Manuring and Rotations 83 
This is the surest means of preserving soil fertility. Prac- 
tically every farm produces a quantity of this by-product 
of animal husbandry, and a wise use of it is fundamental 
to permanent agriculture. Since the very dawn of history 
the excreta of animals have been used as fertilizer. Al- 
though for a long time little was known of the way in 
which it improved the soil, the increased yield of crops 
was evident. Manure is now known to benefit the soil 
by adding directly a quantity of plant-food, by increas- 
ing the organic matter, and by aiding the work of de- 
sirable organisms. It may not in all cases be a com- 
plete and well-balanced fertilizer for beets in all soils, but 
it can always be recommended with safety. Where sugar- 
beets have been raised for any length of time, farmers 
have learned the great value of manure. Probably no 
other common field crop has done more to promote a 
careful use of farm manure. 
The amount to apply depends on that available, the 
nature of the soil, and the rotation used. When beets 
are raised in a regular rotation, the manure can usually 
be applied with greater profit to the sugar-beet crop than 
to almost any other crop in the rotation. An applica- 
tion of five to twenty tons to the acre usually gives good 
results; ten tons is a fair application. The amount de- 
pends in part on the kind of manure. Quality is influ- 
enced by the kind of animal producing it and by a number 
of other factors. Manure produced by poultry and sheep 
is concentrated and dry; that produced by cattle and 
horses contains more moisture and coarse material. The 
manure of any kind of animal is influenced by the kind 
of food it eats and by its age and work. Old animals 
