields does not bring them back.
The concern in the abstract is that excess use of nitrogen fertilization over time can result in considerable drops in soil cation exchange capacities. Again CEC cannot be brought back by adding ag-lime like some would like to believe. At a rate of 150 lbs/ac, typical CEC losses are from 9 to > 6; 19 to > 12.5. This represents about a 30% drop in soil CEC.
My concern is if this is happening in soils such as our fairways, then what impact is nitrogen having on our USGA greens, where organic matter is very low or non existent, and the CECs of those greens are very low? Iím bringing this to your attention, as this is something that is a big concern to me. If this research is true, it may mean that we may need to be looking more closely at whether the use of organic fertilizers is in the long-term best interest of your soils. As you may recall, we provide total cation exchanges on your soil audits, so we can track them.
New bunker test
The last part of this letter has to do with a new test that is being offered by Brookside. It is called the Bunker Sand Characterization Test. The package includes the following parameters:
Sand, silt & clay, sand fractions, organic matter, color, crusting characteristics, particle shape, ball lie rating, and calcium carbonate equivalent.
In order to run this test, we will need at least one gallon of sand. Turn around time for the test should be about a week.
In my next new letter I would like to touch upon the differences between urea and ammonium sulfate as a source of nitrogen fertilizer. Also, if there is something that you would like me to address, please feel free to e-mail me at email@example.com.
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