THE RELATION OF SULPHUR TO ALFALFA PRODUCTION 1 
By Oscar C. Bruce 2 
Department of Agronomy , Kansas State Agricultural College 
INTRODUCTION 
That sulphur is one of the essential 
elements for the proper growth and 
development of plants is a well-known 
fact. Being a constituent of most 
proteins which are closely associated 
with living matter, it probably is 
connected with physiological processes 
in the formation of compounds which 
do not contain sulphur. If this be 
true, it is apparent that sufficient 
quantities of sulphur must be supplied 
to plants in order to produce normal 
maximum growth. 
In recent years the importance of 
sulphur in crop production has been 
given greater consideration than for¬ 
merly. Probably this is due to the 
early and erroneous methods of analy¬ 
sis which indicated that crops removed 
very small amounts of this element 
from the soil. Hence it was thought 
that if crop residues were returned, 
most soils contained enough sulphur 
to produce maximum yields indefi¬ 
nitely. However, improved methods 
of analysis have shown that consider¬ 
ably more sulphur is removed by plants 
than was formerly thought to be the 
case and that in some instances it may 
be the limiting factor in crop produc¬ 
tion. 
In field experiments sulphur defi¬ 
ciency has been observed most fre¬ 
quently with legumes. Since alfalfa is 
one of the most important legumes, it 
was deemed desirable to investigate the 
possibility of increasing the yields of 
this crop by sulphur fertilization. 
This paper reports 10 results of a single 
experiment conducted for one season. 
REVIEW OF LITERATURE 
Reimer and Tartar (13) 3 in Oregon 
found that the yields of alfalfa and red 
clover can be greatly increased by the 
use of sulphur-containing fertilizers. 
The soils on which these experiments 
were conducted contained only limited 
amounts of sulphur. Superphosphate 
and gypsum were found to increase 
the yield of alfalfa and produced a 
darker green color, while rock phos¬ 
phate had little or no effect whatever. 
Other sulphur-containing fertilizers in¬ 
creased the yields from 50 to 1,000 per 
cent, larger increases being obtained 
in some cases than in others where the 
same amount of sulphur was applied. 
These differences were attributed to 
differences in depth and physical con¬ 
dition of the soil. The application of 
fertilizers containing nitrogen, phos¬ 
phorus, and potassium had little or 
no effect on alfalfa. The same was 
true regarding the application of lime. 
This was taken to indicate that any 
benefits derived from sulphur-contain¬ 
ing fertilizers could not be due to their 
effect upon liberating phosphorus, 
potassium, or lime in the soil, or upon 
nitrification. The root system and the 
number of nodules was also materially 
increased by the addition of sulphur. 
Plants receiving sulphur contained 
more nitrogen and more protein than 
those from the control plots. 
Fellers (5) secured a material increase 
in the yield of total dry matter and 
seed of soy beans by small applications 
of acid phosphate on well limed soils. 
Small applications seemed to be as 
effective as larger amounts. It was 
observed also that acid phosphate 
applied on limed soil increased the 
nodule development and content of 
oil. Protein formation was benefited 
on both limed and unlimed soils. Land 
plaster produced but little effect unless 
applied in large amounts, in which case 
the oil content of the seed and the 
growth of nodules were stimulated. 
Applications of elemental sulphur in 
small amounts, not over 100 pounds 
1 Received for publication July 29, 1924; issued July, 1925. Contribution No. 152, Department of 
Agronomy. Kansas Agricultural Experiment Station. Although this paper reports the results of 
but a single experiment conducted for one season, it is thought desirable to publish the results for the 
benefit of other workers, since there is no immediate prospect of continuing the work. 
2 Professor of Soils, College of Agriculture, University of Maryland; Associate in Soil Survey, Mary¬ 
land Agricultural Experiment Station; Fellow, Sulphur Fellowship, National Research Council, Kansas 
Agricultural Experiment Station, 1922-23. 
3 Reference is made by number (italic) to “Literature cited,” p. 947. 
Journal of Agricultural Research 
Washington, D. C. 
( 937 ) 
Vol. XXX, No. 10 
May 15, 1925 
Key No. Kan. 45 
