8 BULLETIN 1471, U. S. DEPARTMENT OF AGRICULTURE 
CONDITIONS WHICH CAUSE OIL CONTENT OF FLAXSEED TO VARY 
CLIMATIC CONDITIONS 
From an examination of numerous plants with respect to oil 
content and composition it has been found that the nature and the 
quantity of the oil in the plant is influenced by climatic and soil 
conditions. The conditions vary in different localities. The ex- 
tremes and means act either in facilitating or retarding the growth 
of plants, and therefore affect favorably or unfavorably the forma- 
tion of oil in the seeds. 
The availability of the plant food in soils is due to a large extent 
to the amount of moisture present, which in turn is dependent upon 
certain other conditions, such as heat, light, humidity, and altitude. 
Retention of moisture by some soils and lack of retention by others 
naturally affect the growth and development of the plant and the 
formation of oil in the plant. 
Any cause which tends to modify the growth or nutrition of a 
plant has a material effect upon the formation of oil in the seed. 
This has been brought out by the work of Garner, Allard, and 
Foubert (.£), Pigulevskii (5), Rabak (7), and others. 
The amount of precipitation during the growing season is one of 
the most influential factors affecting the oil content, of flaxseed, since 
the proper growth and maturity of the flax plants are dependent 
largely upon the amount of moisture available. 
In North Dakota the average annual precipitation ranges from 
about 23 inches in southwestern counties to about 14 inches in cer- 
tain areas in the western part of the State. Local rains, especially 
during the critical growing period of the crop, should influence the 
oil content of the seed. In Table 4 is a comparison of the oil content 
of the flaxseed grown in North Dakota with flaxseed grown in areas 
having the indicated inches of rainfall. Drawing conclusions on the 
basis of averages, there is a rather decided relation between the 
inches of rainfall and the percentage of oil in flaxseed. The seed 
grown in areas having 15 to 16 inches of rain contained the highest 
percentage of oil. The percentage of oil in the samples became 
progressively smaller as the moisture increased up to and including 
23 inches of rainfall. 
Table 4. 
-Influence of total rainfall hi North Dakota on oil content of flaxseed, 
crop of 1923 
Number of samples 
Average percentage of oil. . 
Maximum percentage of oil 
Minimum percentage of oil 
Range in percentage of oiL. 
14 to 15 15 to 16 16 to 18 18 to 20 20 to 23 
3 
41.47 
41.81 
40.81 
1.00 
Rainfall (inches for the year) 
87 
42.41 
44. 33 
39. 09 
5.24 
115 
41. 04 
43. 94 
37.12 
6.82 
95 
40. 91 
43.13 
31.28 
11.85 
47 
40.40 
43.29 
38.76 
4.53 
