TOaSSS? TOW

Issued By The

UNITED STATES GOLF ASSOCIATION GREEN SECTION
P. O. Box 73

Benjamin Franklin Station 
Washington, D. C.

The members of the staffs of the Agricultural Ex­

AGREEMENT ON TURF FERTILIZER: 
periment Stations of Michigan, Ohio, and Indiana, have come to a "gentlemen’s agree­
ment" with fertilizer manufacturers in those states to recommend a 10-6-4 grade of 
fertilizer for general turf purposes. The practical result of this agreement has 
been that 10-6-4 has been placed on the regular price list of standard fertilizers 
and is now available on the market in these states at a price at present in the 
neighborhood of $32.00 a ton. Formerly in these states it was sold as a special 
grade for golf course purposes at two to three times the price at which it is now 
available. Moreover, the consumer is no longer confused by getting recommendations 
for a different grade from each source of information he reaches.

NEW FAIRWAY FERTILIZER SERIES: 
Fertilizers were established in various sections of the country. Some 60 clubs in 
15 different states have already cooperated with the Green Section by establishing 
one of a series of these plots on one of their fairways. In each district in which 
these plots are started it is planned to have at least three series on nearby areas 
so that they will serve as checks under different soil conditions.

Last fall a number of series of tests on Fairway

Additional series are being established this spring. Most of them 

will be maintained under playing conditions on golf courses, but some will be on 
lawns in parks and elsewhere as well as on various types of recreational areas. It 
is also p~l armed to include in this program tests on turf on road shoulders and land­
ing fields.

Each series consists of twelve 10 by 30-foot plots on which different 

ratios of nitrogen, phosphoric acid, and potash are applied in both organic and in­
organic forms, with and without lime. Results are to be followed over a period of 
years.

This probably is the most extensive series of fertilizer tests ever 

run on established turf. If you are interested in the program and do not have a 
series of plots in your neighborhood, we shall be glad to have you write the Green 
Section’s office for further details.

Certain strains of creeping bent tend to produce an ex­

REMOVE EXCESS STOLONS: 
cess of stolons on the surface during the spring months when growth is particu­
larly vigorous. When not removed or covered with topdressing, these stolons cause 
objectionable grain in the turf during the summer months. Perhaps the best way to 
remove them is to give the turf a severe raking or brushing followed by close mow­
ing. This should be done not later than the middle of May while the grass is grow­
ing vigorously enough to cover up the scars quickly. Light brushings may be given 
throughout the summer months.

USEFULNESS OF EXPERIMENTAL GREENS: 
as being unusually severe this year in some sections of the country. If the 
disease is prevalent in your neighborhood you may find it of interest to visit the 
Green Section Experimental Green in your district and observe which of the strains 
being tested there are particularly resistant to this disease.

Injury from snowmold has already been reported

April 1941

In those regions in the South which experienced frosts

TURF IN THE SOUTH: 
this winter, it may be found that the Bermuda grass has been injured. The 
injury is likely to be most severe on areas where the turf is cut close, such as 
putting greens and tees. In such areas recovery may be hastened by light disking 
with the disks set as straight as possible, followed by dragging with a brush 
harrow or other smoothing device and then rolling. An early application of 
fertilizer will also be helpful in thickening the grass where injury was not 
sufficient to necessitate reseeding. Sulfate of ammonia will often stimulate 
a quick growth of Bermuda grass in spite of some cool weather. Where injury is 
severe, reseeding may be necessary.

Greenkeepers who have winter greens should watch their ryegrass for 
any signs of brownpatch. The prompt use of mercury fungicides will retain the win­
ter grasses in good condition for a longer time, thereby giving the Bermuda grass a 
chance to produce a good new growth before the summer greens are opened for play.

LATE WINTER DROUGHTS: The Weather Bureau reports that scanty precipitation in 
recent months has resulted in rather serious dryness in the Ohio and lower Mis­
souri River valleys. Some areas in the Ohio valley report the driest January, 
February and March-period on record. A dry period during this time of year may 
actually be of benefit to turf if it is followed by more rain later in the season. 
Spring root development is better in soils which are not saturated as they usually 
are during this season of the year. Because of this lack of precipitation, the 
surface soil may appear dry and the temptation may be to water early, but this 
should be postponed until it is actually necessary.

TRIPS OF GREEN SECTION STAFF: Dr. Monteith plans to be in New England early in 
May, when he is to represent the Green Section on the program of the May meeting 
of the Greenkeepers of New England. This meeting will be held at the Ponkapoag 
Golf Club in Canton, Massachusetts, on Monday, May 5, beginning at 10:00 A.M. 
Any clubs in that area which are planning to ask for visits from the Green Section 
staff would do well to plan for them at that time and correspond with Dr. Monteith 
as soon as possible to arrange for dates. Those who attend the meeting at Ponkapoag 
will no doubt be interested in observing and rating the twelve strains of grass on 
the experimental green which was established there two years ago in cooperation with 
the Green Section.

