4 FORAGE CROPS 
very generally grown, is rich in nutrients, pala- 
table, and capable of use as a green forage or 
as hay; it possesses an important advantage in 
being capable of deriving a part at least of the 
nitrogenous food necessary for its growth from the 
air, and for this reason is regarded as an improving 
rather than an exhausting crop. It supplements 
the corn crop in composition, as well as in its 
power of obtaining nitrogen. Thus, in the growing 
of corn and clover in rotation, better rations are 
obtained and the soil less quickly depleted, than if 
corn alone is grown. 
On the other hand, such crops as rye and wheat, 
while readily grown, are serviceable only for a 
short period as green forage or for soiling, and 
are not so generally useful in their dried state as 
corn or clover. Their usefulness is due chiefly 
to their time of growth and season of maturity, 
which permits of their use as green forage or pas- 
ture when such crops as corn and clover are not 
yet ready. 
The cowpea possesses the characteristics attrib- 
uted to the clover in food acquirements, but it is 
possible to grow it only in the hot season, and it 
therefore serves only as a late summer or fall food. 
Another point of very great importance, and 
one which should be observed in comparing the 
various forage crops, is the food-content in the 
green state. Succulence is of course very impor- 
