84 DRY-FARMING 



downward; though under conditions that are not 

 favorable for the downward penetration of the roots 

 the lateral extensions may be very large and near the 

 surface (Figs. 22, 23). 



Extent of roots 



A number of investigators have attempted to 

 determine the weight of the roots as compared 

 with the weight of the plant above ground, but the 

 subject, because of its great experimental difficul- 

 ties, has not been very accurately explained. Schu- 

 macher, experimenting about 1867, found that the 

 roots of a well-established field of clover weighed as 

 much as the total we ght of the stems and leaves of 

 the year's cro]3, and that the weight of roots of an 

 oat crop was 4.3 per cent of the total weight of seed 

 and straw. N(jbbe, a few years later, found in one 

 of his experiments that the roots of timothy weighed 

 31 per cent of the weight of the hay. Hosseus, 

 investigating the same sul)ject al)out the same time, 

 found that the weight of roots of one of the brome 

 grasses was as great as the weight of the part above 

 ground ; of serradella, 77 per cent ; of flax, 34 per cent ; 

 of oats, 14 i)er cent; of barley, 13 per cent, and of 

 peas, 9 per cent. Sanborn, working at the Utah 

 Station in 1893, found results very much the same. 



Although these results are not concordant, they 

 show that the weight of the roots is considerable, 



