MANAGEMENT OF GENERAL EARMS IN OREGON 
15 
RELATION OF LEGUMINOUS CROPS TO CROP YIELDS. 
Table VI shows that the group of silt loam farms having the 
greatest percentage of the field crop area in legumes was operated 
most efficiently. Apparently, therefore, the legumes were profitable 
crops. Aside from being profitable crops themselves, legumes also 
affect the yields of other crops. Table XI shows the influence of 
leguminous crops on the yields of potatoes, wheat, oats, and hay on 
the 144 silt loam farms in 1912. 
Table XI. — Relation of percentage of field-crop area in legumes to crop yields on 144 
farms on silt loam soil, Motion and Polk Counties, Oreg. {1912). 
Item. 
All 
farms. 
No 
legumes. 
Per cent of field crop area in 
legumes. 
Under 18. 18 to 33. Over 33 
Number of farms 
Average percentage of field-crop area in legumes 
Crop yields per acre: 
Potatoes (bushels) 
Wheat (bushels) 
Oats (bushels) 
Hay (tons) : 
Crop index 
144 
20.4 
150.2 
22.0 
37.7 
1.94 
100 
35 
132.8 
18.8 
28.5 
1.82 
83 
37 
12.0 
145.5 
21.5 
38.3 
2.00 
100 
35 
41. 
172.0 
23.8 
40.9 
1.86 
105 
183.5 
23.7 
44.5 
2.07 
111 
There were 35 farms that grew no legumes, 37 that had an average 
of 12 per cent, 37 that had an average of 26 per cent, and 35 that had 
an average of 44.8 per cent of the field-crop area in leguminous crops. 
The yields of potatoes and oats increased steadily, though not in the 
same ratio, as the percentage of the field-crop area in legumes in- 
creased; the yield of wheat of each of the three groups of farms 
growing legumes was considerably higher than that of the 35 farms 
having no legumes; and the groups of farms growing legumes had 
slightly higher yields of hay than did the group having no legumes. 
Crop index, it will be observed, varied from 83 for the group of farms 
having no legumes to 111 for the group having an average of 44.8 
per cent of the field-crop area in legumes. 
Figure 4 is a graphical representation of the percentage of increase 
in the yields of potatoes, wheat, and oats for the three groups of 
farms of Table XI which grew legumes, as compared with the yields 
of these crops for the group of farms having no legumes. It will be 
seen that the percentage of increase in the yields of potatoes and oats 
advanced steadily from group to group, although not proportionally, 
as the percentage of field-crop area in legumes increased; and that the 
percentage of increase in the yield of wheat advanced in the two 
groups of farms having an average of 12 and 26 per cent of the field- 
crop area in legumes and then declined one-half per cent in the next 
group. The yields of wheat, potatoes, and oats for the group of 
farms having an average of 44.8 per cent of the field-crop area in 
legumes were 26, 38, and 56 per cent greater, respectively, than the 
yields of these crops for the group of farms that grew no legumes. 
