78 The Sugar-Beet in America 
While applying nitrogen in a form to encourage steady 
and continuous growth would result in a large yield, it 
would also produce beets low in sugar. In order to en- 
courage the desirable early growth, nitrogen should be 
supplied largely in the readily available form in the 
spring before planting; organic, or slow-acting, forms 
should not be applied at that time. 
When beets are raised for stock feed, fertilizing should 
be done in such a way that rapid and continuous growth 
is secured. This is accomplished by large applications of 
nitrogen and phosphoric acid throughout the season, 
especially the former. The liberal use of farm manure 
would be desirable in this connection, especially on heavy 
soils. On light soils all the fertilizer elements could be 
supplied as commercial fertilizers. 
A discussion of the sources of the various fertilizer 
elements follows. 
Nitrogen. 
The most expensive of all the fertilizer elements is 
nitrogen. The supply of this element is also limited. 
Formerly, it was obtained in the form of guano, which is 
manure and decayed bodies of birds, but this supply is 
now practically exhausted. At present the chief source 
is the beds of sodium nitrate, or Chile saltpeter, found 
in Chile. It lies near the surface of the ground in great 
beds, but is so mixed with rock and earth that the leach- 
ing out of the salt is necessary before it is ready for market. 
Nitrogen in the form of sodium nitrate is directly avail- 
able to plants. 
Ammonium sulfate is another important source of 
