2 BULLETIN 291, U. S. DEPARTMENT OF AGRICULTURE. 
lished settlers in this region are those who have depended on live 
stock as their main source of income. In favorable seasons grain 
crops are profitable, but the profit from growing them can doubtless be 
increased if a portion of the grainis consumed on the farm as feed for 
animals. In the driest seasons, however, when small grains are likely 
to be a total failure, forage .crops sufficient to carry animals through 
the winter can nearly always be depended on. This is because the 
most drought-resistant forage crops can be raised on a much smaller 
supply of moisture than the grain crops. 
The native range is used to a large extent for summer pasturage, 
but it is necessary to produce under cultivation most of the forage for 
winter feeding, and it is often necessary to supplement the summer 
pasturage with cultivated crops. It is evident, therefore, that forage 
crops should occupy a very important place in the agriculture of the 
Great Plains. 
In some sections of the northern Great Plains alfalfa, brome-grass, 
and other perennial crops give excellent results, but certain annual 
forage crops appear to be much more dependable in the central 
Plains. Two of the most suitable crops for this region are the millets 
and sorghums. Millets grow and mature in a comparatively short 
season and are often able to escape drought when other crops are 
overtaken. Sorghums endure drought well, standing a long period 
of drought and yet renewing growth upon the return of favorable 
conditions. Both crops have a very low water requirement. 
ADAPTATIONS TO DROUGHT IN MILLET AND SORGO. 
ROOT DEVELOPMENT. 
Millet has a comparatively shallow root system with a great devel- 
opment of fine fibrous roots. It is therefore well adapted to make 
the best use of light rains which wet the soil to a depth of only a few 
inches. The early root growth is somewhat slow, so that the young 
plants are sometimes injured by high winds before the roots are well 
enough established to hold the plants firmly. Sorgo has a much 
deeper root system than millet and can apparently make use of mois- 
ture which is stored 3 or 4 feet deep in the soil. Both crops draw 
heavily upon the supply of soil moisture and are likely to use for 
their growth all of the water that is available in the area penetrated 
by their roots. 
EARLY MATURITY. 
The period of growth of the crop is of great importance under dry- 
land conditions. The ideal crop is one that will mature in a short 
season and therefore lessen the risk of being overtaken by drought. 
The short-season crop has the further advantage of allowing the soil to 
lie fallow for a considerable period of the year when moisture conserva- 
