MINERAL COMPOSITION OF SUNFLOWERS GROWN FOR 
SILAGE 1 
By Ray E. Neidig, Chemist , and Robt. S. Synder, Associate Chemist, 
Idaho Agricultural Experiment Station , University of Idaho 
INTRODUCTION 
Sun! wers already have gained an important place among silage 
crops in the Pacific Northwest, chiefly because of their resistance 
to drought and frost and the high tonnage of forage produced per 
acre. Many high yields have been reported. In seasons of abundant 
rainfall 20 tons or more per acre have been obtained, while in seasons 
of deficient moisture approximately 10 tons are obtained. The 
fact that simflowers usually result in high yields of forage per acre 
has given rise to the question by many agriculturists as to the effect 
of sunflowers on the following crop. Repeated observations have 
indicated that crops following sunflowers have been markedly de¬ 
creased. To answer the common query of the farmers, “Do sun¬ 
flowers deplete the soil nutrients?” a study was undertaken by the 
Idaho Agricultural Experiment Station to determine the amount 
of plant foods removed from the soil when sunflowers were grown 
under different systems of plantings. The Maryland station 2 has 
recently reported that sunflowers “draw about as heavily as other 
crops upon the nitrogen of the soil, less heavily than grain upon the 
S orus, and more heavily than other crops upon the potash. 
w to its heavy growth it exhausts unduly the plant food of the 
soil, and should therefore be grown in rotation with other crops.” 
Samples of sunflowers grown at the Idaho station in 1920 under 
different systems of plantings, and harvested at different stages of 
maturity, have been analyzed for their food constituents and the 
results reported in a previous publication. 3 Quantities of each 
sample remained, and these offeree! an excellent opportunity to study 
the mineral content of sunflowers when harvested at different stages 
in their growth and under different systems of planting. For the 
complete plan of the experiment the reader is referred to the former 
publication. 4 
The sunflowers were grown on Palouse silt loam soil, which has the 
following general composition, as determined by Peterson: 5 
Table I .—Composition of Palouse silt loam soil ° 
Si02 
AI 2 O 3 
Fe203 
CaO 
Mgo' 
Na20 
K 2 O 
MAO 
CO 2 
P 2 O 5 
SO 3 
N 
Or¬ 
ganic 
C0 2 
Surface soil_ 
Subsoil... 
67.66 
68.10 
14.90 
14.95 
4.44 
4.48 
2.89 
2.57 
1.31 
1.60 
2.72 
2.76 
1.96 
2.05 
0.0 
0.0 
0.04 
.03 
0.160 
.154 
Trace. 
Trace. 
0.16 
.10 
5.80 
3.45 
• Figures indicate percentages. 
i Received for publication Feb. 5, 1925; issued December 1925. Published by the permission of the 
director as Paper No. 35 of the Idaho Agricultural Experiment Station, 1925. 
► 2 Allen, E. W., Beal, W. H., and Flint, E. R. work and expenditures of the agricultural 
experiment stations, 1922, p. 28, 1924. (U. S. Dept. Agr., Office Exp. Sta.). 
3 Neidig, R. E., and Snyder, R. S. sunflower investigations. Jour. Agr. Research 24:769-780. 
1923. 
* Neidig, R. E., and Snyder, R. S. Op. cit. 
3 Peterson, P. P. soils of latah county, idaho. Idaho Agr. Exp. Sta. Bui. 107, 21 p., illus. 1918. 
Journal of Agricultural Research, Vol. XXXI, No. 12 
Washington, D. C. Dec. 15,1925 
Key No. Idaho-8 
78383—26t-5 
(1165) 
