By-Products 159 
and maturity of the crop; but under ordinary conditions 
about one-third, of the total weight of the crop is left as 
tops. This would mean eight tons of tops for sixteen, 
tons of beets. The green weight varies much more than 
the dry weight. Between one and two tons of dry mat- 
ter to the acre in the beet tops can be depended on from 
an average yield of beets, or to put it more definitely, 10 
to 15 per cent of the net weight of the roots. 
Much more has been done to utilize beet pulp than tops ; 
but the tops furnish a cheaper feed than the farmer can 
obtain from any other source. The reason for careless- 
ness in utilizing the tops is probably due to the fact that 
they are a by-product and their true value has been 
underestimated. When dried in the field, beet tops 
contain about the same amount of nutrients as an equal 
weight of alfalfa hay; their feeding value is about the 
same except that they are lower in nitrogen and con- 
tain a comparatively large amount of potash and organic 
acids, which cause animals to scour when they have un- 
limited access to the tops. 
Composition of the tops. 
The composition of tops is shown in Table V. The 
ash consists of potassium, sodium, calcium, magnesium, 
chlorine, sulfuric acid, silica, and phosphoric acid, which 
are valuable fertilizers and should not be taken from the 
land. The tops consist of two to three parts of leaves 
containing about 2.2 per cent ash, to one part of crowns 
containing 5.6 per cent ash. Because of the high ash- 
content of the tops, it is often advocated that they be 
plowed under just as they are topped in order not to 
