Gbe IRatfonal IRurservman. 
FOR GROWERS AND DEALERS IN NURSERY STOCK 
The National Nurseryman Publishing Co., Incorporated 
Vol. XXIX. HATBORO, PENNA., APRIL 1921 No. 4 
A Method of Weeding Seedbeds of Conifer Seedlings by Chemical Means 
All nurserymen realize that weeding seedbeds is an 
everlasting and costly process. The close intermingling 
of weeds and stock seedlings sown broadcast precludes 
the possibility of finding any mechanical labor-saving 
device which would cut down the costs of this operation. 
The use of chemical methods gives promise of success. 
In this connection the experience of the research depart¬ 
ment at the Savenac Nursery of the U. S. Forest Service, 
Haugan, Montana, may be of interest. 
In applying chemical treatment to the soil for the pur¬ 
pose of controlling damping-off, the absence of weeds 
was noticed. Chemical weed eradication has been 
studied in this country and abroad, but the work has been 
largely confined to the killing of plants which have at¬ 
tained considerable size. The possibility of practical soil 
treatments at the time of sowing seemed evident, because 
it is plausible that weaker solutions would suffice to kill 
weeds at the time they first break through and emerge 
from the seed coat. Strong solutions are more deadly, 
but must he ruled out because they are injurious to the 
pine stock being produced. 
The next question was to find a cheap, effective, and 
safe chemical, and determine the proper amount to be 
applied per unit of seed-bed area. Careful work on one 
hundred small plots during 1919 and 1920 was done 
with various strengths of copper sulphate, zinc chloride, 
and zinc sulphate. Lots of 200 seed each of the three 
most troublesome weeds at Savenac,—clover, sorrel, and 
timothy,—were sown in sterilized soil in each plot, to¬ 
gether with 200 seeds of western white pine. Chemicals 
were applied to the soil at the time of sowing. Check 
plots, sterilized and non-sterilized, were left without 
treatment. Results were gaged by comparative germin¬ 
ation (amount, time, and kind), examination of pine 
root tips to determine extent of injury, general thrift, 
etc. 
Treatment with eight grams zinc sulphate in a liter of 
water per square foot of seed bed was chosen as most 
advantageous. 
It succeeded in preventing practically all weed growth 
for two seasons after treatment, tended to stimulate first 
year germination of western white and western yellow 
pine, and apparently did so without appreciable injury 
to the stock.* 
The results seem to indicate that we are on the right 
track—that a solution of the problem is possible and may 
be made practicable. Two seasons is not a long enough 
period upon which to base final conclusions. The next 
step will be to determine the effect this treatment may 
have on the growth of green fertilizer crops used at 
Savenac. If no difficulty is experienced in this connec¬ 
tion, it would seem safe to recommend applicatoin on a 
commercial scale. Stock which has undergone this treat¬ 
ment will he followed at least three years after being set 
in actual field plantations, in order to observe the effects 
of possible internal injuries not now discernible. Com¬ 
plete results on this project are not expected before 1926. 
W. G. Wahlenberg, U. S. Forest Service. 
*It was when the toxic effect on weeds of acid in the soil was ob¬ 
served that the possibility of such chemical methods was first con¬ 
ceived of. Mr. P. C. Kitchin planned and executed the work which 
has given us the results obtained thus far. A continuation of the 
study is being made by his successor at Savenac Nursery. 
A Voice From the “Old Guard 
Every member of the American Association of Nur¬ 
serymen should read the following communication from 
William Pitkin, Rochester, N. Y. 
It is in answer to a letter written by J. R. May hew, 
Waxahachie, Texas, which was published in the March 
issue of the American Nurseryman. Mr. Pitkin, we be¬ 
lieve, voices the opinion of many of the leading nursery¬ 
men, and presents the subject upon which it treats in a 
concise and forceful manner. 
It will enable members of the Association to attend the 
coming convention more fully prepared to adopt a policy 
that will have the support of the whole trade. 
Editor, American Nurseryman:— 
I thoroughly appreciate the honor of being featured in 
your March issue as identified with the Old Guard of the 
A. A. N. If, during my years of membership, I have con¬ 
tributed in a slight degree to the many years of success¬ 
ful, fruitful and harmonious administration of its affairs 
under the regime of the Old Guard, I am abundantly sat¬ 
isfied, and proud to he classed as an humble and retired 
guardsman. 
Perhaps the prominence given me justifies a response 
to your invitation for “a frank statement and a refer¬ 
ence to Mr. Mayhew’s article in the same paper. 
I think you will accept as true my reference to the 
years of harmonious administration—a harmony un¬ 
broken except in a matter of federal legislation when an 
apparent divided sentiment among the members resulted 
in the passage of the law giving the Federal Horticultural 
Board its present far-reaching and arbitrary powers. 
Harmony was the rule and no one loves harmony more, 
or will go farther to secure it, than myself, but I beg to 
suggest that the free use of such expressions as li Re- 
