126 AGRICULTURE. 



or vetch, to prevent the leaching out of valuable 

 fertilizing- materials by the rains. 



The seeds make a valuable concentrated food, 

 but since, as yet, there is no means of thresh- 

 ing them satisfactorily unless gathered by hand, 

 it is quite expensive. 



V. The Soy-bean (Glycine hispida) 

 (Fig. 34) is largely grown in the South, but can 

 be grown wherever Indian corn can be grown 

 successfully. It feeds heavily upon potash, and 

 requires fertilizing with lime, potash, and phos- 

 phorus if the soil is poor in these materials. It 

 should not be planted until the ground is warm. 

 It grows rapidly, and generally requires little 

 cultivation. 



The hay is rich in protein. It should be cut 

 at the time of, or soon after, blooming. The 

 seed yields from twenty-five to forty bushels per 

 acre. The beans are rich in protein and oil, 

 hence they make a desirable concentrated food 

 to be fed in connection with roughage. 



EXERCISE 5. (a) Collect specimens of various legu- 

 minous plants, taking great care to procure the root 

 systems intact. 



(/>) Look for tubercles or nodules on the roots. Where 

 found ? 



(r) Note the relative size of nodules upon different 

 kinds of plants, and upon the same kind of plants 

 grown in different soils. 



(</) Do you find any legumes which have no nodules? 

 If so, test the soil in which they were grown for acid. 