SOIL ACIDITY

The acidity of soil solution, as of any other watery solution is 

caused by what the chemist terms hydrogen (H) ions, and the alkalinity by hydroxyl 
(OH) ions. Chemically pure water contains an equal number of hydrogen and hydroxyl 
ions and therefore is neither acid nor alkaline but is referred to as being neutral. 
When any other chemical is present in solution even in exceedingly small quantities 
the ratio between the numbers of hydrogen and hydroxyl ions is changed. The product 
of the concentrations of these two ions remains the same, however, and therefore as 
the number of hydrogen ions is increased, the number of hydroxyl ions is decreased, 
and vice versa. When there is an excess of hydrogen ions, the solution is said to 
be acid and the greater the excess the greater the acidity. When the hydroxyl ions 
are in excess the solution is alkaline and the greater the excess of them the greater 
the alkalinity.

One liter (approximately one quart) of chemically pure water or any 
neutral solution contains 1/10,000,000 of a gram of hydrogen ions. Fractions with 
such large denominators make the expression of the actual concentration of hydrogen 
ions a cumbersome matter. Consequently, acidity and alkalinity are referred to 
in terms of small whole numbers which refer to the number of ciphers in the denomi­
nator of these fractions. These numbers are arranged on a scale which is known as 
the pH (pressure of hydrogen) scale.

April 1941

T. T. T. 2

On the pH scale the figures run from 0 to 14, with the midpoint 7 
referring to 1/10,000,000 gram which is the weight of hydrogen ions in a neutral 
solution. The values pH 3, 5, and 9, for instance, refer to 1/1,000, 1/100,000, and 
1/1,000,000,000 gram of hydrogen respectively. Thus the numbers less than 7 refer to 
acid solutions and the numbers greater than 7 to alkaline solutions. At pH 6, 5, 
and 4, the acidity or the concentration of hydrogen ions is 10, 100, and 1,000 times 
greater than at pH 7. On the other hand at pH 8, 9, and 10, the alkalinity or the 
concentration of hydroxyl ions is 10, 100, and 1,000 times greater respectively, or 
the concentration of hydrogen ions 1/10, 1/100, and 1/1,000 times as great respective­
ly as at pH 7.

The pH values of arable soils normally fall between 4 and 9 but the 

great majority of surface soils under cultivation have pH values between 5.0 and 
7.5. Plant life in general, including many of the fungi, appears to be stimulated 
by a moderate excess of hydrogen ions. Moreover, there is a wider tolerance of ex­
cessive acidity than of excessive alkalinity. In higher plants, this may be asso­
ciated with the fact that the pH of the cell sap in the roots of most plants ranges 
between pH 4 and 6. It would seem, therefore, that soil acidity should be regulated 
rather than eliminated.

In a broad way, plants are able to adjust themselves to a considerable 

range of pH, although a few crop plants such as alfalfa, red clover, sugar beets, 
sorghum, tobacco, cabbage, and cauliflower are extremely sensitive to an acid condi­
tion, whereas other plants, such as cranberries, blueberries, coffee, pineapple, 
holly, rhododendrons, and azaleas prefer a distinctly acid condition, growing well 
in soils with an acidity of pH 4.0. The turf grasses, fortunately fall in the much 
larger group of plants which tolerates a wide range of acidity. In some of the 
Green Section’s experiments in various sections of the country, good turf of both 
bluegrass and bent has been produced over a period of 5 years on soils which ranged 
from pH 4.7 to 7.5 when they were properly fertilized. (See TURF CULTURE, December, 
1939.)

The acidity of the soil also affects the growth of soil fungi and 

bacteria. The fungi causing many plant diseases thrive in a rather limited range 
of pH. Some twelve years ago, for instance, it was demonstrated by the Green 
Section that the severity of dollarspot, brownpatch, and soald on bent turf grow­
ing on very acid soil was significantly reduced by the addition of lime. The 
nitrogen-fixing bacteria in alfalfa, on the other hand, do not thrive at a soil pH 
lower than 6.5. In too acid soils also, the bacterial decomposition of organic matter 
is retarded and consequently insufficient amounts of nitrogen are released for growth 
of higher plants.

There are numerous other indirect effects of the acidity of soil on 

its fertility. The physical characteristics of clay soils are unfavorably affected 
by an acid condition, the presence of calcium being necessary for the desirable 
crumb structure of soil. Also, the availability of nutrients such as phosphorus, 
iron, and others are decidedly influenced by the acidity of the soil solution.

The benefits derived from the use of lime, however, are not neces­

sarily consistent with the pH values of soil. Lime may be present to such an 
extent as to supply plenty of active calcium, without greatly reducing the acidity 
and, on the other hand, soils may have a pH of between 6.5 and 7.0 and still not 
have enough active calcium for good growth of plants. For example, in the Green 
Section’s fertilizer experiments mentioned above, the turf on the most acid soils 
did not necessarily respond better to applications of lime than did the less acid 
plots. The most beneficial results were produced on an almost neutral soil of pH 
6. 7, whereas, in another area with a soil pH of 6. 7, the turf on the lime-treated 
soil was poorer than that on the untreated soil. The second best results from the 
application of lime were obtained on an acid soil of pH 4.7.

It is evident, therefore, that the simple determination of soil pH, 
although a useful guide, does not furnish sufficient information to form the basis 
for dependable recommendations for the application of lime or fertilizers. Snail 
scale field tests based on the results of laboratory soil tests, should give 
more reliable information as to the treatment required.

April 1941

T. T. T. 3