THE EFFECT OF SULPHUR AND GYPSUM ON THE 
FERTILITY ELEMENTS OF PALOUSE SILT LOAM 1 
By Lewis W. Erdman 2 
Washington Agricultural Experiment Station 
INTRODUCTION 
During the past few years some soils 
have been found to be quite low in 
total sulphur, and the use of sulphur as 
a fertilizer has been suggested as a 
means of remedying this condition. 
Most of the experiments with sulphur 
have had certain objects in view: (1) 
To study its effect on the growth and 
composition of crops; (2) to determine 
its effectiveness when inoculated with 
sulphur-oxidizing bacteria and com¬ 
posted with manure and rock phos¬ 
phate in rendering available the phos¬ 
phorus in the rock phosphate; and (3) 
to determine its effectiveness when 
composted with manure and greensand, 
in making the potassium in the green¬ 
sand available for crops. Very little 
attention has been given to the direct 
effect of sulphur on the fertility ele¬ 
ments in the soil. From the soil fer¬ 
tility point of view, this problem is of 
unusual significance, because the future 
value of sulphur as a fertilizer will 
depend not only upon its ability to 
increase crop growth, but also upon the 
reactions which it brings about in the 
soil, and especially upon its effects on 
those elements which have a direct 
bearing on fertility. 
The present investigation was planned 
to ascertain to what extent the sulphur, 
potassium, phosphorus, nitrogen, cal¬ 
cium, and magnesium of the Palouse 
silt loam, an important soil type in 
Washington, are affected by appli¬ 
cations of uninoculated sulphur, in¬ 
oculated sulphur, and gypsum. 
EXPERIMENTAL WORK 
The soil used was a typical Palouse 
silt loam secured from an alfalfa pas¬ 
ture on the experimental farm of the 
State College of Washington. Wheat 
is grown extensively on this particular 
soil. It is derived mainly from basaltic 
rock and, judging from the following 
chemical analysis, may be considered of 
good fertility. 
Pounds per 2,000,000 pounds of soil: 
Nitrogen, 2,900; phosphorus, 1,280; po¬ 
tassium, 42,400; sulphur, 960; calcium, 
29,200; magnesium, 20,200. 
Twenty-four ordinary clay flower¬ 
pots (inside diameter at top 12 inches, 
at bottom 8.75 inches, and depth 8.5 
inches) were used for this work. These 
were divided into two series of 12 each, 
the first series being used for experi¬ 
ment 1, and the other for experiment 2. 
Each pot was thoroughly paraffined on 
the inside, and in the bottom was 
placed a paraffined cork stopper 
through which a short glass tube was 
inserted to permit the removal of 
drainage water. The outlet of the 
tube was covered with a very small in¬ 
verted clay pot to prevent the soil 
from clogging the opening. 
EXPERIMENT 1 
In an open field on the college farm 
a stand was built large enough to hold 
12 pots and just high enough to allow 
2.25-liter acid bottles to be placed 
beneath. The glass tube leading from 
each pot entered one of these bottles, 
the mouth of which was covered to ex¬ 
clude rain and dust particles. On 
November 27, 1922, 18^ lbs. of soil 
(moisture-free basis) was placed in each 
pot. This amount of soil approxi¬ 
mated the ordinary depth of surface 
soil (6% inches). The following treat¬ 
ments, made in duplicate, were 
thoroughly mixed in the upper 2 inches 
of soil on December 5, 1922. 
1 Received for publication June 17, 1924; issued May, 1925. Published with the approval of the director 
of the Washington Agricultural Experiment Station as Scientific Paper No. 109. The work reported in 
this paper was done in the laboratories of the Division of Chemistry of the Washington station under the 
a Formerly research fellow, National Research Council Sulphur Fellowship. Now assistant professor of 
soils and assistant chief in soil bacteriology, Iowa State College. The writer wishes to acknowledge his 
indebtedness to the Sulphur Fellowship Committee of the National Research Council for the appoint¬ 
ment to this fellowship; to Dr. J. R. Neller for many helpful suggestions; and to Dr. P. E. Brown for 
reading the manuscript. 
Journal of Agricultural Research, 
Washington, D. C. 
( 451 ) 
Vol. XXX, No. 5 
Mar. 1,1925 
Key No. Wash-3. 
