778 
Journal of Agricultural Research 
Vol. XXIV. No. 9 
comparison or YIEI.DS, I920 AND 192I 
The yield per acre of sunflowers grown in 1921 was slightly less than 
half the yield secured in 1920, due to dry weather. The total precipitation 
for each month during the growing season is given in the following table: 
Month. 
April 
May. 
June. 
TabliB VI .—Precipitation during the growing season 
1920. 
1921. 
Month. 
1920. 
1921. 
Inches. 
Inches. 
Inches. 
Inches. 
2. 72 
2.86 
July. 
0. 54 
0. 19 
1-35 
I. 80 
August. 
I. 22 
0. 30 
1.16 
1.47 
September. 
2. 52 
• 1.43 
CONCLUSIONS 
A comparison of the results on sunflowers grown in Idaho and those 
grown by Shaw and Walters at Beltsville, Md., shows some striking facts. 
Probably, due to climatic conditions, Shaw and Wright were able to 
secure a more advanced stage of maturity of their sunflower crop as the 
last stage represented the production of good hard seed. As has been 
stated before, it is seldom possible to secure such mature sunflowers in 
certain portions of the Northwest. The crop grown for this experimental 
work is a good example, since the last stage analyzed represents the max¬ 
imum growth. At this period a frost occurred and the sunflowers were 
siloed. 
In content of dry material Idaho sunflowers when siloed represent 
Shaw and Wright sunflowers matured in stages between rays partly 
fallen and rays all fallen. It appears from these results, and results of 
previous years, that the crude protein is considerably higher in sunflowers 
grown in the Palouse country of Idaho than in Maryland, one crop 
grown in 1920 representing 12.38 per cent, and one in 1921 10 per cent, as 
against approximately 7 per cent in Maryland for the same stage of 
maturity. The sunflowers grown in Montana, analyzed by Blish, show 
lower percentages of protein than sunflowers grown in the Palouse section 
of Idaho. From these results it would appear unfair to compare sun¬ 
flowers grown in different parts of the United States for relative food value, 
since the composition of sunflowers may vary widely, owing to the differ¬ 
ences in climatic and soil conditions. 
The 1920 results on the composition of sunflowers at different periods 
of growth show that the crude fiber does not continue to increase as the 
plant passes through the various stages of maturity. Similar results 
were obtained with the 1921 crop. The percentage of crude fiber found 
in the sunflowers cut at the last stage of growth was slightly less than in 
the more immature stages studied. From these data, it appears that there 
is practically no gain in crude fiber during the growth of the sunflower 
plant throughout the five stages of maturity included in this investiga¬ 
tion. The crude fiber may increase materially if the sunflowers are 
allowed to mature completely. At this time the leaves are dead and partly 
fallen and the stalk becomes hard and woody. Silage made from sun¬ 
flowers in this stage of maturity is high in crude fiber and is not palatable. 
It is possible that some of the unfavorable results which have been noted 
in isolated cases with sunflowers have been due to the fact that sunflowers 
were allowed to mature too far before they were cut for silage. 
