20 



BULLETIN 705, U. S. DEPARTMENT OF AGRICULTURE. 



of these farms was not due to the lack of capital or usable land on 

 the part of the clay farms. Neither was it due to the difference in 

 the valuation of real estate on the two types of soil, for Table I 

 shows land was worth $89 per acre on the clay farms and $112 on 

 the silt loam farms. 



CAUSES OF THE DIFFERENCE IN EFFICIENCY. 



(1) An average of 73.6 per cent of the farm area of the silt loam 

 farm, as shown by Table I, was improved land, as compared with 

 71.2 per cent for the clay farms. Thus the silt loam farms have 

 available a slightly higher percentage of improved land. 



(2) The silt loam farms produced clover seed, whereas the clay 

 farms produced none. As shown in Table VIII, clover seed in 1912 

 was a very profitable crop. This contributed materially to the dif- 

 ference in the efficiency of the farms on the two types of soil. 



Table XV. — Relation of types of soil to income per productive animal unit and to crop 

 yield on 212 farms in Marion and Polk Counties, Oreg. (1912). 



Item. 



Salem 

 silt loam. 



Number of farms 



Average income per productive animal unit per farm. 



Average productive animal units per farm 



Crop yields per acre: 



Potatoes (bushels) 



Oats (bushels) 



Wheat (bushels) 



Hay (tons) 



Crop index a 



a Crop index of this table is based upon the 212 records. 



(3) Table XV shows the number of productive animal units per 

 farm, the income per productive animal, and the crop yields on the 

 two types of soil. It will be seen that the clay farms had an average 

 of 13.87 productive animal units per farm, as compared with 13.19 

 for the silt loam farms; and that the income per productive animal 

 unit was $4 greater on the silt loam farms than on the clay farms. 

 This would give the silt loam farms an income approximately $55 

 per farm greater than that of the clay farms. 



(4) From Table XV it will also be seen that potatoes, wheat, and 

 hay,, three of the four leading crops upon which crop index in this 

 table is based, gave higher yields on the clay -farms than on the silt 

 loam farms. Oats, on the other hand, gave the highest yield on the 

 silt loam farms. However, the crop index of the clay farms was 96 

 as compared with 102 for the silt loam farms. The difference in 

 the yield of oats on the two types of soil and the large percentage of 

 the rotation area devoted to that crop (see fig. 1) are the causes of 

 the clay farms having the lower crop index. Hence, the difference 

 in the percentage farm income is of capital on the two types of soil 



