FORAGE CROPS 159 



producing region of the United States is found in the north 

 central states, reaching from Michigan and Ohio on the east 

 to Kansas and Nebraska on the west. 



Uses of grasses and legumes. Grasses and legumes 

 have two principal uses : ( 1 ) they supply the most impor- 

 tant part of the food of farm animals, and (2) they aid in 

 building up the soil, making it productive for other crops. 

 They are also serviceable in saving the soil from washing 

 and blowing. 



A great proportion of our cattle, horses, sheep and 

 hogs are raised with forage as their chief food. Where 

 good pasturage is available, little or no grain is fed to grow- 

 ing stock, and often none even to milk cows. And when 

 grain is used to fatten stock, or to give strength, as in the 

 case of work horses, forage is required to supply the vol- 

 atile oils as well as bulk and coarseness necessary to diges- 

 tion. 



Both grasses and legumes tend to improve the soil. 

 Their decaying roots, stems and leaves form an important 

 part of the soil, called humus. This vegetable matter not 

 only enriches the soil, but makes it lighter and more por- 

 ous, so that air can better get to the roots of growing 

 plants. It also favors proper drainage in damp soils. 



Legumes and the nitrogen of the soil. Legumes, 

 however, enrich the soil in a special way, and are widely 

 cultivated for this purpose. In order to understand how 

 legumes do their work of improving the soil, it must be 

 known that plants demand certain foods from the soil. One 

 of the most necessary plant foods is nitrogen. If this is 

 lacking in the soil, the crop does not grow well, and the 

 yield is reduced. For example, wheat takes much nitrogen 

 from the soil ; this is the main reason why wheat can not be 

 grown on the same land year after year. The nitrogen be- 

 comes exhausted. The soil is "worn out." It is estimated 

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